When a large amount of capacitive power passes through the inductive components of the system (generators, transformers and transmission lines), the voltage at the end of the line will rise. This voltage rise caused by distributed capacitance is called "capacitance effect" or "capacitance rise" phenomenon or "Faraday effect" in power engineering. This phenomenon is especially serious when the power system is in light load operation mode. The capacitance effect of the long line with no load will lead to the increase of the terminal voltage of the line, because:

The live line is insulated from the earth, and electrostatic induction can occur between it and the earth to form a capacitor. Similar to a flat capacitor. Theoretically, there is a capacitive effect between any two insulated conductors.

Assume that the terminal voltage at the head end of the line is U 1, U2, XC, XL and R. XL>& gtr, R can be ignored, for long-distance transmission lines, xc >；; The phase difference between the voltage on XL and C and the voltage on L is 180. The power supply voltage US≈UC-UL, and the voltage drop on the capacitor is greater than the power supply voltage, so the terminal voltage U2 > U 1.

In order to weaken the influence of "power frequency voltage rise", shunt reactors are often installed in the middle or end of long-distance transmission lines, and the capacitive charging power on the lines is compensated by the inductive reactive power of the reactors to reduce the power frequency voltage rise.