ELECTRIC, WITH AN EDGE

Main Electrical Wiring of 110kV Substation

It is connected with various high-voltage electrical equipment, mainly responsible for receiving or distributing electric energy, reflecting the connection mode, interaction and loop relationship between various high-voltage equipment, and it is an important electrical part of 110kv substation.

The performance of the main wiring has a direct impact on the flexibility and reliability of the operation of the substation, and determines the selection of control methods and automatic devices in the power transmission and transformation process, as well as the arrangement of relay protection and power distribution devices.

Therefore, when choosing the main wiring of the 110kv substation, in addition to its own power supply reliability, economy and quality issues, it is also necessary to pay attention to factors such as the expansion and operation of the substation.

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Table of Contents
110kV Substation
110kV Substation

Considerations when choosing electrical main wiring

  • There are several types of substations: regional substations, enterprise substations, hub substations, branch substations and terminal substations. Different characteristics and functions make the requirements for the main electrical wiring different.
  • For short-term and long-term development scales, the choice of main wiring needs to be consistent with the 5-10 year power development plan.
  • Considering the influence of the number of main transformers, the number of main transformers in a substation directly affects the electrical main wiring, and different transmission capacities have different requirements for the flexibility and reliability of the main wiring.
  • Consider the impact of load classification and number of outgoing lines. The first-level load needs two independent power supplies. If one of them does not work, all the first-level loads must be continuously powered; the second-level load usually also requires two power supplies. When one of them does not work, most of them must be ensured. The secondary load continues to supply power; the tertiary load often only needs one power supply.
  • Considering the impact of the reserve capacity, the reserve capacity is mainly to adapt to the sudden increase in load, maintain reliable power supply, and prevent emergency situations such as maintenance of equipment and outages.

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Selection of electrical main wiring requirements

  • Reliability of power supply. Reliability is directly related to the production and distribution of electricity. The evaluation criteria for whether the main wiring is reliable or not can provide continuous power supply generally: When the circuit breaker is overhauled, it has little impact on the power supply of the system; try to prevent the occurrence of all substation outages; If the busbar fails, the number of outages of the main transformer and the number of outage circuits should be minimized, and the normal power supply of important users should be ensured as much as possible.
  • Flexibility in operation and maintenance. In the dispatching operation, it should be possible to flexibly remove or invest the lines and transformers to realize unattended substations, and try to meet the system dispatching requirements during faults, maintenance and special operations; pay attention to safety during maintenance, and try not to affect the operation of the power grid On the premise of supplying power to the user, the bus, circuit breaker and relay protection equipment can be shut down conveniently and quickly.
  • Scalability and adaptability. Adapt to unexpected load surges in a certain period of time to meet power supply needs. When expanding, it can adapt to the transition from initial wiring to final wiring.
  • Economic rationality. On the basis of flexibility and reliability, the main wiring should be as economical and reasonable as possible. For example, the investment province, including the equipment purchase cost of the substation, construction engineering cost, installation engineering cost and other costs, the wiring method is different, the investment is also very different; the area is small, the main wiring is mainly designed for the power distribution device , The wiring method is different, the area of ​​the power distribution device is also different; the energy loss is small.

The key to electrical main wiring

Selection of power distribution device

The 10kV power distribution device mainly has two layout forms: outdoor and indoor. The exterior layout can be divided into exterior high layout, exterior half height layout and exterior medium layout.

The high-type layout is more suitable for double bus bars, and the layout form is to overlap the bus bar and the bus bar isolation switch up and down.

The half-height arrangement is to raise the bus bar and the bus bar isolation switch, and directly arrange current transformers and circuit breakers and other equipment under the raised bus bar to reduce the span size of the power distribution device. Larger horizontal area.

Therefore, this arrangement is mostly used in substations with many incoming and outgoing circuits.

The outdoor medium-sized layout is to install all equipment and electrical appliances on the ground equipment support, but there is no equipment layout under the busbar. This method is clear, reliable, not easy to misoperation, low cost, low frame height, and convenient construction and maintenance.

Related electrical equipment and typical wiring methods

The main wiring of the substation should have the following electrical equipment: main transformer, circuit breaker, bus bar, isolating switch, relay protection device, voltage transformer, current transformer, span, lightning arrester, etc.

When designing and selecting the electrical main wiring of 110kV substations, the intermediate substations and terminal substations are the main considerations.

The terminal substation is close to the load center. The 110kV incoming line is usually two-way incoming line, and two main transformers are used to distribute power to low-voltage users;

On the basis of ensuring reliable power supply, the main wiring of the substation shall minimize the area occupied to meet the requirements of simplification, automation, standardization and unmanned.

The selection and design of the main wiring should be determined according to many factors such as the characteristics of electrical equipment, the nature of the load, and the strength of the superior power grid.

Terminal substation wiring forms usually include transformer group wiring, internal bridge wiring, and external bridge wiring.

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