33kv Series Static Var Compensator Based On Mcr For Electric Arc Furnace - China

Stabilizing weak systems

Minimizing line loss

Increasing power transfer capability

Providing greater dynamic voltage control

Why choose SVC of MCR Type

High reliability: The SCR is installed in low voltage

circuit, not in main circuit, so, the withstanding voltage

is just 1% of main circuit voltage.

Low harmonic contents: THD is below of 5%, which comply with

related national criterion, if the multiple connections are

adopted, the THD can be reduced below of 1.2%.

Small dimension: the dimension of MCR is about 2/5 of TCR.

It can be able to connect in high voltage power grid, the

cost and floor space are reduced dramatically.

Fast response time(100~300ms), it can fully meet the demand

of dynamic reactive power compensation of power equipments.

No need of cooling devices, which reduce the fault rate,

maintenance cost and floor space.

The advantage of MCR-typed SVC

The MCR-typed SVC was based on traditional saturation

reactor technology; it was put forward by Russia scientists.

They introduced the concept of magnetic valve creatively to

just make the small section of iron core saturation, which

solved the high harmonic problems caused by traditional

saturation reactor, because all iron cores in traditional

saturation reactor are excessive saturation, then result in

nonlinear harmonic.

At the same time, the SVC of MCR type

reduced the dimension, weight and noise of entire system; it

has many advantages, such as: low harmonics, fast response

time, high voltage withstanding level, stable operation,

small floor space and long service life.

Therefore, the SVC

of MCR type is quickly spreading in Russia, Ukraine,

America, India, China and other countries.

It plays a very

important role in improving power quality, decreasing

reactive power loss, stabilizing power grid voltage and

enhancing the reliability of power grid operation.

Because

MCR-typed SVC adopted advanced micro-electronics technology,

it can regulate reactive power demand and compensation on

bus bar accurately:

The inductive reactive current in main circuit can be

adjusted through changing low voltage DC to regulate main

circuit impedance fast and smoothly, meanwhile, through

cooperating with capacitor bank paralleled in bus bar,

reactive power compensation demand can be realized on bus

bar, and dynamic response and improved power factor can

stabilize bus bar voltage.

Choosing reactor parameters properly connected in series

with capacitor bank, the compensation on fundamental wave

can be obtained, and the harmonic also can be filtered.

Because the SVC of MCR is free of frequent switching from

mechanical parts, then it avoids surge and over-voltage

impact caused by MSC, which enhances the reliability and the

service life of the equipment, as well, protects the other

instruments.

The SVC of MCR type fully absorbed advantages and functions

of TCR-typed SVC by comparison; it solved the problems of

smooth regulation which can not be realized by MSC and TSC,

and also overcome some disadvantages of TCR-typed SVC.

Because the reactor is connected to high voltage main

circuit directly in series, it must stand extra high voltage

and ultra high voltage.

At present, the highest voltage of

reactor in our country reach to 1000KV, and the maximum

capacity reach to 320MVar.

The reactor also has over-load

function; it will not generate big damage to system except

heating, while, the thyristors in TCR-typed SVC is connected

to high voltage circuit directly, the over-voltage will

result in faults and break.

So it is very stable for MCR-

typed SVC to operate under the high voltage circuit with

free of maintenance.

Frequently Asked Questions

A.

The SVC of MCR type adopted iron core reactor, while TCR-

typed SVC adopted air-core reactor, if the loss of MCR-typed

SVC is higher than the loss of SVC with TCR typeC

At first appearance, it seems that the loss of MCR-typed SVC

is higher than the loss of SVC with TCR type because of its

iron core, but after respective loss analysis, we found:

Iron loss is lower compared with entire loss of SVC: the

entire loss of SVC is composed of iron loss, line loss

(copper line loss and aluminum line loss) and SCR heating

loss, the iron loss is not over 5% of entire loss; the iron

loss of ordinary transformer includes magnetic hysteresis

loss and eddy current loss, the magnetic hysteresis loss

takes up about 80%, while, the eddy current loss takes up

20%, because the working state of magnetically controlled

saturation reactor drifts off the zero flux point, it avoids

magnetic hysteresis loss, therefore, the iron loss of MCR is

just 30% of ordinary transformer iron loss, in addition,

iron loss is just 20% more of line loss, so, the iron loss

of MCR is very low.

The main loss of SVC are line loss and SCR heating loss, the

line loss of MCR and TCR is as below: First, TCR with air-

core adopted aluminum lines, MCR with iron core adopted

copper lines, the resistance of aluminum is bigger than the

resistance of copper, so the heat of aluminum is also

bigger.

In addition, in terms of line length, we know from

the impedance formula of reactor: that the square of line

length is in inverse proportion to magnetic permeability of

medium under the same voltage and capacity.

The magnetic

permeability of iron core is 2000~8000times of air magnetic

permeability, so the aluminum line of air-core reactor will

be many times of copper line of iron core reactor under the

same capacity (MCR also has a air gap, but it is very small

and just about several centimeters, and most of magnetic

circuits conduct in iron core ).

The longer the aluminum

line is, the more the line loss is, in case the line loss

need to be decreased, the line cross section will be

increased, which will result in more investment, the cost

performance is very lower.

The SCR of TCR is connected in series to high voltage main

circuit and wants high power capacity; it will generate

heavy heating, so the complex and expensive cooling devices

are inevitable, while, the SCR of MCR is working under the

low voltage and small power, it is no need of cooling

devices except that the capacity of MCR-typed SVC is over

50Mvar, air cooling devices are enough.

In conclusion, the loss of MCR-typed SVC is very low and

just about 1/2 of TCR-typed SVC.

B.

The SVC of MCR type adopted saturation reactor with iron

core, does it generate big noiseC

No matter transformer or reactor, they both generate noise,

but the main reason of noise is not because of saturation

(but of course, the higher the magnetic density, the bigger

the noise, but it can be decreased or eliminated by

technique improvement), it depends on manufacturing process.

At present, the transformer technology in China is becoming

more and more advanced; the noise of big transformer is

decreased below 70db, it fully complies with State

Environmental Protection Standards.

We cooperate with the

first-class transformer/reactor manufacturer to control the

reactor noise below 70db.

Application industrial fields

A complete set of SVC system can be used to generate

constantly varied inductive and capacitive reactive power

with fast response time.

So far, SVC system has been

extensively used in electric power system and industrial

field such as:

Rolling mill, Electric arc furnace and ladle furnace,

Electric railway traction substation, Hoists and other heavy

industrial loads, Long distance power transmission, Wind

power plant and Secondary substation (66KV to 110KV) Etc.

Company Contact:

• Posted By: Zhuhai Wanlida Electric Co., Ltd.

• Phone: 867563395623

• Address: Wanlida Relay Protection Industrial Park, No. 1 Te, Zhuhai , China

• Email:

• Website: http://www.zhwld.com/

• Business Description: Incorporated in 1991, Zhuhai Wanlida Electric Co., Ltd. (www.
  
  zhwld.
  
  com)
  
  ('the Company'), is located in Relay Protection Industrial Park, No.
  
  1
  
  Technology Road, Science and Technology Innovation Coast, High tech
  
  Zone, Zhuhai City, coving a land area of approximately 60 thousand
  
  square meters (including Park 1 and Park2).
  
  The Company was listed for
  
  equity financing on November 13, 2007 (equity securities abbreviated as:
  
  Wanlida stock certificates, code: 002180), with a registered capital of
  
  124, 980, 000 Yuan.
  
  The Company keeps on her aggressive 'production,
  
  study, research and application' co operation with the famous academies
  
  such as Tsinghua University, Chinese Academy of Sciences and Central
  
  China University of Science and Technology and carries out relevant
  
  technology innovation.
  
  It is a national high tech enterprise that deals
  
  with specialized development, production and sales of substation
  
  integrated automation systems and Medium voltage variable frequency
  
  drives, Medium voltage magnetically controlled soft starters, Static
  
  synchronous compensator(STATCOM/SVG), Static VAR compensator(SVC),
  
  Active power filter(APF/AHF), Thyristor switched capacitor bank
  
  (TSC/TSF), High voltage direct current light transmission systems etc
  
  power electronic equipments.
  
  In addition, the Company is known as a
  
  famous manufacturer and backbone enterprise of transformer substation
  
  integrated automation and power electronic equipments fields in China,
  
  and it also acts as fresh blood in the field of energy conservation and
  
  emission reduction.
  
  Wanlida passed the ISO9001 quality system certification, ISO14001 Environment Management System Certification and OHSMS18001 Occupation Health &Safety Management System Certification; All products passed the test of sated authoritative inspection bureau.
  
  And it had been rated as 'National High and New Technology Enterprise', 'Enterprise Recommended by State Economic and Trade Commission for Reconstruction of Urban and Rural Electric Grids', 'Key Software Enterprise Covered by National Program', 'Excellent enterprise of China', 'First choice Manufacturer for Electric Framework Protocol Sponsored by CNPC', 'Excellent Enterprise of Guangdong Province', 'Optimum Good faith Enterprise of Guangdong Province', 'Contract honoring Enterprise of Guangdong Province', 'Top 10 Private Enterprises of Zhuhai City', and 'Enterprise with Grade AAA Bank Credit '.
  
  Wanlida has a very strong R&D teamwork which has a population of over 100 with doctor's degree, postgraduate degree and bachelor's degree etc, and all of the products are designed strictly according to IEC standards; Wanlida has modern standard workshops, it brought advanced SMT production lines and wave soldering machines into company from abroad, and built the first class high voltage and big capacity power electronic equipments assembling and test platform, which is able to realize full load test and ensure that all of products have exquisite technics and reliable quality; At present, Wanlida covers all of domestic areas except Hongkong, Macau and Taiwan, and it also sells the products to Southeast Asia, Middle East, South America, Africa etc over 20 countries.
  
  The Company aims to grow into the most dedicated electric automation enterprise in the world, and commits itself to building the aircraft carrier of power electronic energy efficiency products.