Voltage transformer disconnection fault handling method - Database & Sql Blog Articles

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

Inductance

A voltage transformer, commonly known as a PT (Potential Transformer), is an electrical device that steps down high voltages from the power system to a lower, safer level for use in measuring instruments, relay protection systems, and automatic control devices. It plays a crucial role in ensuring accurate monitoring and safe operation of electrical systems. The primary winding is connected to the high-voltage side of the circuit, while the secondary winding is connected to the low-voltage side, allowing for safe measurement and control without direct electrical connection. This isolation helps protect sensitive equipment and personnel. PTs are generally very reliable, with few reported failures. In our 20 years of experience, we have not encountered any major incidents such as insulation breakdown, winding damage, or internal short circuits. However, one common issue is the disconnection of the PT circuit, which can lead to incorrect readings and potential operational problems. During our operations, we've experienced this failure twice. Based on our practical experience and industry references, here's how we handle PT circuit disconnections: When a PT circuit breaks, you may observe the following symptoms: the "voltage circuit broken" light is on, an alarm sounds, the voltmeter shows zero or unbalanced three-phase voltages, the active power meter behaves abnormally, and the energy meter stops working. There might also be a ground signal if the high-voltage fuse has blown. Additionally, the monitoring voltmeter could show a lower-than-normal reading, while phase-to-phase voltages remain normal. Possible causes include blown or poorly connected fuses on the high or low voltage sides, poor contact in the secondary circuit, faulty auxiliary switch contacts on the PT isolating switch, or loose or broken connectors in the secondary circuit. If a break occurs, follow these steps: 1. Disable relay protection and automatic devices to prevent false trips. 2. If instrument readings are inaccurate due to a secondary circuit fault, rely on other meters to monitor equipment performance and avoid changing the operating mode. 3. Check the high and low voltage fuses. Replace them if blown. 4. Inspect the secondary circuit for loose connections or poor contact. This knowledge comes from years of hands-on experience. We're always looking for ways to improve safety, efficiency, and reliability. We welcome collaborative discussions to develop better prevention and troubleshooting methods.