What documents should the electrical engineering department produce during the preliminary design phase?

You can check the Basic Design Specifications of the Ministry of Chemical Industry, or the Requirements for the Depth of Basic Design in Sinopec. 11 Power Supply and Distribution 11.1 Introduction 11.1.1 Design basis and standards and specifications adopted in the design. 11.1.2 Scope of design and division of labor. 11.1.3 Power Supply Status: An overview of the locations and distances of the power plants and regional substations related to this project, the installed capacity of the equipment, the main system connections, the number of power supply sources available, the conditions for adding new users, as well as the short-term and long-term short-circuit capacities. If it is a renovation of an existing factory, it is also necessary to explain the current status of the factory’s power supply system. If there is a self-provided power station, it also needs to be specified. 11.1.4 The load requirements for power consumption and the design load requirements on the power supply side of the plant’s substations, as well as those for workshop substations and transformer selection, are shown in Tables 11.1.4–1 and 11.1.4–20. Verify the starting voltage level of large motors, and explain the measures to limit voltage drops as well as the final selection of the main transformer capacity. It outlines the performance requirements for power factor compensation, as well as the capacity and methods used for compensation. • It explains what the load levels at stage 1, stage 2, and stage 3 are across the entire plant, the power supply requirements for each level and the solutions to meet those requirements, including the provision of emergency power sources. Table 11.1.4-1: Load Calculation Table for XX kV of the Main Substation and Distribution substations
Serial Number | Name of Electrical Equipment | Number of Units Installed | Equipment Capacity | Required Capacity | Remarks | Normal Use | Backup | Total Capacity (kW) | Normal Capacity (kW) | PP (kW) | Qp(kVAR) | Sp(kVA)
× × Motors × × × × × × × For synchronous generators, Qp represents the load value -------------------- × × × × × × × × Substation × × × × × × -------------------- × × × × × × Capacitor compensation – × Total × × × × × × × Losses of main transformer × × Losses of reactors × × Total load on the power supply side × × × Overall power factor of the plant should be greater than 0.5 Selection of main transformer: × units, × × kVA Capacity of on-site power generation station × × × Number of generators: × units, × × kW Loads that require power from the external grid due to insufficient supply × × × 11.1.5 Overview of the plant’s power supply system: Capacity of the selected main substation or on-site power generation station, characteristics of the main wiring, input voltage of the plant, and selection of voltage levels for various distribution stages. An overview of the number, capacity, and technical and economic feasibility of secondary distribution substations and workshop transformer stations. For larger or more complex projects, technical and economic comparisons of multiple alternatives are also required. It describes the construction plans for various substations and power distribution stations, the configuration principles, as well as the control, signaling, and metering methods. Explain the calculated results of short-circuit current. 11.1.6 Selection of critical equipment: All high and low voltage electrical equipment and cables are selected based on load requirements, environmental conditions, voltage levels, economic current density, or breaking capacity, and are verified for dynamic and thermal stability under short-circuit conditions. Table 11.1.4—2: Table of Load and Transformer Selection for Workshop Substations
Serial Number | Workshop and Electrical Equipment/Machine Names (listed by different operating modes) | 6(10) kV Power | 380 and 220 V Power and Lighting | Design Apparent Capacity (kVA) | Remarks
| Power | Lighting (kW) | Equipment Capacity (kW) | Required Capacity | Equipment Capacity (kW) | Required Capacity | kW | kVAR | kW | kVAR
1 | Workshop 1 | 1.1 | × | × | × | × | × | × | × | × | 1.2 | …… | × | × | × | × | × | × | 1.3 | …… | × | × | × | × | × | Workshop subtotal | × | × | × | × | × | ×
2 | Workshop 2 | 2.1 | × | × | × | × | × | × | × | × | 2.2 | …… | × | × | × | × | × | × | 2.3 | …… | × | × | × | × | × | Workshop subtotal | × | × | × | × | × | ×
(The same applies to other workshops.) | Total for Workshops 1–n | × | × | × | × | Multiply by active and reactive power simultaneity factors | × | × | × | × | × | × | % Loss of Transformer | × | Select transformers: × units, each with × × kVA (× × × kVA + × × × kVA)
11.1.7: Type of Main Substation – Explain the basis and reasons for choosing an indoor or outdoor type; provide, where possible, the pollution level standards established by the power supply authorities. 11.1.8 Relay protection and automatic devices for main power equipment and lines 1 Describe separately the methods employed for relay protection according to the protection objects of each inlet and outlet circuit. 2 Automatic devices used in high-voltage systems and their performance requirements. 3 Settings and requirements for the microcomputer monitoring and protection system of the electrical system. 11.1.9 Overvoltage Protection for Electrical Equipment: Explains the objects subject to overvoltage protection and the measures taken. Measures for protecting electrostatic capacitors and against operational overvoltages in high-voltage switches, as well as measures to eliminate the higher harmonic voltages generated by electrical equipment with nonlinear loads. 11.1.10 Explanation of the neutral grounding methods in medium-voltage systems, as well as the situation regarding system capacitive current and compensation measures. 11.1.11 Operating Power Supply and DC System: Describes the operating power supplies used in the main substation and secondary high-voltage distribution stations, as well as the capacity and quantity of the main DC-powered equipment. There should be a calculation of the DC load, or determination of the normal load and fault load data. 11.1.12 Environmental Characteristics of Production Units and Selection of Power Distribution Materials: Describe the environmental characteristics of each production unit, and select power distribution equipment and materials such as standard, explosion-proof, dust-proof, corrosion-resistant, and waterproof types according to those characteristics. 11.1.13 Operation and protection of power supply for mechanical drive: The operation and protection of the power supply for mechanical drive are configured in accordance with the requirements of process production for drive control. 11.1.14 Lighting: It shall be specified separately for lighting in production facilities and road lighting. 11.1.15 Distribution Lines: Describe the models and specifications of the distribution lines used within the plant, as well as the methods and principles for their installation. 11.1.16 Anti-static, lightning protection, and grounding 1 Describe the measures for anti-static protection. 2 Explain the requirements for grounding and neutral connection of electrical equipment. 3 Draw an “explosion hazard zone classification diagram” based on the characteristics of the workshop environment, and indicate the lightning protection measures adopted. 4. Specify the various ground resistance values used as well as the common ground resistance value, the material and specifications of the grounding grid, and its installation requirements. 11.1.17 Main energy-saving measures, as well as the use of new technologies, materials, and equipment. 11.1.18 Staffing table (see Table 4.1.7 in the chapter on “Chemical Processes and Systems”). 11.1.19 Existing problems and suggestions for solutions. 11.2 Tables 11.2.1 List of Major Equipment The major equipment generally includes various key electrical components in the main distribution (main supply) system and those in the primary circuits of on-site power plants, complete power supply and distribution units, microcomputer-based monitoring and protection devices for electrical systems, control and protection panels along with their DC-related equipment, emergency power supply units, workshop transformers in each workshop, low-voltage distribution panels (cabinets), lighting distribution boxes (posts), as well as other non-standardized major equipment. The general order of the items in the table is: transformers, reactors, high-voltage circuit breakers and their operating mechanisms, high-voltage isolators and their operating mechanisms, instrument transformers, arresters, capacitors and harmonic suppression devices, high-voltage complete power distribution equipment, low-voltage complete power distribution equipment, DC equipment, secondary circuit panels, and custom-made equipment. 11.2.2 List of Main Materials The main materials generally include: high and low voltage power cables, control cables, wires, common steel materials, non-ferrous metals, cable trays, etc. The contents of the above tables should include serial number, name, model and specifications, unit, quantity, and remarks. 11.3 Diagrams Paper 11.3.1 Overall high-voltage system diagram of the plant. 11.3.2 General layout of high and low voltage power supply throughout the plant. 11.3.3 Plan layout of the main substation (power distribution station). 11.3.4 Diagram of explosion hazard zone classification. The graphics, symbols, and annotations in the aforementioned drawings are all in accordance with the standards for **“electrical symbols”**. 11.4 Self-provided power stations, rectification stations, and electric furnace substations 11.4.1 Self-provided power stations 1 Instructions 1) Reasons for installing a self-provided power station. 2) Unit type, selection, capacity, voltage. 3) Synchronization point setting and synchronization method. 4) Wiring system, operating mode. 5) Voltage regulation method. 6) Unit relay protection and other automatic devices. 7) Operating power supply. 8) Signal system. 9) Plant power supply system. 10) Quota. 11) Existing problems and suggestions for solutions. 2 Equipment and material list. 3 Drawings 1) Layout plan of the control room. 2) Layout plan of the generator room and plant power supply (can be included in the thermal process layout plan). 11.4.2 Rectifier Station 1 Instructions 1) General Overview: Describe the production process and the nature of the load, the scale of production, the type of tanks, the number of operating units and the total number of units, the tank pressure and current density, the requirements related to the production characteristics, as well as future development plans. 2) Selection of the rectification unit (including the rectifier transformer): Specify the type of rectification equipment, the type of rectification, as well as the rectification voltage, current, and number of units. 3) Wiring method and structural features. 4) Cooling system: Describe the cooling method, the medium and the required quality, the preparation and supply of the medium, as well as the selection of equipment. 5) Selection of the one-time wiring system and supply voltage. 6) Voltage regulation range and voltage regulation method. 7) Category, range, grade, step voltage. 8) Overall and partial voltage regulation as well as automatic voltage regulation status. 9) Explanation of the protection for the rectifier unit and relay protection. 10) Self-use power and operating power for the rectifier station. 11) Measurement signals and connection requirements. 12) Busbar selection: Explanation of material and cross-sectional area selection. 13) Rectifier station configuration, building and structure conditions, and special requirements (temperature, humidity, ventilation). 14) Quota. 15) Existing problems and suggestions for solutions. 2 List of equipment materials 3 Drawings 1) Rectifier station system diagram. 2) Layout plan of the rectifier station. 3) When there are special requirements, draw a schematic diagram of the automatic adjustment circuit. 11.4.3 Electric Furnace Substation 1 Instructions 1) Furnace type, production scale, capacity, number of phases, operating hours. 2) Determination of the power supply voltage (as already explained in the plant’s power supply system, it may not need to be listed here). 3) The capacity of the electric furnace transformer, the rated currents and voltages for the primary and secondary sides, the regulation range and method as well as the number of stages, the wiring configuration, the cooling method, etc. 4) The brief description outlines the configuration, material selection (including flexible cables), cooling method, burn-through mechanism, and busbars. 5) Control methods for adjusting the elevation of the electrodes and applying pressure to them (when controlled by a microcomputer, explain the relationship between the program operations and the input parameters). 6) All power and operating power supplies. 7) Power factor, voltage balance compensation, and measures to prevent harmonic interference. 8) Relay protection and automatic devices. 9) Plan layout. 10) Quota. 11) Existing problems and suggestions for solutions. 2 List of equipment materials 3 Drawings 1) System diagram (not drawn separately if it is already included in the plant’s high-voltage power supply system). 2) Floor plan of the electric furnace substation. 3) Schematic diagram of the control block for automatic adjustment (or microcomputer program control).