Abstract: Substation integrated automation system has been widely used in the power grid, bearing the functions of monitoring, control, measurement, protection and data communication in the substation. If the integrated automation system frequently fails, the accident trip signal can not be transmitted to the background, which seriously affects the reliability of power supply, reduces the credibility of the power supply department, and directly affects the power supply efficiency. Of course, if we can timely analyze and find the causes of frequent failures, timely take certain preventive measures (such as maintenance, replacement of equipment, etc.), we can effectively control the probability of the occurrence of integrated automation system failures.
Key words: integrated automation system communication device fault protection device fault background system fault Introduction
With the development of national economy and the continuous improvement of people's living standards, residents' dependence on and demand for electricity is also increasing, which provides a great space for the development of power grid. In particular, 10kV power distribution network develops rapidly, which is responsible for the normal electricity consumption of all walks of life and is closely related to People's Daily life. At present, integrated automation system is widely used in substations to realize unattended substations. Integrated automation system is equivalent to run "eyes" and "hands", but for various reasons, part of the integrated automation system operation reliability is relatively low, frequent malfunction, normal operation and even accidents tripping signal can't spread to the background, the serious influence power supply reliability, reduce the credibility of the power supply departments, and directly affect the power supply efficiency. Based on this situation, the author mainly analyzes the reasons for frequent failures of substation 10kV integrated automation system. For different reasons, if appropriate measures are adopted, the frequent failure of integrated automation system will be greatly reduced.
The substation 10kV integrated automation system mainly realizes the functions of monitoring, measuring, controlling, protecting and data communication for a 10kV system. The failure of any part of each function module will affect the reliability of the integrated automation system. The frequent failures of 10kV integrated automation system are mainly caused by communication device failure, protection device failure and background system failure, among which communication device failure accounts for more than 80% of the total failures.
1. Communication device failure
Data communication can not only complete the information exchange and sharing among subsystems or functional modules in the integrated automation system, but also complete the communication between the substation and the control center. If any device in the data communication channel fails, the communication will be interrupted and the reliability of the integrated automation system will be affected.
1.1 NIC Faults
The network adapter is a necessary channel for information uploading and downlink exchange between the protection device and other intelligent devices. As a part of the current microcomputer protection device, if the production management is not in place, the quality is not high, and the number of failures is more, it is bound to increase the number of failures of communication devices. In view of this situation, the author suggests that enterprises try to use high reputation, well-known manufacturers of mature products.
1.2 Software program Faults
The hardware system of communication device is composed of microcomputer system and its peripheral interface circuit, which is its "skeleton", while the software system is equivalent to its "soul". The realization of data communication function mainly depends on the stable operation of the software system. If the software program used by the integrated automation system is not stable (such as program disorder, chip damage, etc.), it will also increase the number of failures of communication devices. Software modification is usually carried out by the manufacturer's after-sales technical support personnel, and it is recommended that enterprises try to use the products of well-known manufacturers with good after-sales service.
1.3 High external input induction level
If there is a high induced voltage in the network communication connection line, it is easy to break down the capacitor, diode and other hardware, directly causing the communication device plug-in damage.
The primary and secondary cables of substations are mostly laid in the same trench. When the primary cable or control cable laid in the same trench has fault trip or load changes rapidly, according to Faraday's law of electromagnetic induction, strong alternating magnetic field will be generated, and the induced voltage will be higher. If improper measures are taken, it will easily break down the hardware. To solve this problem, it is necessary to install necessary isolation measures between different devices and effectively shield the induction high level generated by other cables in the same ditch.
1.4 Communication media Faults
The fault of communication medium is mainly caused by the high fine fracture rate of the core of the network cable and the high shielded grounding contact resistance.
To solve the problem of high fine fracture rate of network cables, the quality of network cables should be guaranteed first. In addition, in the process of site construction, the network cable should be laid with a protective tube layer, and the wiring should be carried out in sections to avoid artificial damage to the core caused by excessive force.
For the problem of large shielded grounding contact resistance, as long as the state Grid corporation of China's countermeasures in strict accordance with the requirements, communication network cables and other cables solid and reliable grounding in accordance with the requirements of the code, external induction voltage shielding.
1.5 Poor Environment
Poor environment (such as high temperature in relay room) can also cause communication device failure. In this regard, as long as the reasonable adjustment of the temperature of the relay room (such as installation of air conditioning equipment) can be.
2, microcomputer protection device failure
The main function of microcomputer protection device is: when a system fails, it can automatically, quickly and selectively remove the faulty equipment from the system to ensure the normal operation of non-faulty equipment and minimize the scope of power failure. When a system exception occurs, the system automatically generates an alarm in a timely manner. If the protection device itself fails to realize the above functions (such as misoperation or refusal), the scope of the accident will be expanded, resulting in personal injury, equipment damage and major economic loss. Therefore, the microcomputer protection device with high reliability should be used in the integrated automation system.
3. Background system failure
Background for the data acquisition and processing system, the basic function such as operation monitoring and warning, operation control, fault occurs if the background (such as crashing, drops, program error, etc.), that will be a very good will not be able to the scene of the information provided to the operators, operators also can't through the backend system to control a system operation. It is suggested that enterprises try to use products from manufacturers with advanced technology, high reliability and stable performance.
4. Conclusion
At present, substation integrated automation system has been widely used in the power grid as a substitute for the traditional substation secondary system, which carries the functions of monitoring, control, measurement, protection and data communication in the substation. If the integrated automation system frequently fails, it is bound to seriously affect the safety and reliable operation of the system, and even cause personal casualties, equipment damage, and great economic losses. Of course, if we can timely analyze and find the causes of frequent failures, timely take certain preventive measures (such as maintenance, replacement of equipment, etc.), we can effectively control the probability of the occurrence of integrated automation system failures.
