Application of relay protection in power system

3.3 Control loop defects

Control circuit defects mainly occur in the operating circuit of the circuit breaker. The secondary wiring involves many components and locations, mainly composed of control handles, indicator lights, operating boxes, circuit breaker mechanism tripping and closing coils, auxiliary contacts and phase locking circuits. Control circuit defects generally occur when the equipment stops supplying power, protection is activated, automatic switching devices or reclosing devices are activated. The main reasons are as follows:

(1) There are problems in the design of the operating circuit principle or wiring, which were not discovered during the operation of the equipment;

(2) The handle fails to operate properly and the indicator light is broken;

(3) The locking circuit contacts are abnormal;

(4) The main contacts of the circuit breaker do not match the secondary auxiliary contacts;

(5) There is a problem with the circuit breaker operating mechanism;

(6) There is a problem with the automatic switching device or the reclosing circuit;

(7) Human error in operation causes the protection device to malfunction or fail to operate.

3.4 Prevention of defects

Preventive measures should be taken to ensure that the equipment is in good condition and prevent defects from occurring, including equipment modification, protection calibration, daily maintenance and countermeasures. Secondly, a summary and analysis should be made for each defect, experience should be accumulated, and similar defects should be prevented from occurring again. Thirdly, defects that occur during operation must be eliminated quickly and safely. When the device has many defects, is overdue in service, and its functions do not meet the requirements of the power grid for 110 kV and 220 kV line protection, the microcomputer line protection should be replaced in time to ensure the normal operation of the protection device and improve the stability of the system.

In addition, on-site staff need to continuously improve their technology and skills, and enhance their ability to prevent and handle defects.

4 Use and maintenance of relay protection devices

The importance of relay protection devices lies not only in whether they meet the requirements of basic operating conditions when selecting them, but also in doing a good job in daily inspection and maintenance.

First, we need to fully understand the initial status of the equipment. The initial status of the relay protection equipment affects its normal and effective operation in the future. Therefore, we must pay attention to collecting and organizing equipment drawings, technical information, and operation and test data of related equipment. For the daily maintenance of the equipment, we must pay attention to each link in the equipment life cycle and manage the whole process.

Secondly, timely and comprehensive statistical analysis of equipment operation status data is required. First, the characteristics and rules of equipment failures must be understood, and then the part and time of the failure can be pre-judged and analyzed through the analysis of daily data of the operation status of the relay protection device, and timely troubleshooting can be carried out before the failure occurs. The safety factor and service life of the protection device can be improved to ensure the normal operation of the power system.

Thirdly, we need to understand the development trend of relay protection technology and adopt new technologies to supervise and maintain the equipment. With the rapid development of the power system, the continuous upgrading of relay protection equipment, and the imperfection of relay protection equipment, we must strengthen the application of new technologies. Only in this way can we ensure the scientific and effective protection devices, and thus play their due role in the protection of the power system.

5 Development prospects of relay protection technology

The application prospects of relay protection technology in power systems are mainly reflected in the following aspects:

5.1 Further expansion of relay protection functions

With the widespread use of computers and the help of computer-aided design functions, the functionality of relay technology will become more and more numerous and stronger, and appropriate control applications can be made according to the manifestation of the fault.

5.2 Obvious electronic data automation features emerge

Computer data automation is developing faster and faster, and the modernization of relay protection technology will inevitably be fully reflected, that is, the active performance of electronic data will inevitably be manifested.

5.3 The application of relay protection technology is convenient and flexible

The widespread application of this technology will make the maintenance and commissioning of power lines more convenient. During operation, the operator can make appropriate adjustments based on the current value.

In summary, the main trend is towards computerization, networking, integration of protection, control, measurement, data communication and artificial intelligence.

6 Conclusion

The development of relay protection technology in my country's power system has gone through four stages. With the rapid development of power systems and the advancement of computer technology and communication technology, relay protection technology is facing a trend of further development. Its development will see breakthroughs in principles and applications, and will move from the digital age to the information age, developing to a new level. This puts higher demands on relay protection workers and opens up a broad space for activities.