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Learn about capacitor banks — types, construction, testing, and applications in power factor correction and voltage stability improvement.
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
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
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
Capacitor Elements A capacitor element forms the basic building block of a capacitor unit. It has two metal electrodes. A dielectric medium separates these electrodes. Engineers connect multiple elements in series or parallel to form a capacitor unit’s internal circuit. They join several units in series to match the system’s rated voltage. The required MVAR … Read more
Capacitor Element Winding In the winding process, the material is wound using aluminum foil and polypropylene (PP). First, a layer of PP is placed, followed by a layer of aluminum foil. This layering continues step by step until the complete element is formed. Once the winding is complete, the element is tested on the spot … Read more
In substations, we always see some reactors connected in series with the capacitor bank. First, a circuit breaker along with an isolator connects the capacitor bank to the system bay. After the capacitor bank, a reactor comes in series with each branch of every phase of the capacitor. Understanding the Inrush Current Now, the question … Read more
Normally, most of the utilities use double star ungrounded neutral capacitor banks. They connect series and parallel capacitor units to form that double star design. They normally use it in 33KV systems of electrical power substations. Before going to the detail protection scheme of double star ungrounded 3-phase capacitor bank, we may recall the connection … Read more
Type Tests on Capacitor Bank Routine Tests on Capacitor Bank Acceptance Tests on Capacitor Bank The type tests and routine tests are repeated on samples as factory acceptance tests.