Free Expert Guides on Power Systems, Circuit Design & Electrical Troubleshooting

What is Arcing Ground ？Definition: Arcing ground refers to a surge that arises when the neutral is not earthed. This phenomenon occurs in ungrounded three - phase systems due to the flow of capacitive current. Capacitive current is the current that flows between conductors when a voltage is applied. The voltage across the capacitances is called the phase voltage. During a fault, the voltage across the capacitance in the faulted phase drops to zero, while in the other phases, the voltage increase

Lightning impulse voltage (LIWL) tests and switching impulse voltage tests are carried out to assess the dielectric stress resulting from transient over - voltages induced by lightning strikes and switching operations respectively. An impulse voltage generator produces a steep - front voltage waveform, which is then applied to the test object. A measurement system, consisting of a voltage divider and a digital recorder, is used to measure and analyze the test voltages and their waveforms.The fig

Primary ProtectionPrimary protection, also known as main protection, serves as the first - line of defense. It is designed to rapidly and selectively clear faults within the boundaries of the specific circuit section or element it safeguards. Each section of an electrical installation is equipped with primary protection. This protection mechanism is engineered to respond promptly to abnormal conditions, ensuring that the affected area is isolated as quickly as possible to minimize damage and dis

This test just apply to 3 pole operation circuit breakers.As Fig these circuits use a three-phase current source and, generally, two voltage sources. one voltage source provides the TRV for the first pole-to-clear and the other gives the recovery voltage for the second- and third poles-to-clear, in the case where these poles clear simultaneously as in non-effectively earthed systems.This system have following components: A three phase current source (G) Voltage source 1 with current injection pa

Methods of Voltage Control in Power SystemThe voltage within a power system is subject to variation in accordance with load fluctuations. Typically, the voltage is elevated during light - load periods and reduced under heavy - load conditions. To maintain the system voltage within acceptable limits, additional equipment is necessary. This equipment serves to increase the voltage when it is low and decrease it when it is overly high. The following are the methods employed in power systems for vol

What is Creeping in Energy Meter？DefinitionCreeping in an energy meter is a phenomenon where the aluminium disc rotates continuously when only voltage is applied to the pressure coil and no current flows through the current coil. In essence, it is an error causing the energy meter to consume a minute amount of energy even when no load is connected to the meter.Impact and Causes of CreepingCreeping can increase the disc's rotation speed even under light - load conditions, leading to inflated mete

DefinitionAn electrostatic instrument is a device whose operation is based on the principle of attraction or repulsion between electrodes carrying electrical charges. In other words, it is an instrument that utilizes the static electric field to generate the deflecting torque. Electrostatic instruments are employed for measuring both high and low voltages, as well as the power in a given circuit.Working PrincipleThe electrostatic instrument operates on the principle of mechanical interaction bet

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

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

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