With the development of national economy and the continuous improvement of people's living standards, residents' dependence and demand for electricity are also increasing, which provides a lot of space for the development of power grid. In particular, the 10kV distribution network is developing rapidly, which is responsible for the normal power consumption of all walks of life and is closely related to people's daily life. At present, the integrated automation system is widely used in substations, which realizes the unattended operation of substations. The integrated automation system is equivalent to the "eyes" and "hands" of operators. However, due to various reasons, some integrated automation systems have relatively low working reliability, frequent faults, normal operation and even accident trip signals can not be transmitted to the background, which seriously affects the reliability of power supply, reduces the credibility of power supply department, and directly affects the efficiency of power supply. Based on this situation, the author mainly analyzes the causes of frequent faults of 10kV integrated automation system in substation. For different reasons, if appropriate measures are taken, the frequent faults of the integrated automation system will be greatly reduced.

The 10kV integrated automation system of substation mainly realizes the functions of monitoring, measurement, control, protection and data communication for the primary 10kV system. The failure of any part of each functional module will affect the operation reliability of the integrated automation system. Generally, the causes of frequent failures of 10kV integrated automation system mainly include: communication device failure, protection device failure, background system failure, etc., in which communication device failure accounts for more than 80% of the total number of failures.

1. Communication device failure

Data communication can not only complete the information exchange and information sharing between subsystems or functional modules in the integrated automation system, but also complete the communication between substation and control center. If any device in the data communication channel fails, it will cause communication interruption and affect the reliability of the integrated automation system.

1.1 network card failure

The network card is the necessary channel for the protection device to upload and exchange information with other intelligent devices. As an integral 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 large, it is bound to increase the number of failures of the communication device. In view of this situation, the author suggests that enterprises try to adopt mature products from well-known manufacturers with high reputation.

1.2 software program failure

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 stability of the software program used in the integrated automation system is not high (such as program confusion, chip damage, etc.), it will also increase the number of failures of the communication device. The software modification is usually carried out by the manufacturer's after-sales technical support personnel. It is suggested that enterprises try to use the products of manufacturers with high popularity and good after-sales service.

1.3 high induction level of external input

If there is a high induced voltage in the network communication connecting line, it is easy to breakdown the capacitor, diode and other hardware, which directly causes the damage of the communication device plug-in.

Most of the primary and secondary cables in the substation are laid in the same trench. When the primary cable or control cable laid in the same trench trips due to fault or the load changes rapidly, a strong alternating magnetic field will be generated according to Faraday's law of electromagnetic induction. At this time, the induced voltage will be higher. If the measures are improper, it will be easy to break down the hardware. To solve this problem, as long as necessary isolation measures are installed between different devices to effectively shield the induced high level generated by other cables in the same channel.

1.4 communication medium failure

The main causes of communication medium failure are the fine core of network cable, high fracture rate and large shielding grounding contact resistance.

To solve the problem of fine wire core and high fracture rate of network cable, we should first adopt network cable with guaranteed quality; In addition, in the process of on-site construction, the network cable shall be laid with protective tube and protective layer, and the setting out shall be carried out in sections to avoid damage to the wire core caused by excessive force.

For the problem of large shielding grounding contact resistance, as long as the grounding of various cables such as communication network cables is firm and reliable in strict accordance with the countermeasures requirements of the State Grid Corporation of China, meets the requirements of the regulations, and plays a shielding role in the external induced voltage.

Harsh environment

Bad environment (such as high temperature in relay room) will also cause communication device failure. In this regard, as long as the temperature of the relay room is reasonably adjusted (such as adding air conditioning equipment).

2. Fault of microcomputer protection device

The main functions of microcomputer protection device are: in case of primary system failure, automatically, quickly and selectively remove the fault equipment from the system, ensure the normal operation of non fault equipment and minimize the scope of power failure; When the primary system is abnormal, it will automatically, timely and selectively send out alarm information. If the failure of the protection device itself (such as misoperation or refusal to operate) cannot realize the above functions, it will inevitably lead to the expansion of the scope of the accident, resulting in personal casualties, equipment damage and major economic losses. Therefore, the integrated automation system should adopt microcomputer protection device with high reliability.

3. Background system failure

The background system is responsible for data acquisition and processing, operation monitoring and alarm, operation control and other basic functions. If the background fails (such as crash, disconnection, program error, etc.), it will not be able to provide on-site information to the operators. Similarly, the operators cannot control the primary system through the background system. It is suggested that enterprises try to adopt products produced by manufacturers with advanced technology, high reliability and stable performance.

4. Concluding remarks

At present, substation integrated automation system has been widely used in the power grid as a substitute for the secondary system of traditional substation. It carries the functions of monitoring, control, measurement, protection and data communication in the substation. If the integrated automation system breaks down frequently, it will seriously affect the safe and reliable operation of the system, and even cause personal casualties, equipment damage and heavy economic losses. Of course, if we can analyze and find the causes of frequent faults in time, and take certain preventive measures in time (such as maintenance, replacement of equipment, etc.), we can effectively control the probability of faults in the integrated automation system.