During the switching of normal load or short-circuit current, SF₆ molecules are ionized and fragmented by the arc. The figure illustrates the main reaction processes and the locations where each process is likely to occur. SF₄, as the primary decomposition product resulting from the electric discharge, first reacts with H₂O on the inner wall surface, giving rise to SOF₂. The metal fluorides remain in the form of powder or dust on the surface. H₂O is released in this reaction and thus becomes ava

For intelligent switchgear, the opening time is defined as the duration starting from the moment when the first message carrying the trip command (a GOOSE message in accordance with the IEC61850 series) is received through the interface, with the circuit - breaker initially in the closed position, and ending at the instant when the arcing contacts of all poles are separated.Regarding the closing time of intelligent switchgear, it refers to the time span from the reception of the first message co

This test serves to ascertain the length and condition of the current - carrying section of the arcing contacts within SF6 circuit breakers. DRM (Dynamic Resistance Measurement) tests are carried out by passing DC current through the breaker's main contacts during the breaker's operation. Subsequently, the breaker analyser computes and plots the resistance as a function of time. When contact movement is concurrently recorded, the resistance at each contact position can be determined. Through DRM

Three Phase WattmeterDefinition: A Three - Phase Wattmeter is an instrument employed for measuring the power in a three - phase circuit. In a three - phase Wattmeter, two individual Wattmeter elements are integrated within a single housing. Their moving coils are positioned on the same spindle.Three - Phase Wattmeter StructureA three - phase wattmeter consists of two elements. Each single element is a combination of a pressure coil and a current coil. In the wattmeter, the current coils are rega

Before Equipment Enters ServiceTo ensure the quality and condition of the gas in the equipment before it is put into service, measurements are typically taken for the SF6 percentage and humidity.Additionally, it is necessary to determine the presence of SF6 decomposition products. Normally, the results should always be below the permitted levels for re - use.During Equipment Service (Based on a Periodic Maintenance Regime)Regularly, measurements are carried out for the SF6 percentage, decomposit

“First trip” testing is crucial for assessing the condition of the coil operating mechanism and providing insights into how the circuit breaker will perform in an actual fault scenario. Thus, capturing the first trip operation is fundamental for effective circuit breaker condition monitoring.A circuit breaker spends the majority of its lifespan conducting current without any operation. Once the protective relay detects an issue, a circuit breaker that may have been idle for a year or even longer

A substation supplies energy to the local area where the power lines are located. Its primary function is to gather the high - voltage energy transmitted from the generating station and then step down the voltage to a suitable level for local distribution. Additionally, it provides facilities for switching operations.There are two main types of substations. One is the simple switching - type substation, which is responsible for establishing different connections between transmission lines. The o

In an electrical system, harmonics refer to the components with frequencies that are integer multiples greater than the fundamental frequency obtained by decomposing a periodic non-sinusoidal alternating quantity through Fourier series, and they are usually called higher harmonics.The main causes of harmonics are as follows: Existence of Nonlinear Loads: This is the primary cause of harmonics generation. For example, power electronic devices, including rectifiers, inverters, and frequency conver

Photo - acoustic infrared detectors operate based on the pressure waves emitted by SF6 molecules when they are illuminated by monochromatic infrared light. Specialized microphones detect the acoustic signal, which is directly proportional to the energy absorbed. Sensitivities as low as 0.01 μl/l can be attained, far surpassing those of other methods. However, the response time of approximately 15 s restricts the use of this device for leak localization.Electron capture detectors utilize a ß - pa

A substation is a crucial component of an electrical supply system. It serves to transmit high - voltage electricity from generating substations to local distribution networks. During the journey from power generation to distribution, the voltage often undergoes changes across multiple substations. Below, the various types of substation layouts are explained in detail.Typical Radial SubstationAs depicted in the figure below, a radial substation has a single power source for supplying the load. T