Common ways of reactive power compensation - Database & Sql Blog Articles

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Overview

Provisions for increasing power factor for electrical loads

The "Power Supply Business Rules" stipulates that the power factor of high voltage users of 100kVA and above should be above 0.90; the power factor of other power users, as well as large and medium-sized power irrigation and drainage stations should be above 0.85; the power factor of agricultural power is above 0.80. Below, Xiaobian will introduce to you the method of reactive power compensation.

Synchronous Generator

The synchronous generator in a power plant serves both as an active power source and the most fundamental reactive power source. When operating at a power factor below 1, the generator outputs reactive power to the system. The lower the power factor, the more reactive power it must supply, requiring a higher excitation current. However, since the excitation current cannot exceed the rated value, the amount of reactive power the generator can provide is limited. Additionally, when the generator operates below its rated power factor, the active power output is reduced because the stator current cannot exceed the rated value.

Camera

The camera is essentially a generator that can only generate reactive power and cannot supply active power. During overexcitation, it supplies inductive reactive power to the system. In addition to providing reactive power, the camera can also act as a reactive power consumer by drawing reactive power from the system when under-excited. Adjusting the camera’s reactive load is convenient—simply by changing the excitation current. However, the camera is a rotating motor, which requires significant infrastructure investment, complex maintenance, and high costs. It also consumes some power. With advancements in power container technology and increased usage, modern cameras are rarely used today.

Capacitor

Parallel capacitors are commonly used for reactive power compensation. When connected to the system, they draw a 90° capacitive current, similar to the reactive power supplied by generators or cameras. As a static device without moving parts, capacitors are easy to install, require minimal maintenance, produce no noise, and consume very little active power. This makes them an excellent choice for reactive power sources. Capacitor compensation is typically done in parallel with the load, hence the term "shunt capacitor." The capacitive current from the capacitor compensates for the inductive current of the load, reducing the reactive current on the supply side and improving the overall power factor.