Study of Line-used Magnetically Controlled Reactor(MCR) Zhanfeng Deng China Electrical Power Research Institute

Main Topic Why controllable reactor is needed Why controllable reactor is needed Types of controllable reactor Types of controllable reactor Principle of MCR Principle of MCR Functions of MCR Functions of MCR MCR vs. TCR MCR vs. TCR Prospect of application in China Prospect of application in China Simulation Simulation Experimental result of low voltage model Experimental result of low voltage model Demonstration project in Jingzhou Demonstration project in Jingzhou

Why controllable reactor is needed Surplus reactive power of transmission lines causes over-voltage in the line at small load; Surplus reactive power of transmission lines causes over-voltage in the line at small load; Conventional reactor reduced the carrying capacity of lines greatly; Conventional reactor reduced the carrying capacity of lines greatly; Low compensation degree is used, which reduces the efficiency of the over-voltage limiting capacity of reactor; Low compensation degree is used, which reduces the efficiency of the over-voltage limiting capacity of reactor; To solve the conflict between over-voltage limiting and carrying capacity reduce, some kind of reactor with changeable parameters must be made. To solve the conflict between over-voltage limiting and carrying capacity reduce, some kind of reactor with changeable parameters must be made.

Type of controllable reactor Transformer type of controllable reactor Transformer type of controllable reactor

Magnetically controlled reactor Bypass Circuir Breaker Rectifier

Principle of MCR

Functions of MCR Increase carrying capacity of transmission lines Increase carrying capacity of transmission lines Limit power frequency over-voltage Limit power frequency over-voltage Limit switching over-voltage Limit switching over-voltage Stabilize network voltage Stabilize network voltage Inhibit second-arc currency Inhibit second-arc currency Reduce network loss Reduce network loss Reduce maintenance cost of switches of capacitors Reduce maintenance cost of switches of capacitors

MCR vs. TCR MCRTCR Lifetime >20 years About 10 years Over-Load Capacity 50% overload for 20min 100% overload for 20sec 50% overload for 20sec 100%overload for 2sec Over-voltage Capacity 2.3 times rated voltage 1.8 times rated voltage THD3%5.8% Space10 sq. ft / Mvar100 sq.ft / Mvar. Capacity limit No theoretical limit Limit by the capacity of main transformer

MCR vs. TCR MCRTCR Loss 0.05% at no load mode 0.5% at rated load mode 0.1% at no load mode 1% at rated load mode Cost of Equipment $20/kvar for 0.02s response time $10/kvar for 1s response time $20/kvar, response time is 0.02s Cost of installation, operation and maintenance Special personnel Not need Need special personnel to install, operate and maintain

Prospect of application in China 220kV Grid 220kV Grid In xinjiang and neimong province, load in the day and at the night changes greatly in some long-distance transmission line. In xinjiang and neimong province, load in the day and at the night changes greatly in some long-distance transmission line. 330kV Grid 330kV Grid In xibei grid, hydro-power accounts for great ratio and power flow changes greatly and frequently. when water is abundant and less power plants run, the capacity of voltage adjustment is weak. In xibei grid, hydro-power accounts for great ratio and power flow changes greatly and frequently. when water is abundant and less power plants run, the capacity of voltage adjustment is weak.

Prospect of application in China 500kV Grid 500kV Grid In the long-distance transmission lines with heavy load, compact transmission line, and the interconnect line, controllable reactor is needed to stabilize the network voltage, increase the carrying capacity and limit over-voltage. In the long-distance transmission lines with heavy load, compact transmission line, and the interconnect line, controllable reactor is needed to stabilize the network voltage, increase the carrying capacity and limit over-voltage.

Prospect of application in China 1000kV Grid （ Excessively high voltage ） 1000kV Grid （ Excessively high voltage ） Its capacitive power is 4-5 times larger than 500kV lines, controllable reactor is more necessary than other voltage-level lines to limit over- voltage, compensate reactive power to stabilize voltage and protect the line against over-voltage. Its capacitive power is 4-5 times larger than 500kV lines, controllable reactor is more necessary than other voltage-level lines to limit over- voltage, compensate reactive power to stabilize voltage and protect the line against over-voltage.

Simulation Model

V-I Characteristic of MCR AC voltage (p.u.) AC current(p.u.) Ic=25% Ic=50% Ic=100% MCR v-I curve looks very like a constant current source when the control current is constant.

Control Characteristic of MCR Output AC Current (p.u.) Control current(p.u.)

Harmonic Characteristic of MCR The characteristic harmonic is 5 th,7 th, 11 th ; the calculation value of harmonic currents is slightly higher than experiment. I_harm/INorm(100%) THD (100%) IAC (p.u.) 5 th 7 th 3 rd 9 th

Simulation Result at 10% Branch 2current (kA) Phasecurrent (kA) Branch 2current (kA) time(10ms/div)

Simulation Result at 25% Branch 2current (kA) Phasecurrent (kA) Branch 2current (kA) time(10ms/div)

Simulation Result at 50% Branch 2current (kA) Phasecurrent (kA) Branch 2current (kA) time(10ms/div)

Simulation Result at 100% Branch 2current (kA) Phasecurrent (kA) Branch 2current (kA) time(10ms/div)

Dynamic Characteristic of MCR Controlcurrent (kA) Phase Acurrent (rmskA) Phase Acurrent (kA) time(10ms/div) Step from 0 to 100%

Dynamic Charateristic of MCR Controlcurrent (kA) Phase Acurrent(,rmskA) Phase Acurrent (kA) time(10ms/div) Step from 100 to 10%

Recovery Voltage and Second-arc Current Peak-peak second-arc current:2.3A Peak-peak recovery voltage: 69kV Second-arc current (kA) time(0.2s/div) Recovery voltage (kA) time(0.2s/div)

Experiment Result MCR Model

Experiment Result at 50% IA IA1 IA2 Branch 2 current(0.25A/m) Phase current(0.25A/m) Branch 2 current(0.25A/m) time(10ms/div)

Experiment Result at 100% IA IA1 IA2 Branch 2 current(0.25A/m) Phase current(0.25A/m) Branch 2 current(0.25A/m) time(10ms/div)

Demonstration project Simulation results show that network voltage of Jingzhou station can increase by 2.3kV and network loss can decrease by 7.2MW as the conventional reactor is replaced by MCR, the over-voltage limit capacity of them are equal.

Demonstration project 120Mvar/500k V MCR

Parameters of 120Mvar/500kV MCR Rated voltage:550kV Rated voltage:550kV Rated Current:126A Rated Current:126A Norm capacity range: 0.05~1.0Qn Norm capacity range: 0.05~1.0Qn Maximum capacity: 1.6Qn Maximum capacity: 1.6Qn No-load Loss: <0.1% No-load Loss: <0.1% Rated Load Loss:<0.6% Rated Load Loss:<0.6% Noise :<75db Noise :<75db It will be put into operation in March,2007.

Control system

Control System

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