1.1 Setting Value Issues. ① Calculation errors in setting value ② Human setting errors ③ Device setting drift, a. Aging and damage of components b. Temperature and humidity c. Setting drift
1.2 Power Supply Issues. ① Inverter regulated power supply problems, a. High ripple factor b. Poor output power or stability ② DC fuse configuration issues ③ Operating plug-in with DC power supply.
1.3 TA Saturation Issues. Relay protection measurement plays a key role in the operation of the secondary system.The line power frequency parameter tester integratesan异频 test power supply, measuring instruments, and mathematical models into one, eliminating the influence of strong interference, ensuring the safety of instruments and equipment, and enabling extremely convenient, fast, and accurate measurement of power frequency parameters of transmission lines. When the system short-circuit current saturates sharply in medium and low voltage systems,relay protection devices may fail to operate becausethe current transformer has been applied to the relay protection device. On-site feeder protection may be difficult to start due to current transformer saturation, leading to accidents. Common digital relays use microcomputer control, with a main working power supply of only about 5V and a data acquisition level range of only about 10V. Current transformer saturation will cause greater harm to digital relays.
1.4 Plug-in Insulation Issues. Microcomputer protection devices have high integration density and tight wiring. After long-term operation, due to electrostatic effects, electrostatic dust may accumulate around the solder joints of plug-in wiring. When external conditions permit, a conductive path may appear between two solder joints, causing device faults or accidents.
1.5 High-frequency Transceiver Issues. In the operation of 220kV line protection, these are transceiver issues. The quality of transceivers produced by various manufacturers varies. Before use, strict review should be conducted. Attention should be paid to checking the signal transmission capability and redundancy of relay protection communication equipment (optical fiber, microwave, carrier), to prevent high-frequency protection transceivers from not working due to communication equipment problems. Reasons for high-frequency protection not working include: damage to transceiver components, gaps in the starting signal of the transceiver, strong interference causing false transmission in the high-frequency channel, incorrect wiring inside the transceiver, transceiver blocking, and misoperation during external faults.
