Treatment methods for common faults and defects in relay protection devices - News - Global IC Trade Starts Here - megadownload

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As a relay protection personnel, the most common daily dealings are various relay protection devices. An important part of daily work is to maintain the protection device, eliminate the abnormality of the device and fault defects. There are many reasons for relay protection relays. According to the division of responsibilities, the responsibility of the operation and maintenance management department, including poor operation and maintenance, misoperation, wiring errors, incorrect installation and commissioning, principles and software defects; responsibility of the infrastructure department, commissioning Poor quality; unreasonable design of the design department, design errors, and other responsibilities and unexplained reasons. The problems caused by the responsibility of the infrastructure design department can be strengthened by the technical supervision and inspection of the whole process; however, the problems caused by the poor manufacturing of the protection device must be solved by the manufacturer.
This paper discusses the elimination of relay protection devices. By analyzing the following common faults and defects of the protection device, a path to solve the corresponding faults and defects is provided, so that the faults and defects can be eliminated relatively accurately and quickly.
First, introduce the case of the protection device that is handled together. On a certain day, the monitoring center notified the city of 110kV A substation 2 main transformer 10kV side 101 switch three-phase current disturbance, jumping from 0A~2A, the three-phase voltage is shown as 40V, obviously abnormal. After going to the scene, check the main transformer protection 101 switch differential current and backup protection three-phase current are about 1.2A, normal. After using the current clamp meter clamp analog input plug-in terminal connected to the measuring current wire, the three-phase measuring current is also about 1.2A, which can eliminate CT fault. After measuring the terminal block with a multimeter, the measured voltage is about 60V, and the PT fault is eliminated. The initial judgment is that the measurement and control device is faulty. After that, contact the manufacturer to replace the analog input plug-in (the current loop is shorted when replacing, do not open the circuit), and the fault phenomenon is not eliminated. It is judged that the CPU plug-in problem, after replacing the CPU plug-in, the fault phenomenon disappears and the device returns to normal. Usually, some of the exceptions are long running times that can easily cause malfunction of the protection device. At present, it is widely used in the abnormality of the microcomputer protection device. In order to facilitate the on-site maintenance personnel, it is not necessary to know the damage of the specific original, as long as the plug is damaged. This is to improve the defect rate of on-site processing. The purpose of the two is that the microcomputer protection hardware is more complicated, the specific faulty components are determined to have higher technical requirements for personnel, and the lack of testing and maintenance equipment. According to my experience, the protection device , a central processor plug-in caused by a power plug or an abnormality. Therefore, just quit the protective device and replace the power plug or plug-in to return to normal. Please note that if you replace the processor plug-in, you will have to set the value and band switch to do the entire set of drive tests before you can start production. Channel loop failure When the device channel fails, the fiber protection channel fault protection device may cause a fault. Therefore, when the device channel alarms, it must be protected from the operation and the maintenance personnel immediately go to the site. Failures are often caused by inexperienced maintenance personnel or effective testing methods, which can be undetected or solved, resulting in fiber protection and timely return to normal operation, thus affecting safe and reliable operation. Fiber protection channel alarms are caused by a variety of reasons. Such as fiber core break, jumper joint loose, pigtail bending is too large or joint fouling, poor fuse quality, multiplex interface equipment failure. Channel defect processing involves the relay protection and communication profession, often involving two substations and units, making processing more difficult. For example, the fiber current differential protection, I believe that the processing channel fault defects should follow the following sequence: check the background information of the equipment and monitoring and whether the transmission and reception status of the protection device is normal; understand the failed Fibre Channel dedicated Fibre Channel or multiple 200 channels. If the multi-channel is channeled, check through the network management system to judge the problem on one side or both sides; use optical fiber test tools, such as optical power meter to test the power of the optical transceiver is normal, the transmission power of different protection devices and The receiving sensitivity is different, please refer to the relevant specifications. During the test, the fiber connector should be inspected for contamination and contact is safe. The core of the special fiber, the protection device test the transmission and reception power, can also be self-loop test to determine the problem. The control circuit open circuit protection device is a common defect to find out the cause of the disconnection of the control circuit, and requires a professional circuit breaker control circuit to understand clearly. According to my actual situation, the reasons for the disconnection of the control circuit are as follows: 1) the wiring is loose; 2) the mechanical blocking relay of the circuit breaker is damaged or other locking contacts are not closed; 3) the auxiliary contact of the circuit breaker is abnormal; 4) the operating box The position relay is damaged. When the control circuit is broken, follow the steps below: 1) In the operation box normally closed contact or TWJ light bright light, as described in the control loop intact, may be twj relay normally closed contact or provide electrical signals, but does not rule out return Signal problem; 2) If the light is not lit, then use the multimeter DC voltage protection screen playback terminal set in the measurement trip circuit to ground voltage is 110V, normal, then the trip circuit from the terminal mechanism box is intact, clear the internal wiring looseness of the device, then The operating box of the problem. Replace the plug; 3) If using a multimeter to measure the voltage of the trip circuit to ground on the terminal block is 110V, then the terminal mechanism box trips the circuit. According to the control loop diagram, the left-to-right terminal or contact measures the voltage to ground, when the voltage is 110V, then the problem is preceded by a cycle between positive and negative potentials. DC grounding is one of the most common defects. It should be found in time to find DC grounding and eliminate it as soon as possible. The steps that can be taken to treat DC grounding are: according to the operating mode, the operating conditions and the impact of climate impact may be ground, using a search method. The method of segmentation processing in the first part, the signal after the first part of the surgery, the principle of the outdoor part, the interior 2 parts. It is a push-pull emergency lighting and anti-misoperation device circuit, outdoor, indoor closed circuit closed circuit, signal circuit and system control circuit, control circuit and main control circuit, DC rectification device and battery circuit. When the DC circuit is cut off, the cut-off time must not exceed 3 s. If the ground is when someone is working and the maximum likelihood of working equipment, you should disconnect the DC power of the equipment, check the DC ground signal loss, such as loss should be found out according to working conditions and location, if not continue to pull the way found. When the ground is wet, the ground should be outdoors exposed to moisture or junction boxes, and then apply a pull search method should be the first to disconnect the relevant switching power supply, power supply, power supply and signal main transformer running power, Instead of disconnecting the power supply protection device of the indoor control circuit, the speed of the ground loop is improved.

The above is my reflection and summary of some common relay protection device faults and defects since I was engaged in relay protection work, in order to help secondary maintenance personnel and construction technicians to quickly and effectively handle field faults and defects. . Of course, limited to a limited level, please correct me. At present, with the construction of the smart grid of State Grid Corporation, the digital and intelligent substation is gradually put into use, and the development of relay protection technology is also advancing with the times. As a technician in relay protection, it is imperative to learn new theories, new technologies and new methods.