Specifications for Digital Labeling of Electrical Secondary Circuits

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This post was last edited by yunrun on 2018-5-15 at 17:58. To facilitate the installation, maintenance, and testing of electrical secondary circuits, various numerical labels must be assigned to them in the circuit layout diagram, depending on their respective functions. The digital labels in the secondary circuit are divided into those for DC circuits and those for AC circuits; it is important to assign digital labels to electrical circuits correctly. Digital numbering in the secondary circuit: yunrun.com.cn/tech/1962.html
1. Range of digital numbers for DC secondary circuits
For DC circuits with different functions, their digital number groups are shown in Table 1.

Table 1: Digital Number Groups for DC Circuits
| Circuit Name | Digital Group (I) | Digital Group (II) | Digital Group (III) | Digital Group (IV) | Remarks |
|---------------|------------------|-------------------|---------------------|---------------------|---------|
| Positive power supply circuit | 1 | 101 | 201 | 301 | |
| Negative power supply circuit | 2 | 102 | 202 | 302 | |
| Closing circuit | 3–31 | 103–131 | 203–231 | 303–331 | |
| Circuit for monitoring the power supply of the green light or closing relay | 5 | 105 | 205 | 305 | See Note 1 |
| Tripping circuit | 33–49 | 133–149 | 233–249 | 333–349 | |
| Circuit for monitoring the power supply of the green light or closing relay | 35 | 135 | 235 | 335 | See Note 1 |
| Backup power supply closing circuit | 50–69 | 150–169 | 250–269 | 350–369 | See Note 2 |
| Position signal circuit for switchgear | 70–89 | 170–189 | 270–289 | 370–389 | |
| Sound circuit for emergency tripping | 90–99 | 190–199 | 290–299 | 390–399 | |

Circuit Name | Digital Number Group
---|---
Unit automatic control circuit | 401–599
Protection circuit | 01–099 (or J1–J99)
Generator excitation circuit | 601–699
Signal circuit | 701–799
Backup | 800–870
Closing coil circuit | 871–879
Isolator and switch operation interlock circuit | 88–899
Warning signals and individual signals | 901–949
Command signals | 950–989
Turbine phase-regulating servo motor | 990–999

Note 1: For the red or green light circuits within the switch control circuit, if they are connected directly from the control cable, such circuits can be used with the same numbering scheme as those in the control circuit’s power supply system ； Note 2: In installation sites where a backup power supply does not engage automatically, the numbers 50–69 marked on the wiring diagram can be used as identifiers for other circuits. However, when there are not enough numbers available for circuit identification, these numbers can be decreased sequentially. When assigning numerical identifiers to DC circuits, the following points should be taken into account: ① In a circuit, if the polarity changes after passing through major voltage-reducing components (such as coils or resistors), the polarity of the circuit identifier should also change accordingly. ②For the segments whose polarity needs to be changed during operation (such as changing the polarity of the armature connections in DC motors to reverse their direction of rotation), and those whose polarity cannot be clearly specified (such as the connection segments between two or more resistors, coils, and other components), odd or even numbers can be assigned arbitrarily. ③When several circuit breakers are installed, the numbering of the control circuits for each circuit breaker should generally correspond to the \"numeric sequence\" of the alphanumeric codes for those circuit breakers. For example, for a circuit breaker labeled “QF”, the control circuit label uses 1-99 ； For the circuit breaker labeled “1QF”, the control circuit labels are 101-199, etc. ④For the numbering of the circuit control circuits for circuit breakers, it should be assigned in sequence within each numerical range allocated to it. For circuits with dedicated designations, such as the green light for the circuit that controls breaker closing or the circuit of its monitoring relay, whose designation is 5 (105, 205...), and the red light in the tripping circuit or the circuit of its monitoring relay, whose designation is 35 (135, 235...), these can be labeled using the respective dedicated designations. 2. Range of digital numbers for AC secondary circuits: For AC circuits with different purposes, the groups of digital numbers for these circuits are shown in Table 2.
Table 2: Groups of Digital Numbers for AC Circuits
Circuit Name | Purpose | U-phase Number Group | V-phase Number Group | W-phase Number Group | Neutral Line Number Group | Ground Wire Number Group
—— | —— | —— | —— | —— | —— | ——
Current circuits for protection devices and measuring instruments: TA | U401-U409 | V401-U409 | W401-U409 | N401-U409 | L401-U409
Current circuits for protection devices and measuring instruments: 1TA | U411-U419 | V411-U419 | W411-U419 | N411-U419 | L411-U419
Current circuits for protection devices and measuring instruments: 2TA | U421-U429 | V421-U429 | W421-U429 | N421-U429 | L411-U429
Current circuits for protection devices and measuring instruments: 9TA | U491-U499 | V491-U499 | W491-U499 | N491-U499 | L491-U499
Current circuits for protection devices and measuring instruments: 10TA | U501-U509 | V501-U509 | W501-U509 | N501-U509 | L501-U509
Current circuits for protection devices and measuring instruments: 19TA | U591-U599 | V591-U599 | W591-U599 | N591-U599 | L501-U599
Voltage circuits for protection devices and measuring instruments: YH | U601-U609 | V601-U609 | W601-U609 | N601-U609 | L601-U609
Voltage circuits for protection devices and measuring instruments: 1YH | U611-U619 | V611-U619 | W611-U619 | N611-U619 | L611-U619
Voltage circuits for protection devices and measuring instruments: 2YH | U621-U629 | V621-U629 | W621-U629 | N621-U629 | L621-U629
Circuit Name | Purpose | U/V/W-phase Number Group | Neutral Line Number Group
Voltage circuits switched via isolator auxiliary contacts or relays: 6–10 kV | U(V, W)760–769 | N600
Voltage circuits switched via isolator auxiliary contacts or relays: 35 kV | U(V, W, L)730–739 | N600
Voltage circuits switched via isolator auxiliary contacts or relays: 110 kV | U(V, W, L, S)710–719 | N600
Circuit Name | Purpose | U-phase Number Group | V-phase Number Group | W-phase Number Group | Neutral Line Number Group
Common circuit for insulation test voltmeters | U700 | V700 | W700 | N700
Common current circuit for bus differential protection: 6–10 kV | U360 | V360 | W360 | N360
Common current circuit for bus differential protection: 35 kV | U330 | V330 | W330 | N330
Common current circuit for bus differential protection: 110 kV | U310 | V310 | W310 | N310
Signal circuits for control and protection: U1–U399 | V1–V399 | W1–W399 | N1–N399
Note: The common current circuits for bus differential protection may be labeled using the numbers 301–399 from the AC control circuits. Eight typical applications of high-value selectors and low-value selectors: yunrun.com.cn/tech/1974.html. When assigning numerical labels to communication circuits, the following points should be taken into account: ① The labels for current transformer and voltage transformer circuits should start from the output terminals of the transformers, and be assigned in sequence within the designated range of numerical labels. Specifically, the circuit numbers are labeled in groups of 10 digits; for example, the circuits for three-phase current transformers are U401-U409, V401-V409, W401-W409, etc. ②The digital numbering groups used for current transformers and voltage transformers should correspond to the “digital sequence numbers” preceding their alphanumeric symbols; for example, the circuit numbering for current transformer 1TA is 411-419, etc.