This part of IEC 60143 covers protective equipment for series capacitor banks, with a size larger than 10 Mvar per phase. Protective equipment is defined as the main circuit apparatus and ancillary equipment, which are part of a series capacitor installation, but which are external to the capacitor part itself. The recommendations for the capacitor part are given in IEC 60143-1:2004. The protective equipment is mentioned in Clause 3 and 10.6 of IEC 60143-1:2004.
The protective equipment, treated in this standard, comprises the following items listed below:
- overvoltage protector,
- protective spark gap,
- bypass switch,
- disconnectors and earthing switches,
- discharge current-limiting and damping equipment,
- voltage transformer,
- current sensors,
- coupling capacitor,
- signal column,
- fibre optical platform links,
- relay protection, control equipment and platform-to-ground communication equipment.
Principles involved in the application and operation of series capacitors are given in Clause 5.
Examples of fault scenarios are given in Clause 5.
Examples of protective schemes utilizing different overvoltage protectors are given in 4.1.
NOTE Most series capacitors are configured with a single module, unless the reactance and current requirements result in a voltage across the bank that is impractical for the supplier to achieve with one module. Normally each module has its own bypass switch but a common bypass switch can be used for more than one module. See 10.2.3 of IEC 60143-1:2004 for additional details.
The object of this standard is:
- to formulate uniform rules regarding performance, testing and rating,
- to illustrate different kinds of overvoltage protectors,
- to provide a guide for installation and operation.