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The main electrical connection refers to the connection method of electrical equipment from generators, transformers to distribution devices and loads in the power system. It is the core part of the power system, ensuring that electric energy can be effectively transmitted, distributed and controlled. The quality of the main connection design directly affects the operating reliability, economy and safety of the system.
1. The role of the main electrical connection
1. Electric energy collection and distribution: The electric energy from the power plant or substation is transmitted to each load center through transformers and transmission lines, and the power is distributed according to demand.
2. System protection and switching: By configuring electrical equipment such as circuit breakers and disconnectors, the system is protected from faults, and switched to the backup line in the event of a fault to ensure the continuous operation of the system.
3. Dispatching and control of the power system: The main electrical connection is the basis for the operation and dispatching of the power system, and a reasonable wiring structure contributes to the stable operation of the power system.
2. Basic requirements for electrical main wiring
1. Reliability: The system should be able to operate safely and reliably under normal and fault conditions. In case of a fault, the faulty part can be quickly cut off to keep the rest of the parts powered normally.
2. Flexibility: The main wiring should be easy to operate and maintain, and can flexibly switch different power supplies and loads in the system.
3. Economy: The wiring method should be as simple as possible, reduce equipment investment and floor space, and meet the system operation requirements.
4. Scalability: The main wiring design should take into account the needs of future system expansion and have a certain degree of scalability.
3. Common types of electrical main wiring
Common types of electrical main wiring include the following:
1. Single busbar wiring
2. Single busbar segmented wiring
3. Double busbar wiring
4. Double busbar segmented wiring
5. Ring wiring
6. Circuit breaker and half busbar wiring
4. Configuration of switchgear
Common switchgear in main wiring include:
1. Circuit breaker: used to connect or disconnect the circuit, and can automatically cut off overload, short circuit or other fault current.
2. Isolating switch: used to isolate the power supply and ensure the safety of operators during overhaul or maintenance. It cannot be operated under load.
3. Load switch: used to connect and disconnect circuits under load, suitable for medium and low voltage distribution systems.
4. Grounding switch: used to ground when overhauling electrical equipment to prevent the risk of electric shock caused by induction electricity or accidental closing.
V. Characteristics and scope of use of single busbar wiring
1. Characteristics of single busbar wiring
- Structure: All power equipment (such as generators, transformers, loads, etc.) are directly connected to one busbar through a circuit breaker.
- Simplicity: Single busbar wiring has a simple structure, less equipment, lower investment, and easy operation and maintenance.
- Unreliability: The entire system depends on one busbar. If the busbar or circuit breaker fails, the entire system may lose power supply, and the reliability during failure is low.
- Operability: The operational flexibility is poor, and switching or overhaul during system operation requires disconnecting the entire system.
2. Scope of use
- Applicable occasions: Single busbar wiring is usually suitable for occasions with small loads and low requirements for power supply reliability, such as small substations, power distribution systems of industrial and mining enterprises, etc. It can also be used in power plants or substations with small loads and simple operations.
VI. Characteristics and scope of use of single busbar segmented wiring
1. Characteristics of single busbar segmented wiring
- Structure: The busbar is divided into two or more independent segments by a circuit breaker or busbar coupler, and each segment can operate independently. Usually two busbar segments are connected by a circuit breaker (called a busbar coupler).
- Improved reliability: Compared with single busbar wiring, segmented wiring can cut off the faulty part when a certain section of the busbar fails, and maintain normal power supply to other sections, thereby improving the reliability of the system.
- Increased flexibility: The busbar segmented wiring structure allows the system operation mode to be switched when equipment is overhauled or maintained without disconnecting the entire system.
- Moderate cost: Compared with double busbar wiring, the busbar segmented wiring structure is less complex and less costly, and has a significant improvement in reliability.
2. Scope of use
- Applicable occasions: Single busbar segmented wiring is often used in medium-sized substations or occasions with certain requirements for power supply reliability, such as medium-sized industrial enterprises, urban power distribution systems, etc. In such occasions, power supply reliability is more important, and busbar segmentation can effectively reduce the scope of power outages caused by busbar failures.
VII. Summary
The main electrical connection plays a key role in the power system. Reasonable wiring design can improve the reliability, flexibility and economy of the system. Common wiring methods include single busbar wiring, single busbar segmented wiring, double busbar wiring, etc. Single busbar wiring has a simple structure and good economy, but poor reliability, and is suitable for small load occasions. Single busbar segmented wiring significantly improves the system reliability and operational flexibility by adding busbar segments and busbar couplers, and is suitable for medium loads and occasions with high power supply reliability requirements.
