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Here, in this post, we have discussed the DC Control Circuit of an SF6 Circuit Breaker. Selective DC Supply for High‑Voltage Circuit Breakers A circuit breaker’s control power always uses DC. In high‑voltage installations (132 kV and above), designers often choose a selective DC supply. In this scheme, two separate DC sources, Supply 1 and Supply 2, feed … Read more
A vacuum circuit breaker is a current interruption device that uses vacuum as the arc-extinguishing medium. When the contacts open, the arc is quickly extinguished due to the absence of a proper medium in the vacuum. We commonly refer to a vacuum circuit breaker as a VCB. We’ll cover here how they work, why they’re … Read more
Type Tests of a 33/0.415KV Station Service Transformer There are mainly three standards we follow for testing of a Station Service Transformer. These are IS : 1180 part 3 – 2021, CEA Guideline and CBIP Manual. Type Tests According to IS : 1180 part 3 – 2021 According to the latest version of IS 1180 … Read more
We measure the reactive power in VAR. Obviously, here V stands for volts and A stands for amperes. Whereas, R denotes reactive. A power transmission network deals with much larger reactive power. So, normally, we express the reactive power in MVAR. Obviously, 1 MVAR equals one million VAR. What is reactive power? The reactive power … Read more
The transformer differential protection belongs to the unit protection scheme. A unit protection confines itself within a defined zone. A differential protection scheme compares the vector sum of currents entering and leaving the protected equipment. In other words, it uses Kirchhoff’s current law. Under healthy and external fault conditions, the currents entering and exiting the … Read more
Location of Capacitor Banks It is always desirable to connect a capacitor bank as close as possible to the load. This optimizes the use of the capacitor bank. Whenever we connect a load to the power system, the capacitor associated with that load also becomes connected to the system. The capacitor cancels out the reactive … Read more
Let us have a detailed discussion on the Quality Factor and Dissipation Factor. We also call these two factors the Q factor and the D Factor. What is Quality Factor or Q Factor? The Quality Factor, or Q factor, is the dimensionless parameter that describes the efficiency and sharpness of the reactive components. The reactive … Read more
An LCR meter is an advanced measuring instrument. We use it to measure the inductance (L), capacitance (C), and resistance (R) of a circuit. It helps determine the precise values of capacitances, inductances and resistances. These are the three basic parameters of an electrical or electronics circuit. It can measure the three circuit parameters: inductance … Read more
Requirement of Capacitor Banks Let us first discuss the actual requirement of capacitor bank in the power system. Actually, inductive loads such as transformers, motors, reactors, transmission networks, etc., cause current to lag behind the voltage. This increases the phase angle between current and voltage which in turn reduces the cosine of that angle. The … Read more
Why do we use capacitor banks in the system? Generally, these capacitor banks are connected in 33 kV systems. Normally, in a 33 kV system, we use a double star ungrounded capacitor bank. Before discussing the actual connection configuration of a double star ungrounded capacitor bank, let us recall the benefits of a capacitor bank in a … Read more