Voltage compensation

In a power system, voltage at various buses tends to increase or decrease during its daily operation. To ensure constant voltage to consumers, various techniques are utilized.

When the voltage is below the required level, reactive power produced by inductance needs to be offset by capacitance.

• Synchronous condensers—can be used to generate reactive power, when they are operated as a motor.
• Shunt capacitance —Capacitor banks can be connected in parallel to the transmission lines.
• Series capacitance —Capacitors connected in series, especially for long lines can be used to raise the voltage.
• Tap changing transformers—Transformer tappings can be automatically changed, to alter the voltage accordingly.

When the voltage is above the required level, reactive power produced by capacitance needs to be offset by inductance.

• Shunt reactors—Inductor banks can be connected in parallel to the transmission lines also known as reactors.
• Static VAR compensators—
• Tap Changing Transformers—Transformer tappings can be automatically changed, to alter the voltage accordingly.