Magnetically Controllable Reactor

（MCR）

1.   Summary

MCR is areactor whose reactance value or capacitance can be controlled and adjusted.

2.   New Type Controllable Reactor

Both the new type controllable reactor and traditional saturationreactor originate from the principle of magnetic saturation, but the designphilosophy and way of structure are different, so the working performances ofthem have obviously differences.

In the working process of traditional saturation controllablereactor, the iron core is in a state of magnetic saturation in a long term. Itslosses and current inertia to control winding are big, and the response time islong, therefore, it’s hard to fit for the requirement of the development ofpower grid system.

The new type controllable reactor was endowed with new theory ondesign. It adopts advanced conducting magnetic material and control technology,and overcomes the shortcomings of saturation controllable reactor. It has theability of auto smoothly adjusting self capacity with the changes oftransmission power of HV transmission line. The response time can be designedaccording to different system in 5ms~300ms, and its degree of automation ishigh. Because of its simple structure, the reliability is improved. Meanwhile,it not only reduces the volume, but also reduces the losses and costs. Thesuccess of research and production of the new type controllable reactor fillsin the blank of controllable reactor of our country.

3.   Application of  New Type Controllable Reactor

1. DynamicReactive Compensation of Transmission and Distribution System

Controllable Reactor

Detection and Control System

Figure 1 Diagram of Reactive Compensationof Controllable Reactor

Parallel the fixed capacitor and new typecontrollable reactor to transmission and distribution line, relying on thecharacteristic of adjustable self capacity, which belongs to the reactor, toautomatically balance no-load. The process is reactive compensation (such asFigure 1). The compensation process is: when the line transmits natural power,its reactance value maximizes, capacity minimizes, and the capacitive no-loadtaken in is also minimum. When the transmission power of line is very low, itsreactance value minimizes, the capacity reaches rated value, and it means thecapacitive no-load taken in maximizes. The new type controllable reactor hasthe characteristics of real time detection and quick response, so it can changeits own reactance value instantaneously to attain the aim of balancing no-loadfast and automatically.

The essence of new type controllable reactor is a special parallelreactor, and it can be paralleled to the HV or EHV transmission line directlytogether with the capacitor. Controllable reactor adopts LV DC control, and itis more suitable for HV operation than existing SVC compensation equipment. Thestructure of this kind of reactive compensation is simple, safe and economic,and it is ideal alternative products of reactive compensation of transmissionand distribution system.

At present, the voltage class which was researched and produced byour company and domestic some well-known university is 10kV～110kV, and the maximum capacity is 300Mvar. The response time canbe set between 5ms and 300ms, and the control accuracy of power factor can besteadily controlled from 0.95 to 0.96.

2. Reactive Compensation of Metallurgy Industry

3. Reactive Compensation of Electrified Railway

4. Reactive Compensation of City Secondary Substation

5. Remote Power Transmission Compensation

6. Heavy load compensation of Mining, Communication andOther Enterprises

Miningengine, high power crusher, air compressor, oil pump jack and high powerinverse power supply used in communication service all consume a large numberof reactive electric energy and bring about grid voltage reducing and voltagefluctuation so that the power factor reduces and transmission device producesharmful higher harmonic waves. For power grid, all kinds of enterprises exist alarge number of reactive loads. These loads are the main parts of power gridload. To solve the problems above is to install compensation system nearsubstation of enterprise besides concentrated figuring reactive compensationsystem in transmission and distribution system. It is the most extensiveapplication space to controllable reactor dynamic compensation system.

7. Other Applications of Controllable Reactor

a. Voltage Adjustment and System Protection

Controllable reactor can efficiently restrict power frequencyovervoltage and operation overvoltage.

When the power grid operates normally, the capacity ofcontrollable reactor can make auto smooth adjustment according to the powertransmitted by lines so as to reach the level of steadying voltage. When theline transmit high power, if the condition of the end of three-phase trippingand load rejection turns up, the controllable reactor approaching no-load statecan fast adjust the capacity of reactor to a desired value by fast excitationsystem in order to restrict power frequency overvoltage.

Becauseof the compensation function of controllable reactor, the power frequencyvoltage of no-load line can be restrained so that the level of operationovervoltage of system is reduced, and the level of overvoltage is not more than1.6 times.
The controllable reactor can restrainthe potential supply current. It can largely reduce the potential supplycurrent when the line single-phase grounds matching with neutral-point smallreactance and some control way and it can cause the electric arc extinguishefficiently.

Controllablereactor can also efficiently remove the self excitation of generator. It isharmful for generator to produce self excitation when if operates with no-loadlines. The function of auto smooth compensation of controllable reactor canefficiently remove the condition and phenomenon of producing self excitation.

b. Save Electric Energy
The controllable reactor has the capacity of auto balancing system reactivepower, so it largely reduces reactive losses of system and improves powerfactor of system. It is the important equipment of energy saving and resumptionreducing.

4.  Production Level of New Type Controllable Reactor of Our Company

At present, the voltage class researched and produced by ourcompany and Wuhan university is 10kV～110kV, and the maximum capacity is 300Mvar. We can also speciallydesign products according to parameter provided by users and offer controllablereactor of good performance. We’d like to devote ourselves to electric energysaving project with users, serving domestic power market with advancedtechnology and good production service, contributing to energy saving,consumption reduce and safe production of each industry and mining enterpriseand power department.