High-voltage transmission lines, especially high-voltage cables, are capacitive to the power supply end, so line compensation is often connected in series with inductors (electrically called reactors).
Usually connected in series in EHV lines of 330kV and above, its main function is to increase the system voltage from the point of view of compensating (reducing) reactance, thus reducing power loss and improving the stability of the system.
Extended data:
The reciprocal of the equivalent capacitance of a series capacitor is equal to the sum of the reciprocal of the capacitance of each capacitor: 1/C sum =1/c1+1/C2+...+1/cn. Capacitance can be increased in parallel and decreased in series.
For example, if there is no large capacitor at hand, only small capacitors can be used together. On the contrary, if there is no small capacitor, large capacitors can be connected in series. Series capacitor is also a kind of reactive power compensation equipment, which is usually connected in series in EHV lines of 330kV and above. Its main function is to improve the system voltage from the point of view of compensating (reducing) reactance, thus reducing power loss and improving the stability of the system.
The protection and control scheme of series capacitor bank is designed as a complete system, including measuring transmitter, signal transmission system, man-machine interface installed on the ground and corresponding auxiliary equipment. The design principle of protection and control is to protect the capacitor bank and ensure the high reliability and high availability required for the operation of the system capacitor bank.
There are both series elements and parallel elements in the internal components, but different from the above two connection modes, there are parallel elements in the series and strings in the parallel, which belong to the mixed connection mode. There is no uniform format for this connection, which needs to be determined according to the capacity and protection requirements of a single unit during design.
This kind of capacitor is not suitable for complete sets of lOkV class capacitors. Although the connection mode of the components connected in series first and then in parallel is relatively good, its single unit capacity should not be greater than lOOkvar. Fuseless capacitor has the advantages of simple structure, low loss and low manufacturing cost.
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