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The relay protection automation device provides support for the safe and stable operation of the power system. If the relay protection automation device has the phenomenon of poor product quality, misjudgment of protection function or improper handling of personnel operation, poor maintenance effect, etc., the reliability and protection ability will not reach the expected effect, and even the phenomenon of protection without protection will also have a huge impact on the safe operation of the entire power system. This also highlights the importance and necessity of reliability analysis of relay protection automation devices.

Introduction

With the rapid development of social economy, under the constraint of the goal of "carbon peak and carbon neutrality", it has become a new trend to build a new power system with new energy as the main body. The larger and more complex new power grid puts forward higher requirements and new challenges to the reliability and stability of the power system. In the rapid development of power system for more than ten years, automation technology has been widely used in the field of relay protection, which has improved the reliability of the power grid. As a barrier to the safe operation of the power grid, the reliability of the relay protection automation device is self-evident.

Analysis of Relay Protection Automation Device and Working Principle

The application scenarios of relay protection automation devices include all aspects of power systems such as power generation, power transmission and transformation, and power distribution. Taking power transmission and transformation as an example, the protection objects of relay protection automation devices are mainly high-voltage transmission lines and substations. The protection functions of relay protection automation devices mainly include the following three aspects: first, main transformer protection, protection functions are mainly current protection, voltage protection, backup protection, etc.; The second is line protection, with over-current break protection and reclosing protection as the main protection. The third is bus protection, the protection function is mainly based on two-stage charging protection and over-current protection.

product quality reliability

Improve R & D production process and product quality

Through continuous improvement of R & D and production process to improve product quality, to enhance the reliability of relay protection automation device, to ensure the safe and stable operation of power system. In simple terms, a single relay protection automation device problems will not have a significant impact on the reliability of the power system, but for new energy as the main body of the new power system, the stability of the power system is based on the relay protection automation device, a single relay protection automation device failure should also be avoided. The more complex a single device, the greater the possibility of device failure. Therefore, it is necessary for relay protection device manufacturers to improve the level of research and development, improve the production process, and simplify the relay protection automation device. On the one hand, it can save costs and achieve quality improvement. The effect of increasing efficiency, on the other hand, can reduce its own load, reduce chip pressure, and improve protection function efficiency.

The production process will also have a non-negligible impact on product quality. The production process is mainly reflected in the production process, raw materials, personnel operation, etc. Relay protection automation devices have strict specifications in the production process. According to the relevant characteristics of electronic devices, it is necessary to prepare welding, assembly, testing, and aging production management specifications, improve welding level, strengthen product assembly capabilities, etc., and ensure that products are free from false welding, Missed welding, electrostatic breakdown and other product quality problems caused by improper production. The quality of raw materials directly determines the quality of the final product and affects the life cycle of the product. Taking thyristor as an example, in the experiment of small signal input and large current and large voltage output, the thyristor with poor product quality can not play a long-term amplification effect, resulting in the failure of the experiment. In addition, the training of production personnel should be strengthened to ensure that production personnel can carry out production in strict accordance with production management standards, take anti-static measures, and treat each link of production with a serious and responsible attitude.

Rich detection means, improve product qualification rate

As the last link before leaving the factory, the test of relay protection automation device should be strengthened by means of technical manual, so as to improve the qualified rate of products leaving the factory. The manufacturer of the relay protection device shall ensure the reliability of the software function of the single device before the product leaves the factory by means of automatic detection system, aging room, manual sampling inspection, etc. At the same time, the hardware of a single device is tested regularly, and the EMC test is carried out on a single device from time to time to ensure the reliability of the hardware function of the relay protection automation device. Through the test of software and hardware, the efficiency of protection is improved.

Functional reliability

Technical Innovation of Relay Protection

In the face of the rapid development and progress of science and technology and the increasingly large and complex power system, relay protection automation devices should also be continuously improved and innovated. For example, multiple relay protection automation devices can locate the fault by recording the fault current, the waveform of the fault, etc., and at the same time can avoid false alarms due to the failure to correctly analyze the fault point. In addition, with the advancement of technology, millisecond protection actions can be achieved, and the sampling data is more accurate.

With the emergence and rapid development of smart substations, the power grid has become increasingly complex, and some problems are prone to occur during operation, breaking the "four basic characteristics" of traditional relay protection. The "transformer merging unit" mode prolongs the working time of the entire relay protection unit. At the same time, a single component may cause operational errors and malfunction, which violates the rapid protection independence of relay protection, the connection system configuration file and secondary equipment are affected. Because there is no visual "virtual circuit" assistance, and there is no clear breakpoint for maintenance isolation, it increases the risks related to the protection and maintenance of the substation site. Therefore, it is necessary to solve the contradiction between relay protection time and selection through the technical innovation of relay protection.

Protection Function Validity

The protection function of relay protection automation device is the key to realize the protection of power grid. Taking the current mutation in the real power grid fault as an example, the relay protection automation device needs to sense the current mutation through current sampling, and judge whether the power grid has a fault by comparing the degree of current mutation and the relationship between the current size and the setting value, so as to take the corresponding protection alarm or action to achieve the effect of protecting the power grid. Therefore, product R & D designers should fully consider the actual operation of the power system, according to the characteristics of the power system, reasonable design device protection function protection logic, while reducing code complexity, so that the effectiveness of product protection functions continue to improve. In addition, in the process of setting the setting value of the relay protection automation device, through the program calculation system fault data, etc., it can accurately determine whether the setting value of the relay protection automation device is reasonable and whether the protection function can play a role.

Operational reliability

Staff reliability

On the one hand, the reliability of relay protection automation device is reflected in the quality and function of the product, on the other hand, it is reflected in the professional quality of the operator, including the professional level and comprehensive quality of the operator. Here requires the operator to be able to take a serious and responsible attitude, correctly handle the emergencies encountered in the daily operation process, to ensure that the product can play a normal protection function.

In addition, electric power enterprises should regularly train maintenance personnel, continuously strengthen the improvement of relay protection maintenance skills, and strengthen the work quality of maintenance personnel. It is clear that the relay protection maintenance staff shall inspect one by one in strict accordance with the maintenance process during the maintenance process to prevent fluke psychology and ensure that the relay is not worn, and the relay contacts are not adhered, burned out, stuck, etc. Check whether the position of panel display, indicator light, connecting wire, changeover switch, soft and hard pressure plate of automatic relay protection device is correct. Through training and practical operation training, the maintenance efficiency of relay protection automation device is continuously improved, and its operation effect is strengthened.

Regular maintenance

Regular maintenance is an essential part to ensure the effective operation of relay protection automation devices. Make preparations before regular maintenance, mainly including understanding the wiring of the equipment and the installation of the secondary circuit through the drawings, and understanding the recent operation of the product. In the maintenance process, considering the safety, the relay protection automation device should be set in the maintenance state, and the secondary circuit, the insulation of the secondary circuit, the screen cabinet, the effectiveness of the protection function, etc. should be checked. After all inspections, plug-ins are strictly prohibited. The maintenance process should be carried out in strict accordance with the operation manual to avoid missing items and reduce the possibility of product errors.

Conclusion

With the continuous development of economy and society, the continuous progress of science and technology, the competition in the power industry is more intense, and the requirements are constantly improving. If power companies want to gain a foothold in the highly competitive and demanding power industry, they need to use quality relay protection automation devices and cultivate a group of skilled, capable and responsible employees. Through the reliable quality, reliable function and reliable operation of the relay protection automation device, the safe and stable operation of the power system is guaranteed, and the core competitiveness is maintained in the highly competitive power market.