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1. When the magnetic flux in the coil decreases, the direction of the magnetic flux of the induced current (B). (A) Opposite to the original magnetic flux direction ； (B) Same direction as the original magnetic flux ； (C) It has nothing to do with the original magnetic flux direction ； (D) It is related to the size of the coil. 2. A certain coil has 100 turns, and the current flowing through it is 2A, then the magnetic potential of the coil is (C) ampere-turns. (A)50 ； (B)400 ； (C)200 ； (D)0.02. 3. If a wire is evenly stretched to twice its original length, its resistance will be (D) times its original resistance. (A)2 ； (B)1;(C)0.5 ； (D)4。 4. Law (D) in the circuit states that: The current flowing into any node must be equal to the current flowing out of that node (A) Ohms ； (B) Kirchhoff first ； (C) Lenci ； (D) Kirchhoff second. 5. The power factor is expressed by cosφ, and its formula is (D). (A)cosφ=P／Q ； (B)cosφ=Q／P ； (C)cosφ=Q／S ； 6. The directions of magnetic field lines, current and force are (B). (A) Magnetic lines of force are parallel to the current and perpendicular to the force ； (B) The three are perpendicular to each other ； (C) The three are parallel to each other ； (D) The magnetic lines of force are perpendicular to the current and parallel to the force. 7. In an AC circuit, the current lags behind the voltage by 90°. This circuit belongs to (C) circuit. (A)Composite ； (B) Pure resistance ； (C) Pure inductance ； (D) Pure capacitance. 8. The purpose of installing an arc suppression coil at the neutral point of the transformer is (D). (A) Increase the grid voltage level ； (B) Limit transformer fault current ； (C) Improve the insulation level of transformer ； (D) Compensate the current during grounding and fault. 9. In a DC circuit, the capacitive reactance of a capacitor is (A). (A)Maximum ； (B)Minimum ； (C)zero ； (D) Unable to determine. 10. Thevenin's theorem can equate any active two-terminal network to a voltage source with internal resistance. The internal resistance and electromotive force of the equivalent power supply are (A). (A) Determined by the parameters and structure of the network ； (B) Determined by the size and nature of the connected load ； (C) Determined by network structure and load ； (D) Determined by network parameters and load. 11. The function of a lightning rod is (B). (A)Repelling lightning ； (B) Attract lightning ； (C)Avoid lightning ； (D) Weaken thunder and lightning. 12. The transfer switch of the multimeter is the switch that realizes (A). (A) Various measurements and ranges ； (B)Current on ； (C) Connect the object under test to achieve measurement ； (D) Voltage is connected 13. After using up the multimeter, the selector switch should be set to (C). (A)Resistance ； (B)Voltage ； (C)AC voltage ； (D)Current. 14. One end of the secondary winding of the transformer must be grounded for the purpose of (D). (A) Improve measurement accuracy ； (B) Determine the measurement range ； (C) Prevent secondary overload ； (D) Ensure personal safety. 15. The voltage ratio of each winding of the transformer and their coil turns ratio (B). (A) proportional to ； (B)Equal ； (C)Inversely proportional to ； (D) Irrelevant. 16. In order to prevent the oil from aging too quickly, the temperature of the oil in the upper layer of the transformer must not often exceed (C). (A)60℃ ； (B)75℃ ； (C)85℃ ； (D)100℃. 17. When measuring the insulation resistance of low-voltage cables and secondary cables, (A) megger should be used. (A)500V ； (B)2500V ； (C)1500V ； (D)2000V。 18. The purpose of measuring the DC resistance of the winding is (C). (A) Ensure that the temperature rise of the equipment does not exceed the upper limit ； (B) Measure whether the insulation is damp ； (C) Determine whether the connector is in good contact ； (D) Determine whether the insulation has declined. 19. The main function of insulating oil in oil-less circuit breakers is (C). (A)Cooling ； (B)Lubrication ； (C) Arc extinguishing ； (D) Anticorrosion. 20. The reason why the circuit breaker has arc extinguishing ability is mainly because it has (A). (A) Arc extinguishing chamber ； (B)Insulating oil ； (C)Quick mechanism ； (D) Parallel capacitor. 21. The purpose of conducting gas analysis tests on insulating oil is to check whether (A) phenomenon occurs. (A) Overheating discharge ； (B) Increase in acid value ； (C) Insulation gets damp ； (D) Mechanical damage. 22. Power factor cosφ is a coefficient that expresses the capacity of electrical equipment, and its size is (B). (A)P／Q ； (B)P/S ； (C)P／X ； (D)X/Z. 23. The accuracy requirements of electrical test instruments are at level (A). (A)0.5 ； (B)1.0 ； (C)0.2 ； (D)1.5. 24. After the 35kV voltage transformer is overhauled, the medium at 20°C should not be greater than (C). (A)2% ； (B)2.5% ； (C)3% ； (D)3.5%. 25. In a 35kV multi-oil circuit breaker, the main function of oil is (D). (A) Extinguish the arc ； (B) Phase insulation ； (C) Insulated from ground ； (D) Arc extinguishing, phase-to-phase insulation and ground insulation 26. The function of a lightning arrester is that it can prevent (B) damage to equipment. (A) Direct lightning strike ； (B) Progressive wave ； (C)Induction mine ； (D) Third harmonic. 27. The contacts of vacuum circuit breakers often use (C) contacts. (A) Bridge type ； (B)Finger shape ； (C)Butt type ； (D) Insert. 28. The function of the transformer is (D). (A) Produce electrical energy ； (B)Consumption of electrical energy ； (C)Produces and consumes electricity ； (D)Transfer power. 29. Pure sF6 gas is (AJ’s. (A)Non-toxic ； (B)Toxic ； (C)Neutral ； (D) beneficial. 30. For the GW5 series isolating switch, the three-phase contact at different stages should not exceed (B) mm. (A)3 ； (B)5 ； (C)7 ； (D)10。 31. Pure capacitive components in the circuit (A) electric energy. (A)Storage ； (B)Distribution ； (C)Consumption ； (D) change. 32. When the temperature rises, the DC resistance of the transformer (A). (A)As it increases ； (B)With the decrease ； (C) unchanged ； (D) No 33. The rated breaking current of the high-voltage circuit breaker refers to breaking under specified conditions (C). (A) Maximum short-circuit current maximum value ； (B)Maximum impact short-circuit current ； (C) Maximum short-circuit current effective value ； (D) 2 times the maximum load current. 34. The way to hold the chisel is (C). (A)1 type ； (B)2 types ； (C) 3 types ； (D) 4 species. 35. Cutting off the no-load transformer from the power grid will cause (B). (A) Grid voltage decreases ； (B)Overvoltage ； (C) Overcurrent ； (D) Reactive power decreases. 36. After the transformer is put into operation, it needs to be overhauled every (C) years. (A)1-2 ； (B)3-4 ； (C)5～10 ； (D)11～12. 37. When the voltage level is 220kV, the safe distance between the human body and the electrified object should not be less than (B). (A)1.0 ； (B)1.8(C)2.5 ； (D)3.6. 38. If the person who receives an electric shock has his heart stopped but is still breathing, (C) first aid should be given immediately. (A) Supine chest press method ； (B) Supine back pressure method ； (C)External chest cardiac compressions ； (D) Mouth-to-mouth breathing. 39. When there is a power outage on the line, the sign (C) should be hung on the line switch and the knife gate operating handle. (A) Work here ； (B) Stop the danger of high voltage ； (C) No one is allowed to work on the closing line ； (D) Running. 40. The capacity of the transformer should be selected according to its installation location (D). (A) Transformer capacity ； (B) Line capacity ； (C)Load power supply ； (D) Maximum short circuit current. 41. When electrical workers work near a 10kV power distribution device, the minimum safe distance between their normal range of movement and live equipment is (D). (A)0．2m ； (B)0．35m ； (C)0．4m ； (D)0.5m. 42. The most dangerous way for electric current to pass through the human body is (B). (A) Left hand to right hand ； (B)Left hand to foot ； (C) Right hand to foot ； (D)Left foot to right foot. 43. After the workpiece is filed, method (C) can be used to check its flatness. (A)Dimensions ； (B)Observe ； (C) Translucent ； (D) Control. 44. The coupling capacitor is used for (A). (A) High frequency channel ； (B) Pressure equalization ； (C) Improve power factor ； (D) Compensate for reactive power. 45. When an object is acted upon by a balancing force, it is at rest or does (C). (A) Variable speed linear motion ； (B) Variable speed curve movement ； (C) Uniform linear motion ； (D) Uniform curved motion 46. The function of the wave arrester is to prevent (B) current from flowing through. (A)Power frequency ； (B)High frequency ； (C)Thunder and lightning ； (D) Failure. 47. The maximum operating temperature of Class A insulation material is (A). (A)90℃ ； (B)105℃ ； (C)120℃ ； (D)130℃. 48. Any construction worker who discovers others working in violation of regulations should (B). (A) The supervisor who reports the violation will stop him ； (B) Stop it immediately ； (C) Report to full-time security personnel to stop it ； (D) Report to the public security organs to stop it. 49. The oil pipeline connecting the CY3 hydraulic mechanism and the working cylinder has an upward slope of approximately (B) along the direction of the operating mechanism to facilitate exhaust. (A)1% ； (B)0.5% ； (C)2% ； (D)1.5%. 50. The stroke of the working cylinder of SW2-110 oil circuit breaker is (B)mm. (A) 134±1 ； (B) 132±1 ； (C) 136±1 ； (D) 135±1. 51. We call the difference in potential between two points (C) (A) electromotive force ； (B)Potential difference ； (C)Voltage ； (D) Voltage difference. 52. The size of the electromotive force of the power source indicates (B) the power of doing work. (A) Electric field force ； (B)External force ； (C) Friction ； (D) Magnetic force. 53. The three elements of force refer to the magnitude, direction and (D) of the force. (A)Strength ； (B)Unit ； (C)Synthesis ； (D) Point of action. 54. If a voltage of 60V is applied to both ends of a 30Ω resistor, the current through the resistor is (D). (A)1800A ； (B)90A ； (C)30A ； (D)2A。 55. In a DC circuit with constant voltage, when the resistance value increases, the current (C) increases. (A) unchanged ； (B)increase ； (C) decrease ； (D)Variable. 56. The AC 10kV bus voltage refers to the AC three-phase three-wire system. (A)Line voltage ； (B)Phase voltage ； (C) Line voltage ； (D) Equipment voltage. 57. The three elements of sinusoidal alternating current are maximum value, frequency and (D). (A) Valid value ； (B)Minimum value ； (C)Period ； (D) Initial phase angle. 58. The lighting voltage we use is 220V, which is the effective value of (A) (A) alternating current. ； (B)Maximum value ； (C)Constant value ； (D) Instantaneous value. 59. When the power supply is connected in Y shape, the numerical relationship between line voltage UL and phase voltage Uph is (A). (A) UL=√3Uph ； (B)UL=2Uph ； (C) UL=Uph ； (D)UL=3Uph 60. A resistor marked "1kΩ, 10kW", allowable voltage (B). (A) No limit ； (B)There is a maximum limit ； (C)There is a minimum limit ； (D) cannot be expressed. 61. In an AC circuit, the (C) value of the current of a certain component is a quantity that changes with time. (A)valid ； (B)Average ； (C)Instantaneous ； (D)Max. 62. When there is a current (A) in the coil, a self-induced electromotive force is generated at both ends of the coil. (A)When changing ； (B) When unchanged ； (C) When it is very large ； (D) very small. 63. The relationship between the maximum value Im and the effective value I of alternating current is (A). (A)Im=√2I ； (B)Im=√2I／2 ； (C)Im=I ； (D)Im=√3I. 64. In a sinusoidal AC circuit, the equation of node current is (A). (A)∑I=0 ； (B)∑I=1 ； (C)∑I=2 ； (D)∑I=3. 65. The resistance of a section of wire is R. If you fold it in half and create a new wire, its resistance is (D). (A)2R ； (B)R ； (C)R／Q ； (D)R/4. 66. The function of the base of the triode is (D) carrier. (A) launch ； (B)Collect ； (C)Output ； (D)Control. 67. The process of converting alternating current into direct current is called (C). (A) Transformer ； (B) Voltage stabilization ； (C) Rectification ； (D) Filtering. 68. During the repeated magnetization process of ferromagnetic materials, the change in magnetic induction intensity always lags behind the change in magnetic field intensity. This phenomenon is called (B). (A) Magnetization ； (B) Hysteresis ； (C)Remanent magnetism ； (D)Demagnetization. 69. During the charging process of the capacitor, (B). (A) The charging current cannot change ； (B) The voltage at both ends cannot be sudden. ； (C)Stored energy mutates ； (D) The stored electric field undergoes a sudden change. 70. If the initial phase angle A ф1-ф2 > 0° of two sinusoidal alternating currents with the same frequency, this situation is (B). (A) Two sinusoidal alternating currents in phase ； (B) The first sinusoidal alternating current leads by two ； (C) Two sinusoidal alternating currents are in opposite phases ； (D) The second sinusoidal alternating current is advanced by two. 71. The arc extinguishing ability of SF6 gas is (D) times greater than that of air. (A)30 ； (B)50 ； (C)80 ； (D)100。 72. The heater of the hydraulic mechanism of the SW6 oil-less circuit breaker should be turned on at (B). (A) a 5℃: (B)0℃ ； (C)2℃ ； (D)4℃. 73. In power transformers, the function of oil is (B). (A)Insulation and arc extinguishing ； (B)Insulation and heat dissipation ； (C)Insulation and rust prevention ； (D) Heat dissipation and rust prevention. 74. For a voltage transformer in operation, in order to avoid generating a large short-circuit current and burning out the transformer, a transformer (D) is required. (A) Must be grounded at one point ； (B) Overloading is strictly prohibited ； (C) Two points of grounding are required ； (D) Secondary short circuit is strictly prohibited. 75. After the aluminum alloy equipment joint is overheated, its color will appear (C). (A)ash ； (B)Black ； (C)Gray ； (D)Silver white. 76. In order to reduce the voltage recovery speed between the contacts and prevent oscillation overvoltage, (B) is sometimes installed between the contacts of the circuit breaker. (A)Voltage equalizing capacitor ； (B) Parallel resistance ； (C) Pressure equalizing belt ； (D) Parallel voltage equalizing ring. 77. If the top iron cap, interface, screws, etc. of the outdoor oil circuit breaker are not tightly sealed, water will enter (A). (A) Oil level rises ； (B) Large buffer space ； (C) Oil temperature rises ； (D) The oil level drops. 78. When starting and stopping the pump during operation of the hydraulic mechanism, the reason why the piston rod position is normal and the mechanism pressure increases is (B). (A) High pre-charge pressure ； (B) Hydraulic oil enters the cylinder ； (c) Nitrogen leakage ； (D) Institutional failure. 79. During the voltage regulating process of the on-load voltage regulating device, the relationship between the switching contact and the selecting contact is (B). (A) The former moves before the latter ； (B) The former moves later than the latter; (C) moves at the same time; (D) both do not move. 80. When the oil-immersed transformer is dry, its winding temperature does not exceed (C). (A)110℃ ； (B)100℃ ； (C)95℃ ； (D)85℃. 81. A magnetic field will be generated around any current-carrying conductor, and the strength of the magnetic field is related to (A). (A) The size of the current passing through the conductor is related to ； (B) It is related to the thickness of the conductor; (C) It is related to the material properties of the conductor; (D) It is related to the spatial position of the conductor. 82. The voltage equalizing ring of the arrester mainly achieves voltage equalizing by its capacitance to (B). (A) land ； (B)Flange of each section ； (C)Wire ； (D) around. 83. If the equipment is damaged due to an accident, restorative maintenance that must be carried out immediately is called (B) maintenance. (A) Temporary ； (B)Accidental ； (C)Plan ； (D) Abnormality. 86. The rated capacity on the transformer nameplate refers to (c) power. (A) meritorious service ； (B)Reactive work ； (C) apparent ； (D)Max. 87. The three main technical indicators for measuring power quality are voltage, frequency and (A). (A)Waveform ； (B)Current ； (C)Power ； (D)Load. 88. The main function of the isolating switch is (C). (A) Breaking current ； (B) Pull line ； (C) Cut off power supply ； (D) Pull the empty busbar together. 89. When tightening a nut with a wrench, if the same amount of force acts on the wrench, the force will be greater when it is farther from the center of the nut than when it is closer (C). (A) Effortless ； (B)Equal ； (C)Effort saving ； (D) Effortless. 90. The grounding of the electrical equipment shell belongs to (C). (A) Working ground ； (B) Lightning protection grounding ； (C) Protective grounding ； (D) Large ground. 91. The overcurrent protection of the line is protection (C). (A) Switch (B) Converter ； (C) Line ； (D)Busbar. 92. When (D) fault occurs, the zero-sequence current filter and zero-sequence voltage transformer have zero-sequence current output. (A) Three-phase disconnection ； (B) Three-phase short circuit ； (C) Three-phase short circuit and grounding ； (D) Single-phase grounding. 93. Atmospheric overvoltage is caused by (D). (A)Windy ； (B)Rain ； (C)Dense fog ； (D)Thunder and lightning. 94. The starting current for line overcurrent protection setting is (C). (A)The load current of the line ； (B)Maximum load current ； (C) Greater than the allowable overload current ； (D)The current of the line. 95. When a three-phase symmetrical short circuit occurs in the power grid, the short circuit current contains (C) component. (A)DC ； (B) Zero sequence ； (C) Positive sequence ； (D) Negative sequence. 96. When a short circuit occurs in the power system, the total impedance of the power grid will be (A). (A) decrease ； (B)increase ； (C) unchanged ； (D) Suddenly big and sometimes small. 97. The grounding resistance of the substation grounding network has nothing to do with (C). (A)Soil resistivity ； (B)Grounding grid area ； (C)Number of equipment in the site ； (D) Ground body size. 98. The regulations on electric power production safety stipulate that in order to improve the level of safety production, (B) modernization, safety equipment modernization and safety management modernization must be achieved. (A)Technology ； (B)Equipment ； (C)Facility ； (D) Protection. 99. The impedance voltage of the transformer can be obtained from the (D) data of the transformer. (A) No-load test ； (B) Voltage ratio test ； (C) Withstand voltage test ； (D) Short circuit test. 100. There is a voltage transformer with a primary rated voltage of 5000V and a secondary rated voltage of 200V. When using it to measure the voltage, the secondary voltmeter reads 75V and the measured voltage is (C)V. (A)15000 ； (B)25000 ； (C)1875 ； (D)20000。 101. When wires pass through alternating current, an alternating electric field is generated between the wires and between the wires and the ground, so there is (C). (A)Reactance ； (B) Resistance ； (C) Capacitive reactance ； (D)Impedance. 102. If the insulation grade of electrical equipment is Class B, then its limit operating temperature is (O)℃. (A)100 ； (B)110 ； (C)120 ； (D)130。 103. For transformers with strong oil guide cooling, the oil flow from the oil pump enters (C) for cooling. (A) Fuel tank ； (B)Iron core ； (C)Coil ； (D) Oil pillow. 104. When pulling long objects, they should be pulled along the length direction, and the lashing point should be at the center of gravity (A). (A)Front end ； (B)Backend ； (C) Center of gravity ； (D) Midrange. 105. When tapping holes with a diameter of 12mm in steel and brass plates, (B) drill bit should be selected. (A)10.0mm ； (B)10．2mm ； (C)10．5mm ； (D) 10.9mm. 106. The (D) protection of the substation must be considered before disassembling and disassembling large-scale 220kV substation transformers. (A)High frequency ； (B)Impedance ； (C) Overcurrent ； (D) Mother difference. 107. The stability of the power system refers to (C). (A)The length of the system’s trouble-free time ； (B) The ability of two power grids to operate in parallel ； (C) System anti-interference ability ； (D) Utilization rate of electrical equipment in the system. 108. The main protection when an internal fault occurs in the transformer is (A). (A)Gas ； (B) Differential ； (C) Overcurrent ； (D) Quick break. 109. All electrical equipment classified as Class I or Class II equipment is called (C). (A) Good equipment ； (B)Excellent equipment ； (C) intact equipment ； (D) All brand-name equipment. 110. When measuring the insulation resistance of a transformer coil with a rated voltage above lkV, a (D)V megger must be used. (A)500 ； (B)1000 ； (C)1500 ； (D)2500。 111. The phase relationship between the corresponding voltages of the primary and secondary windings of the power transformer is called (A). (A)Connection group ； (B)Short circuit voltage ； (C) No-load current ； (D) Short circuit current. 112. If the wiring group of a three-phase power transformer is Y, dll, then the secondary line voltage leads the primary line voltage (A). (A)30° ； (B)60° ； (C)120° ； (D)45°. 113. The purpose of connecting a resistor in series with the tripping and closing position monitoring light of the circuit breaker is (C). (A) Limit the current through the trip and closing coil ； (B) Compensation lamp rated voltage ； (C) Prevent the circuit breaker from tripping accidentally due to a short circuit in the lamp holder ； (D) To extend the life of the bulb. 114. When the secondary side of the transformer is open-circuited at rated voltage, the power consumed in its core is called (A). (A)Iron loss ； (B)Copper loss ； (C)Reactive power loss ； (D) Line loss. 115. The temperature indicated by the pressure thermometer of the transformer is (A). (A) Upper oil temperature ； (B)Iron core temperature ； (C) Winding temperature ； (D) Shell temperature. 116. The ratio of the number of equipment rated as intact equipment to the number of equipment participating in the assessment is called (D). (A) Good rate of equipment ； (B)Pass rate of equipment ； (C)Equipment rating ratio ； (D) Equipment integrity rate. 117. When filing, the thickness of the file teeth depends on (C) (A) the shape of the workpiece to be processed ； (B) Dimensions of processing surface ； (C) Workpiece material and properties ； (D)The material of the file itself. 118. There are five grades of file thickness: No. 1, 2, 3, 4, and 5. No. 3 is used by hand (C). (A) Rasp ； (B) Medium coarse rasp ； (C)Fine file ； (D) Double fine file. 119. The order of dismantling the lifting scaffolding is (A). (A) First remove the upper scaffolding ； (B) Remove the large crossbar first ； (C) Remove the inner shelf first ； (D) Randomly. 120. When working on a particularly humid, well-conducting ground or in a metal container, the voltage of the portable light shall not exceed (A)V. (A)12 ； (B)24 ； (C)36 ； (D)6。 121. When using a pulley to place soft or tight wires, the diameter of the pulley should be no less than (B) times the diameter of the conductor. (A)15 ； (B)16 ； (C)17 ； (D)20。 122. There are (B) types of commonly used knots. (A)10 ； (B)14 ； (C)8 ； (D)12。 123. Lifting a light and slender object vertically should be marked (A). (A) Back button ； (B) Live buckle ； (C)Back button ； (D) Direct deduction. 124. The crowbar is one of the tools frequently used in lifting operations. When operating, the gravity arm (C) is the force arm. (A) Greater than ； (B) is equal to ； (C)Less than ； (D) Slightly larger. 125. When using the rolling method to transport equipment, there are certain requirements for the number of rollers placed. If there are fewer rollers, the required traction (A) will be required. (A)increase ； (B) decrease ； (C) unchanged ； (D) Slightly smaller. 126. When using a high-pressure washing machine, the working pressure must not exceed (B) the allowable pressure of the high-pressure pump. It is strictly forbidden to aim the spray gun at people, and the metal shell of the washing machine must be grounded. (A) is equal to ； (B)Exceed ； (C)Less than ； (D) Long-term excess. 127. The shaking speed of the megohmmeter during normal measurement is (A)r/min. (A)120 ； (B)90 ； (C)200 ； (D)10。 128. When filing, the pressure applied by both hands on the file should be (A). (A) Ensure that the file is stable and does not swing up and down ； (B) The pressure on the left hand is smaller than the pressure on the right hand, and the pressure on the left hand increases from small to large as the file advances. ； (C) The pressure on the left and right hands is equal, and when the file is advanced, the file swings up and down slightly. ； (D) At will. 129. Oil-immersed transformers should be transported upright, and the inclination angle should not exceed (A) 15° ； (B) 20° ； (C) 25° ； (D)30°. 130. The flange height of the crane drum should be one diameter higher than the surface of the outermost rope. When the hook is placed at the lowest position, there should be at least (C) loops of rope on the drum. (A)1 ； (B)2～3 ； (C)5 ； (D)4。 131. Use two ropes to lift a heavy object. When the angle between the rope and the vertical line of the hook is (A), the force on the rope is the mass of the lifted object. (A)0° ； (B)30° ； (C)45° ； (D)60°. 132. When using clips to fix the wire rope, the bent end of the wire rope should be clamped firmly. When the diameter of the wire rope is 19.5mm, (B) clips should be used. (A)2 ； (B)3 ； (C)4 ； (D)5。 133. When the lifting wire rope is connected by plugging method, the plugging length should be 15-22 times the diameter, but generally it should not be less than (A)mm. (A)500 ； (B)400 ； (C)300 ； (D)100。 134. When the lifting wire rope is connected with clips, different numbers of clips should be used according to the diameter of the wire rope, but at least no less than (C) should be used. (A)5 ； (B)4 ； (C)3 ； (D)2。 135. There is a part that needs to be filed. The machining allowance is 0.3mm and the required dimensional accuracy is 0.15mm. The (B) file should be selected for processing. (A) thick ； (B)Medium coarse ； (C) fine ； (D) Double thin. 136. During sawing, due to different sawing materials, the saw blades used are also different. Now when cutting aluminum and copper materials, (A) should be selected. (A) Rough saw blade ； (B) Medium coarse saw blade ； (C)Fine saw blade ； (D) Any saw. 137. The single-foot gauge is a (B) tool. (A) Like a compass, it is used to process parts and draw circles. ； (B) Find the center of the cylindrical part ； (C) Measure the inner diameter of the pipe ； (D) When measuring the outer diameter of the pipe 138, when chiseling on the horizontal plane or side, deburring the workpiece, or using a short and small chisel, the method (B) should be used to hold the chisel. (A) Overhand grip ； (B) Reverse grip ； (C) Stand and hold ； (D) Forward and reverse grip. 139. The piston stroke of a hydraulic jack is generally (B)mm. (A)150 ； (B)200 ； (C)250 ； (D)100。 140. When the wire rope is inserted into the sleeve, the broken end length is 45 to 48 times the diameter of the steel wire rope, the length of the sleeve is 13 to 24 times the diameter of the steel wire rope, and the insertion length is (C) times the diameter of the steel wire rope. (A)25 ； (B)26 ； (C)20～24 ； (D)15-20。 141. When two or more steel wire ropes are used to lift heavy objects, when the angle of the steel wire ropes increases, the load on the steel wire ropes will be (A). (A)increase ； (B) decrease ； (C) unchanged ； (D) suddenly becomes smaller. 142. When lifting, the greater the angle between the two steel wire ropes (but generally not greater than 60°), the greater the mass that can be lifted (B). (A)big ； (B)small ； (C) unchanged ； (D)Slightly changed. 143. Use of gasoline blowtorch and kerosene blowtorch (B). (A)Can be replaced ； (B)Cannot be replaced ； (C) Same ； (D) Alternate. 144. When using a multimeter, you should pay attention to the (C) transfer switch. If you make a mistake, the meter may be burned out. (A)Function ； (B) Range ； (C) Function and range ； (D) Location. 145. The absorption ratio measured with a megger is the ratio of insulation resistance when measuring (A). When the temperature is 10-30°C, the absorption ratio is 1.3-2.0 and is qualified. (A)15s and 60s ； (B)15s and 45s ； (C)20s and 70s ； (D)20s and 60s. 146. The positioning nails used for transporting the transformer should be (C). (A) Reinforced insulation ； (B) Not moving at the original position ； (C)Remove or reverse installation ； (D) Not considered. 147. When hemp rope is used with a pulley, the minimum diameter of the pulley is ≥ (A) times the diameter of the hemp rope. (A)7 ； (B)5 ； (C)3 ； (D)4。 148. During maintenance work, if slipping is found when lifting with a reverse chain, do (B). (A) Pay attention to safety when using ； (B) Need to be repaired before use ； (C) Use strictly prohibited ； (D) Not considered. 149. When using the hook, it must be used strictly in accordance with the regulations. In use (B). (A) Can only be used at 70% of the specified load ； (B) Do not overload ； (C) Can only exceed 10% of the specified load ； (D) It can be used at 1.5 times the specified load for a short period of time. 150. The safety factor of the lifting wire rope is (B). (A)4.5 ； (B)5～6 ； (C)8-10 ； (D)17。 151. Although there are no broken wires in the lifting wire rope, when each wire is worn or corroded beyond (B) of its diameter, it should be scrapped and is no longer allowed to be used for load reduction. (A)50% ； (B)40% ； (C)30% ； (D)20%. 152. When clamping the processed surface, in order to avoid damaging the surface, the vise mouth should be lined with (B). (A) wooden board ； (B) Copper jaws ； (C)Cotton cloth or cotton silk ； (D) Rubber 153. During the hoisting operation, the guide pulley is used for lifting. There are four situations in which the angle between the ropes at both ends of the guide pulley is. Only when the included angle is (A), the force on the rope is the smallest. (A)120° ； (B)90° ； (C)60° ； (D)0°. 154. When the grinding machine is working, the more turns (A) the running rope has around the grinding core, the less effort it will take for the person tightening the tail rope. (A) Many ； (B) less ； (C) tight ； (D)Loose. 155. When using winch traction equipment to lift heavy objects, when the running rope is in the middle of the drum, the position of the running rope and the drum should generally be (C). (A) A small angle ； (B) The deflection angle is less than 15° ； (C)Vertical ； (D) Any angle. 156. The power required by the winch is roughly proportional to the product of the load and (B). (A)Effect ； (B)Speed ； (C)Power factor ； (D)Angle. 157. The thickness of the saw blade teeth can be selected according to the (A) degree of the cutting material. (A) Thickness, soft and hard ； (B)Soft, hard ； (C)Thickness ； (D)Thickness and softness. 158. Hemp rope is used for general lifting operations, and its safety factor is 5. It is used for hanging ropes, and its safety factor is (A). (A)14 ； (B)10 ； (C)8 ； (D)7。 159. The safety factor of steel wire rope when used in motorized lifting equipment is 5-6, and the safety factor when used in manual lifting equipment is (C). (A)6 ； (B)5.5 ； (C)4.5 ； (D)4。 160. When the steel wire rope is used for machine-powered lifting equipment, the safety factor should be (C). (A)2 ； (B)2.5～4 ； (C)5～6 ； (D)10。 161. When the steel wire rope is used as a lashing rope for tying lifting objects, the safety factor should be (C). (A)5-6 ； (B)8 ； (C)10 ； (D)4-6。 162. For workpieces that need to be scraped, the scraping allowance left is generally between (A). (A)0.05～0.4mm ； (B)0.1～0.5mm ； (C)1～5mm ； (D)0.5～1mm. 163. When carving is approaching the end of the workpiece, the remaining part must be (B) chiseled. This is especially true for brittle materials such as bronze and cast iron, otherwise they will crack at the ends. (A)Persistence ； (B)Turn around ； (C) lay flat ； (D) Stand upright. 164. When preparing potassium hydroxide or sodium hydroxide electrolyte, in order to avoid the solution splashing on the body, burning the skin or damaging the clothes, (B) should be prepared. (A)5% soda water ； (B) 3% boric acid aqueous solution for washing ； (C)Tap water ； (D)Alkaline water. 165. When measuring the insulation of a circuit with a rectifier element, do not pressurize the rectifier element. Both ends of the rectifier element (A) should be connected. (A)Short circuit ； (B)Open circuit ； (C)Remove ； (D) Not considered. 166. When an SF6 circuit breaker needs to be disassembled and overhauled, (B) should be done after recovering the SF6 gas. (A) Decomposition work can be carried out ； (B) Use high-purity N: The interior can be decomposed after gas flushing twice and vacuuming. ； (C) Decompose after vacuuming ； (D) Flush with N2 gas without vacuuming. 167. The minimum phase-to-phase safety distance of 10kV outdoor power distribution device is (B)mm. (A)125 ； (B)200 ； (C)400 ； (D)300。 168. In order to simplify the AC withstand voltage test of the secondary circuit on site, it is stipulated that when the circuit insulation resistance value is above 10Mn, it can be tested with a (B)V megohmmeter. (A)1000 ； (B)2500 ； (C)500 ； (D)5000。 169. The insulation resistance of the low-voltage motor coil that has not been dried at normal temperature should be greater than or equal to (A)Mn, and the absorption ratio at a temperature of 15-30t2 should be greater than or equal to 1.3 before it can be put into operation. (A)0.6 ； (B)1 ； (C)1.5 ； (D)0.5. 170. If the insulation resistance of a motor that has not been dried and is difficult to dry in a stationary state is not less than (C) MΩ, it can be put into operation first and dried during operation. (A)0.6 ； (B)1;(C)0.2 ； (D)0.5. 171. Inflammable and explosive items should be removed within (A)m around the welding and cutting site. When removal is not possible, reliable isolation or protective measures must be taken. (A)5 ； (B)7 ； (C)10 ； (D)4。 172. When removing (B) from SF6 circuit breakers and combination electrical appliances, workers must wear personal protective equipment such as rubber gloves, goggles, and gas masks. (A)Insulation parts ； (B)Adsorbent ； (C) Non-toxic parts ； (D) Conductive 173. Since the lightning intrusion voltage felt on the protected equipment is higher than the residual voltage of the bus arrester, it is necessary to check whether the (B) distance from the arrester to the main transformer and other equipment meets the regulatory requirements. (A) Geometric mean ； (B)Maximum electrical ； (C) Straight line ； (D) Arithmetic mean distance. 174. All air piping systems of pneumatic mechanisms should be checked for air leakage at rated air pressure, and the pressure drop should not exceed (A) within 24 hours. (A)10% ； (B)15% ； (C)5% ； (D)20%. 175. After the SF6 circuit breaker was disassembled and overhauled, the original gas (C). (A)Can continue to be used ； (B) Can continue to be used after purification treatment ； (C) The toxicity test is passed and it can continue to be used after purification treatment. ； (D) Those that pass the toxicity test can continue to be used. 176. When the SF6 circuit breaker is disassembled and overhauled on site, it is stipulated that the relative humidity of the air should be greater than (C). (A)90% ； (B)85% ； (C)80% ； (D)60%. 177. Strictly control the vacuum drying process of the instrument transformer. The three elements of the drying process of the instrument body refer to (A). (A) Vacuum degree, temperature, time ； (B)Humidity, pressure, temperature ； (C) Insulation, medium, temperature ； (D) Vacuum degree, pressure, time. 178. When the SF6 transformer is undergoing handover test, its internal gas humidity should not be greater than (C)pL. (A)250 ； (B)300 ； (C)150 ； (D)68。 179. When the SW6-220 circuit breaker is in the closing position, adjust the nut at the end of the elastic spring so that the effective length of the closing holding spring is (B) mm. (A)400±5 ； (B)455±5 ； (C)480±5 ； (D)440±5. 180. During the opening process of the circuit breaker, the movable contact rebounds back to the opening position. The rebound should be less than (A)mm. No oil or stuck will cause the buffer gap to be too large. (A)8-12 ； (B)20 ； (C)25 ； (D)25～30. 181. During regular inspection of MR type on-load tap-changer, the time for which the diverter switch components are exposed to the air should be shortened as much as possible, and the maximum time should not exceed (B)h. (A)12 ； (B)10 ； (C)18 ； (D)15。 182. The on-load tap changer arc contact should be replaced when one of all contacts reaches the minimum diameter of the contact (A). (A) All arc contacts ； (B) The arc contact with the largest ablation amount ； (C) All arc contacts of this phase ； (D) All ablated arc contacts. 183. When installing an expander on a transformer, weather conditions (B) should be selected. (A) Cloudy, 75% humidity ； (B) Sunny day, humidity 60% ； (C) Cloudy day, humidity 70% ； (D) Rainy days 184. The deviation between the measured reactance of the current-limiting reactor and its guaranteed value shall not exceed (A). (A) ±5% ； (B) ±10% ； (C) ±15% ； (D) ±17%. 185. For GW6 type isolating switch, the deflection of the upper end of the movable contact at the final closing position shall not be greater than (A)mm. (A) ±50 ； (B) ±70 ； (C) ±60 ； (D) ±100. 186. After the transformer is overhauled, the winding insulation resistance absorption ratio shall not be lower than (A) in the range of 10-30C. (A)1.3 ； (B)1.0 ； (C)0.9 ； (D)1.0~1.2. 187. The acid value of transformer oil should not be greater than (c) mgKoH/s, and the water-soluble acid value pH should not be less than 4.2, otherwise it should be dealt with. (A)0.2 ； (B)0.3 ； (C)0.1 ； (D)0.15. 188. Use a 1000V megger to measure the insulation resistance value of the secondary circuit. The standard of the secondary circuit insulation resistance is: The equipment during operation shall not be lower than (B)MΩ. (A) 2 ； (B)1 ； (C)5 ； (D)10。 189. To measure the insulation resistance of transformer windings above 10kV, use an (A)V megger. (A)2500 ； (B)500 ； (C)1000 ； (D)1500。 190. The busbar compensator must not have cracks, wrinkles or broken strands, and its total cross-section after assembly should not be less than (B) times the busbar cross-section. (A) 1 ； (B)1.2 ； (C)1.5 ； (D)2。 191. The cable line is equivalent to a capacitor. After a power outage, there is still residual charge on the line and (A) to the ground. Therefore, it must be fully discharged before it can be touched by hand. (A)Potential difference ； (B) Equipotential ； (C) very small potential ； (D)Current. 192. In the oil circuit breaker, the most basic principle of arc extinguishing is to use the arc to burn in the insulating oil, causing the oil to decompose into high-pressure gas, blowing the arc, so that the arc is cooled by (C) and finally extinguished. (A) thicken ； (B) thinning ； (C) Stretch ； (D) becomes shorter. 193. For electromagnetic operating mechanism, the fuse specification of the main closing fuse should be (A) times the rated current value of the closing coil. (A)1/3-1/4 ； (B)1/2 ； (C)1/5 ； (D)1.5. 194. Rectangular busbars should be bent at right angles, and there should be no cracks or significant wrinkles at the bends. When aluminum busbars of 125mm x 10mm and below are welded into flat bends, the minimum allowable bending radius R is (B) times the busbar thickness. (A)1.5 ； (B)2.5 ； (C)2.0 ； (D)3。 195. The minimum allowable bending radius R of rectangular aluminum busbars of 195 and 125mm × 10mm and below is welded to a straight bend and is (B) times the width of the busbar. (A)1.5 ； (B)2 ； (C)2.5 ； (D)3。 196. When adding new gas to SF6 equipment, the water content in the cylinder should not be too dry (C). (A)100μL/L ； (B)150μL/L ； (C)68μL/L ； (D)250μL/L. 197. If the contact finger of the GW7-220 isolating switch is severely burned, it should be replaced if the burn or wear depth is greater than (B) mm. (A)1 ； (B)0.5 ； (C)2 ； (D)0.3。 198. When the temperature of the insulating oil of outdoor circuit breakers is below -10°C, (B) transformer oil should be used. (A)25# ； (B)45# ； (C)30# ； (D)10#. 199. The starting voltage of the opening electromagnet and closing contactor of the electromagnetic mechanism should be the rated voltage of (A). (A)30%-65% ； (B)35%-65% ； (C)65% to 80% ； (D)65%. 200. During the handover test of the arc suppression coil, compare the actual measured value of the DC resistance of the winding and the bushing with the factory value. The change should not be greater than (B). (A)1% ； (B)20% ； (C)0.5% ； (D)70%. 201. Hard bus down conductors generally use (A) as a model. (A) 8-well galvanized iron wire ； (B) 10# galvanized iron wire, (C) aluminum wire ； 202. After the main blade of the GW7 isolating switch is closed, the gap between the moving contact and the static contact is (B)mm, and the height error between the center of the moving contact and the center of the static contact is less than 2mm. (A)20～30 ； (B)30-50 ； (C)55 ； (D)50～60. 203. During the overhaul of the transformer hanging core, the time the transformer body is exposed to the air is calculated from the time when the transformer body comes into contact with the air (oil filling time is not included). When the relative air humidity is greater than 65% and less than 75%, exposure (C) h is allowed. (A)16 ； (B)20 ； (C)12 ； (D)15。 204. The power frequency withstand voltage test can assess transformer (D) defects. (A) Insulation damage between coil turns ； (B) The insulation distance between the outer coil phases is too small ； (C) The insulation between the high-voltage coil and the high-voltage tap lead is weak ； (D) The insulation between the high-voltage coil and low-voltage coil leads is weak. The oil filling time of transformers of 205, 220kV and above should not be less than (A) (A)6h ； (B)4h ； (C)2h ； (D)3h。 206. When the GW5 type isolating switch is under the pull of the busbar, the contact point of the contact deviates outward and the gap of the contact finger is not greater than (A)mm. (A)10 ； (B)15 ； (C)18 ； (D)20。 207. The center distance and height error between the circuit breaker and the operating mechanism foundation should not be greater than (C) mm. (A)20 ； (B)25 ； (C)10 ； (D)15。 208. When the capacitance value of the parallel capacitor is in (B) and the measured capacitance value does not exceed ±10% of the factory measured value, then the capacitance value is within the qualified range. (A) At the time of handover ； (B) When handing over the preliminary test ； (C)Preliminary test ； (D) During minor repairs and temporary inspections. 209. When the transformer and transformer body are vacuum dried in the steam drying room, the maximum temperature control point is (B). (A)130℃±5℃ ； (B)105℃±5℃ ； (C)95℃±5℃ ； (D)65℃±1℃. 210. When inspecting the arc extinguisher of the SW2-63G circuit breaker, it is found that there is damage and peeling. If it is light, it can be coated with a layer of (A), and if it is serious, it should be replaced. (A)1154# or 185# insulating paint ； (B) Glycerin, petroleum jelly oil conductive grease ； (C) Silicone oil or silicone grease ； (D) Any insulating paint. 211. The cross section of the stranded wire is 35~50mm2, the diameter of the tied wire is 2.3mm, and the length of the middle tied wire is 50mm, then the length of the joint is (A)mm. (A)350 ； (B)300 ； (C)250 ； (D)400。 212. Steel-core aluminum stranded wire must be reconnected if the ordinary steel core is broken, or the damaged area of the aluminum wire exceeds the area of the conductive part of the aluminum wire (C). (A)30% ； (B)40% ； (C)25% ； (D)10%. 213. When the temperature of the transformer rises, the insulation resistance measurement value (B). (A)increase ； (B)reduce ； (C) unchanged ； (D) increases proportionally. 214. In the neutral point directly grounded system, when a single-phase ground fault occurs, the non-fault phase-to-ground voltage (A). (A) will not increase ； (B) The increase is not obvious ； (C) Increased by 1.73 times ； (D) decrease. 215. For oil-immersed transformers equipped with gas relays, the joint pipe should have a rising slope of (C) of (A) 1% in the direction of the oil conservator. ； (B)2% ； (C)1%～1.5% ； (D)2.5%. 216. After the transformer is filled with vacuum oil, the oil should be replenished (B). (A) Inject from the lower valve of the transformer ； (B) Injection through oil conservator ； Injected from the lower part of the transformer through a vacuum oil filter ； (D) Inject at any time. 217. The air distance between an independent lightning rod and the protected object is generally not less than 5m, and the ground-to-ground distance between the lightning rod grounding device and the grounding grid is not less than (B) (A)5 ； (B)3 ； (C)4 ； (D)6。 218. In 220kV substations in non-high resistivity areas, the grounding resistance of independent lightning rods should not exceed (C)Ω (A)0.5 ； (B)4.0 ； (C)10 ； (D)20。 219. Failure of the synchronization of the circuit breaker and non-all-phase opening and closing operations may cause (A) to occur on the neutral point of the transformer whose neutral point is not grounded. (A)Overvoltage ； (B)Current ； (C)Voltage decrease ； (D) Zero potential. 220. The transformer wiring group is Y, y. When, the neutral current shall not exceed (B) the rated current of the low-voltage winding. (A)15% ； (B)25% ； (C)35% ； (D)20%. 221. The arm of the shaft connected to the upper part of the operating insulator of the GW6-220 isolating switch in the closing position should exceed the dead center (B) mm. (A)3±1 ； (B)5±1 ； (C)4±1 ； (0)6±1. 222. (D) test items are commonly used in the field to judge the insulation condition of equipment. (A)Insulation resistance ； (B)Leakage current ； (C) AC withstand voltage, partial discharge ； (D) Insulation resistance, leakage current, AC withstand voltage, partial discharge. 223. According to the design requirements, the allowable relaxation error of the substation soft busbar is (B) (A) + 6 ； (B)+5%-2.5% ； (C)±5% ； (D)±2%. 224. When the overtravel of the moving contact of the SW6-220 circuit breaker is (B) mm, it can generally be adjusted by changing the depth of the conductive rod screwed into the joint. (A)70±5 ； (B)60±5 ； (C)90±5 ； (D)85±5. 225. The primary closing valve body of the CY5 type hydraulic mechanism has a (B) seal. (A)1 ； (B)2 ； (C)3 ； (D)4。 226. W6-220G type isolating switch closing period is different (B)mm. (A)20 ； (B)30 ； (C)25 ； (D)35。 227. The circuit breaker hydraulic mechanism pipeline assembly connection ferrule should be able to enter the pipe seat smoothly, the pipe head should not bear against the pipe seat, and there should be a gap of (A)mm at the bottom. (A)1～2 ； (B)3 ； (C)4 ； (D)4～5. 228. The following preparations should be made before installing the high-voltage circuit breaker (D). (A)Technical preparation and construction machinery ； (B)Testing instruments and installation materials ； (C) Personnel organization and on-site layout ； (D) Technical preparation, installation materials, construction machinery, testing instruments, personnel organization and site layout, switch inspection, etc. 229. When the hard busbar has both flat bends and twist bends, the twist bends should be twisted first and then flat bends. The total twisted length of the twist bends should not be less than (A) times the width of the busbar. (A)2.5 ； (B)2 ； (C)3 ； (D)4。 230. When checking the aging degree of the insulation of the transformer coil, if it does not crack or fall off when pressed by hand, and the color is darker, the insulation is qualified. This insulation is (B) insulation. (A)Level 1 ； (B)Level 2 ； (C)Level 3 ； (D) Level 4. 231. The main reason for the insulation decline of SF6 circuit breakers and GIS combined electrical appliances is due to the influence of (B). (A)SF6 gas impurities ； (B)Moisture in SF6 ； (C)SF6 specific gravity ； (1)) SF6 equipment insulation parts. 232. After the cooling fan is installed, use a 500V megohmmeter to measure the insulation resistance of the motor and wiring. The value should not be lower than (B) MΩ. At the same time, there should be no swing, jamming, or movement when turning the fan blades by hand. (A)1 ； (B)0.5 ； (C)2 ； (D)10。 233. When the transformer is transported or stored with nitrogen, it must have a pressure monitoring device, and the pressure can be maintained not less than (D) MPa. (A)0.1 ； (B)0.2--0.3 ； (C)0.04 ； (D)0.01--0.03. 234. When replacing the adsorbent of the 70-SFM-32B SF6 circuit breaker, it must be done a short time before (B). (A) The adsorbent sealed package is opened ； (B) Vacuuming ； (C)After vacuuming ； (D) Open the breaking unit and check the contacts. 235. The factors that affect the absorption ratio of the transformer are (B). (A) Quality of iron core and plug-in boards ； (B) Vacuum drying degree, parts cleanliness and exposure time of the device to the air ； (C)Material of coil wire ； (D) Label of transformer oil. 236. The short-circuit grounding wire on the equipment should use soft bare copper wire, and its cross-sectional area should meet the short-circuit current requirements, but not less than (C) mm2. (A)15 ； (B)20 ； (C)25 ； (D)30。 237. In severe weather such as strong winds, heavy rain, and fog of level (B) and above, open-air high-altitude operations should be stopped. (A)5 ； (B)6 ； (C)7 ； (D)4。 238. The core grounding in the power transformer belongs to (B). (A) Working ground ； (B) Anti-static grounding ； (C) Lightning protection grounding ； Protective grounding. 239. When electrical equipment catches fire, you should immediately (A) put out the fire. (A) Cut off the power supply of relevant equipment ； (B) Use a dry fire extinguisher to put out the fire ； (C) Contact dispatch for power outage ； (D) Use a 1211 type fire extinguisher to extinguish the fire. 240. Any work performed at a height (B)m or above above the ground is regarded as high-altitude work. (A)3 ； (B)2 ； (C)2.5 ； (D)1.5. 241. When the hook is in danger of torsional deformation or the cross-section wear reaches the original size (A), it should be scrapped. (A)10% ； (B)5% ； (C)] 5% ； (D)8%. 242. Work can only be done on soft wires with a cross-sectional area not less than (B) Illin2, using bamboo ladders or bamboo poles placed horizontally on the wires. (A)100 ； (B)120 ； (C)95 ； (D)150。 243. When inflating SF6 circuit breakers and combined electrical appliances, their containers and pipes must be dry, and workers must (A). (A) Wear gloves and mask ； (B) Wear gloves ； (C) Wear a gas mask ； (D) Use nothing. 245. Equipment whose voltage to ground is above (B)V is high voltage equipment. (A)380 ； (B)250 ； (C)10kV ； (D)110。 246. For electromagnetic operating mechanism, the closing coil operating voltage should not be lower than the rated voltage (B). (A)75% ； (B)80% ； (C)85% ； (D)90%. 247. In lightning protection measures, the power frequency grounding resistance of an independent lightning rod grounding device is generally not greater than (B)Ω. (A)5 ； (B)10 ； (C)15 ； (D)20。 248. The power frequency grounding resistance of the valve-type arrester grounding device on the substation bus is generally not greater than (A)Ω. (A)4 ； (B)5 ； (C)7 ； (D)10。 249. When the breathing plug of the transformer is equipped with a gasket, before charging (A). (A) The gasket should be removed ； (B) The gasket does not need to be removed ； (C) The gasket can be removed or not ； (D) Gaskets are not considered. 250. There is a three-phase motor whose windings are connected in star shape and connected to a power supply with a line voltage of 380V. When one phase fuse is blown, the voltage between the neutral point of the three-phase winding and the ground is (A)V. (A)110 ； (B)220 ； (C)190 ； (D)0。 251. When lifting, the commander uses (C) to direct the lifting. (A)Gesture ； (B) Mouth flute ； (C) Semaphore ； (D) Gestures and flute. 252. When using a winch to pull the transformer, the inside of the turn of the wire rope is (A), and the staff must pay attention to the stopping position. (A)Danger zone ； (B)Safe zone ； (C) Not dangerous or safe ； (D) You can stay in the attention area. 253. When the screw cap of the lighting fixture is connected to power, (A). (A) The phase wire should be connected to the center contact end ； (B) The neutral line should be connected to the center contact end ； (C)Can be picked up at will ； (D) The phase wire and neutral wire are both connected to the threaded end. 254. When the grounding body round steel is connected to the flat steel, the welding length is (C) times the diameter of the round steel. (A)5 ； (B)3 ； (C)6 ； (D)8。 255. When adding grease to the motor bearing, the grease should be filled (A) 1/2 ； (B)2/3 ； (C)All ； (D)2/5. 256. The grounding body should be connected by lap welding, and the lap length of the flat steel should be (A). (A) Twice the width of the flat steel and welded on three sides ； (B) 3 times the width of flat steel ； (C) 2.5 times the width of flat steel ； (D) 1 times the width of flat steel. 257. Rubber products such as sealing rings can be cleaned with (C). (A)Gasoline ； (B)Water ； (C)Alcohol ； (D) Cleaning agent. 258. The busbar contact surface should be tight. Use a 0.05mmX10mm feeler gauge to check. Busbar widths of 63mm and above must not be inserted into (A)mm. (A)6 ； (B)5 ； (C)4 ； (D)3。 259. The hydraulic mechanism of the circuit breaker should use (A). (A) No. 10 aviation oil ； (B) No. 15 aviation oil ； (C) No. 30 aviation oil ； (D) No. 12 aviation oil. 260. The connection of the grounding body should adopt (A). (A) Lap welding ； (B) Bolt connection ； (C)Butt welding ； (D) Binding. 261. The 25# in 25# transformer oil represents (B). (A) The flash point of transformer oil is 25C ； (B) The freezing point of oil is 25℃ ； (C) The withstand voltage of transformer oil is 25kV ； (D) The specific gravity of transformer oil is 25. 262. Among the following factors (A) has the greatest influence on the dielectric strength of transformer oil. (A)Moisture ； (B)Temperature ； (C)Impurities ； (D) Specific gravity. 263. The explosion-proof membrane of the transformer explosion-proof device will break when the pressure reaches (B)kPa. (A)40 ； (B)50 ； (C)60 ； (D)45。 264. The contents of the transformer overhaul project include (D). (A) Clean the dirt in the oil pillow and check the oil level gauge ； (B) Maintenance and painting of fuel tanks and accessories ； (C) Maintenance of cooler safety airway and its protective film ； (D) Inspect the body of the machine. 265. When the insulation resistance of the primary winding of the current transformer is lower than (C) or less of the previous measurement value, or t86 is greater than the specified value, it should be dried. (A)80% ； (B)60% ； (C)70% ； (D)50%. 266. The upper pressing plate that fixes the hard busbar fittings is made of aluminum alloy. If it is damaged or lost, it can be replaced by (D). (A)Iron plate ； (B)Cast iron ； (C)Iron alloy ； (D) Aluminum plate. 267. In the lower oil bowl of the breather on the diaphragm oil conservator of the power transformer (B). (A) Drain oil ； (B) No oil ； (C) It doesn’t matter whether you add oil or not. ； (D) There is no oil to put in. 268. The static contacts of the SNl0-10 type circuit breaker are newly installed. Check that the closed diameter of the static contacts is less than (B) and should be dealt with. (A)18．4mm ； (B)18.5～20mm ； (C)20． Im ； (D) 20.2~20.3 269, SNl0-10 type circuit breaker conductor rod stroke can be adjusted by increasing or decreasing (A). (A) Limiter gasket ； (B)Insulating gasket ； (C)Insulated tie rod ； (D) Buffer rubber pad. 270. After the SNl0-10 type circuit breaker is overhauled, use a 2500V megohmmeter to measure the insulation resistance value. If the value is greater than (A) MΩ, it is qualified. (A)300 ； (B)500 ； (C)700 ； (D)1000。 271. When the ablation depth of the copper-tungsten alloy part of the moving contact of the SNl0-10 circuit breaker is greater than (C)mm, it should be replaced ； When the ablation depth of the conductive contact surface is greater than 0.5mm, it should be replaced. (A)1 ； (B)1.5 ； (C)2 ； (D)0.5. 272. The iron core push rod of CD10 type electromagnetic mechanism should be able to continue to rise (A) mm when it touches the connecting plate. (A)8-10 ； (B)7 ； (C)11 ； (D)7～7.9. 273. When measuring the insulation resistance of power cables of lkV and above, (C) should be used. (A)500V megger ； (B)100V megger ； (C)2500V megger ； (D) 1000V megger. 274. Flexible conductors above 35kV in outdoor power distribution devices adopt (C). (A) Stranded copper wire ； (B) Stranded aluminum wire ； (C) Steel core aluminum stranded wire ； (D)Steel core multi-stranded wire. 275. The arc extinguishing medium of vacuum circuit breaker is (C). (A)Oil ； (B)SF6 ； (C)vacuum ； (D)Air. 276. The conductive contact surface of the static contact of the SNl0-10 type circuit breaker should be smooth and flat. If the burn area reaches (A) and the depth is greater than 1mm, it should be replaced. (A)30% ； (B)20% ； (C)25% ； (D)40%. 277. The overlapping surface of hard busbars should be processed flat and without oxide film. The processed cross-section should be reduced. The copper busbar should not exceed 3% of the original cross-section, and the aluminum busbar should not exceed (C) of the original cross-section. (A)3% ； (B)4% ； (C)5% ； (D)6%. 278. Parallel capacitor equipment should be replaced when (C) occurs. (A) The dust accumulation is relatively large ； (B) There is no breakdown in the fuse blown capacitor ； Capacitor deformation, expansion and leakage ； (D) The capacitor terminal wiring is poor. 279. When the current transformer is working normally, the secondary circuit is OK (B). (A)Open the way ； (B)Short circuit ； (C) Install fuse ； (D) Connect an infinite resistor. 280. When measuring the DC resistance of the primary circuit increases significantly, you should (C). (A) Pay attention and observe ； (B)Continue running ； (C)Inspection and processing ； (D) Not considered. 281. (C) should be carried out when the 10kV circuit breaker has serious defects that affect the continued safe operation of the circuit breaker. (A)Overhaul ； (B) Minor repairs ； (C) Temporary maintenance ； (D) Strengthen supervision. 282. The grounding metal shell of the circuit breaker should be equipped with (B) a grounding screw with a diameter of not less than 12mm and having good conductive properties. (A) rusty ； (B) Rust prevention ； (C) Rust-free ； (D) Roughly made. 283. When the acid value (B) of the transformer oil is found, the adsorbent in the oil purifier should be replaced in time. (A)Fall ； (B) rise ； (C) unchanged ； (D) Unclear. 284. The arc extinguishing and insulating medium of SF6 circuit breaker is (D). (A)Insulating oil ； (B)Vacuum ； (C)Air ； (D) Sulfur hexafluoride. 285. Since the isolating switch does not have a special (B) device, it cannot be used to connect the load current and cut off the short-circuit current. (A)Quick mechanism ； (B) Arc extinguishing ； (C) closed ； (D) Insulation. 286. For electromagnetic operating mechanisms, the operating voltage of the trip coil should not be higher than the rated voltage (C). (A)55% ； (B)75% ； (C)65% ； (D)30%. 287. GW5 type isolating switch, when the operating mechanism drives one insulator column to rotate (C), the other insulator rotates in the opposite direction through the rotation of the gear. (A) 45° (B) 60° (C) 90° (D) 180° 288, 35kV indoor, 10kV and below indoor and outdoor busbars and multi-component insulators, when conducting insulation resistance tests, each component must be not less than 1000MΩ. If it is lower than (C)MΩ, it must be replaced. (A)250 ； (B)400 ； (C)300 ； (D)500。 289. When operating the circuit breaker, the variation range of the control bus voltage is not allowed to exceed 5% of its rated voltage, and the independent main closing bus voltage should maintain the rated voltage (A). (A)105%～110% ； (B)110% or more ； (C)100% ； (D) Within 120%. 290. When only one motor is running in the circuit, the rated current of the melt is ≥ (C) times the rated current of the motor. (A)1.4 ； (B)2.7 ； (C)1.5～2.5 ； (D)3。 291. The fuse melt should have (D). (A) Low melting point and poor electrical conductivity ； (B) Good electrical conductivity and high melting point ； (C) Easy to oxidize, low melting point ； (D) Low melting point, good electrical conductivity, and not easily oxidized. 292. The mechanical strength of insulating materials generally increases with temperature and humidity (C). (A) Increase ； (B) unchanged ； (C)Fall ； (D) Little impact. 293. The temperature indicated by the transformer thermometer is (A). (A) Upper oil temperature ； (B)Iron core temperature ； (C) Winding temperature ； (D) Middle oil temperature. 294. When the circuit breaker is connected to the horizontal transmission tie rod, the shaft pin should be (C). (A)Vertical insertion ； (B) Insert randomly ； (C) Horizontal insertion ； (D) 45° insertion. 295. When the circuit breaker is connected to the porcelain bushing flange, the compression amount of the rubber seal used should not exceed its original thickness (B). (A)1/5 ； (B)1/3 ； (C)1/2 ； (D)1/4. 296. The weight of silica gel in the transformer oil purifier is the mass of the transformer oil (A). (A)1% ； (B)0.5% ； (C)10% ； (D)5%. 297. When the transformer is filled with vacuum oil, the required oil filling speed is (D). (A)10t/h ； (B)20t/h ； (C)25t/h ； (D)50t/h. 298. When starting multiple motors, (A) should be used. (A) Start each unit one by one according to capacity from large to small. ； (B) Randomly start one by one ； (C) Start each unit one by one according to capacity from small to large. ； (D) Start in position sequence.