IEC 63042-101-2019 pdf free.UHV AC transmission systems – Part 101: Voltage regulation and insulation design.
ln general, reactive power compensation should be distributed at the primary,secondary andtertiary side of the UHV transformer based on the overall requirements for voltage regulationand to minimize the overall cost.The principle of locating reactive power compensation at theprimary and secondary sides of the UHV transformer is the same except for the cost ofreactive power compensation and its effectiveness in regulating voltage at the primary side ofthe UHV transformer. In this way, they are treated in the same manner.
The major processes in configuring reactive power compensation for UHV AC systems are asfollows:
a) ldentify the range of likely active power flow across the UHV line，then calculate and analyse the characteristics of reactive power and voltage profiles along the UHV line,taking into account charging reactive power produced by UHV lines and reactive powerloss under different power flow conditions. Simulations need to be repeated for eachscenario to determine the compensation that keeps the voltage within acceptable limits.One of the methods for this is to determine the compensation required at each bus byusing a static Var compensator(STATCOM) with a large range.The calculated output ofthe STATCOM that maintains bus voltage at 1,0 p.u. is the required compensation at thatbus.
b) Select UHV transformer tap positions to avoid overvoltage under a range of operating
conditions taking into account UHV substation location，number of transmission linesconnected, and system operation mode.
c) Select capacity and location of UHV line shunt reactors with the following considerations:
1) limiting temporary overvoltage and reducing secondary arc current;
2) balancing charging power of lines and flexibly controlling bus voltage.
d) ldentify total and unit capacity of compensators installed on the tertiary side of the transformer. Total capacity should be selected to reduce the reactive power exchangebetween different voltage levels and maintain bus voltage within the admissible range; theselection of single bank capacity should take into account the maintaining of voltagefluctuations induced by the switching of a single capacitor bank or reactor within areasonable range.Set the dynamic reactive power limits provided by generators within thedesired capability range.IEC 63042-101 pdf download.