Failure PhenomenonFailure Information and Operational Mode Before FailureAt 17:53:50 on May 16, 2016, the protection devices of two sets on Jingchuan II Line operated successively. Phase B was selected for tripping, and the B - phase of circuit breakers 7522 and 7520 was opened. The protection of circuit breaker 7522 detected a permanent fault on the two - circuit line protection device, with a delay of 0.6s. Subsequently, the ABC three - phase of circuit breaker 7522 tripped. During this proces

1. IntroductionDue to long - term operation, faults and accidents of distribution transformers in rural power grids cannot be completely avoided. These faults and accidents are caused by a multitude of factors, such as external forces like damage and impact, and irresistible natural disasters such as lightning strikes. Meanwhile, in some rural areas, the low - voltage lines are inadequately maintained, frequently resulting in overloading and short - circuits, which cause distribution transformer

Introduction to Fuses of American-style Box TransformersAmerican-style box transformers generally use a combination of plug-in fuses and backup protection fuses in series to provide protection. The protection principle is advanced and reliable, and the operation is simple. The backup protection fuse is an oil-immersed current-limiting fuse, usually installed inside the box transformer. It will operate only when a fault occurs inside the box transformer, and it is used to protect the high-voltage

Fault Causes of Distribution TransformersFaults Caused by Temperature RiseImpact on Metal MaterialsWhen a transformer is in operation, if the current is too large, causing the customer load to exceed the rated capacity of the transformer, the temperature of the transformer will rise, which in turn softens the metal materials and significantly reduces their mechanical strength. Take copper as an example. If it is exposed to a high - temperature environment above 200 °C for a long time, its me

In an SF₆ circuit breaker, the SF₆ gas can decompose into toxic and corrosive gases and water in a high-temperature environment, which can damage the insulating layer. To prevent this situation, while effectively strengthening the protection of electrical components, the insulation level should also be improved. In addition, faults should be analyzed, and corresponding measures should be taken for treatment.1 Case AnalysisA 110 kV switch in a substation was struck by lightning, causing a reclosi

High - voltage SF₆ circuit breakers are three - phase AC 50Hz outdoor high - voltage electrical equipment. They adopt a self - energy arc - extinguishing chamber structure and are equipped with spring operating mechanisms. These circuit breakers feature a simple structure, convenient operation, and high safety and reliability. Therefore, they are widely used for the control and protection of transmission and distribution lines and can also serve as tie - type circuit breakers.The 110kV system of

The GIS (Gas Insulated Switchgear) utilizes SF₆ gas as both the insulating and arc-extinguishing medium. It boasts several advantages, such as a small footprint, high reliability, excellent safety, and convenient maintenance. The SF₆ circuit breaker, being an integral part of the GIS equipment, holds a dominant position in voltage levels of 110 kV and above.This article details a fault that occurred during the power generation and synchronization process of Unit 1 in a certain power plant. Speci

In the substation system, high - voltage circuit breakers are power - interrupting devices, among which SF₆ circuit breakers are the most common. Such circuit breakers use SF₆ gas as the main insulating medium. Based on the action of arc energy, SF₆ compressed gas is formed to instantly extinguish the arc, thus achieving the interruption of rated current and fault current, protecting power - cutting lines and electrical equipment from damage. The system is equipped with a complete operating syst

1 OverviewCircuit breakers can connect and disconnect circuits according to the operating mode under normal conditions. They can also quickly cut off faulty equipment based on secondary protection signals when a fault occurs, or connect the circuit to restore power supply after a transient fault is eliminated. Thus, they have the dual functions of control and protection . Currently, there are more than a hundred substations in the Pingdingshan area. In each substation, circuit breakers are requi

With the rapid development of the power industry and the continuous expansion of the power grid, high-voltage electrical equipment has become increasingly important in the power system. As a key device in the power system, high-voltage SF₆ circuit breakers play a crucial role in cutting off and closing circuits, as well as quickly interrupting fault currents during system failures. Thanks to their high reliability, excellent insulation performance, and arc-extinguishing capabilities, SF₆ circuit