Want to clear up the action of voltaic transformer, what is must understanding next voltaic transformer above all so? Means of mark of voltaic transformer nameplate, note, wiring and the distinction with voltage transformer.

 

 

What is voltaic transformer? It is big electric current by changeover of plan certainty ratio the electric equipment of small electric current, call voltaic transformer. The principle is principle of basis electromagnetism induction, voltaic transformer has the coil of two insulation, cover the core that closes in, . Its winding v/LIT all over the ground number is very few, in the circuitry that strings together the electric current that measures in need, accordingly it often has all electric current of circuit to had flowed, 2 winding v/LIT all over the ground number is more, string receive in be expressed in the measuring instrument and protecting loop.

 

One, mark of voltaic transformer nameplate

 

Voltaic transformer model divides composition by the following, each part letter, symbol shows content:

 

 

The first letter: Transformer of L—— electric current.

 

The 2nd letter: F—— leeway type; M—— generatrix type () of the type that wear core.

 

The 3rd letter: Type of C—— porcelain insulation; Z—— is pouring type.

 

The 4th letter: B—— protection; D—— differential.

 

The first number: Grade of digital —— voltage (KV) .

 

For example LMZ—0.66 expresses to use the 0.66kV of transformer of electric current of the type that wear core with pouring epoxy resin.

 

Rated job voltage: Transformer allows the virtual value of highest and identical voltage that moves for a long time.

 

Rated electric current: Regard transformer function as fiducial electric current value.

 

Rated 2 electric current: Regard transformer function as value of fiducial 2 electric current, it is 5A or 1A normally.

 

Rated electric current compares: Rated electric current and rated of 2 electric current than.

 

Rated bear: Decide the bear of basis of exact form place is worth transformer. Voltaic transformer the bear that 2 the loop impedance beyond terminal of K1, K2 is voltaic transformer. Be in in order to inspect normally power volt-ampere or express with impedance ohm.

 

Rated power factor: Of the part of have rendered great service of impedance of 2 rated bear and rated impedance than.

 

Accuracy grade: In the regulation use condition falls, the bounds that the error of transformer sets in this grade power project is medium in the value metric and commonly used grade has 0.2, 0.5, 0.2S, 0.5S.

 

 

2, note

 

1, deputy edge winding must reliable ground connection, after damaging in order to because be isolated from,prevent, former edge tall voltage is passed into endanger person security.

 

2, answer become absolutely not to allow open a way. The transformer when open circuit was become hold position for nothing, when magnetic flux tower above is rated a lot of (1.4-1.8T) , besides producing transformer of attaint of many iron bad news, still give dangerous maximum pressure in induction of deputy edge winding, endanger person security.

 

3, when voltaic transformer is installed, should consider accuracy class. Precision receives a measuring instrument high to express, precision is used lowly at protection. Should grant to notice when the choice.

 

4, when voltaic transformer is installed, should notice polarity (homonymic end) , the terminal of side is L1, L2 (or P1, P2) , side electric current is flowed into by L1, pour out of by L2. And 2 times the terminal of side is K1, K2 (or S1, S2) namely 2 times the terminal of side is poured out of by K1, flow into by K2. L1 and K1, l2 and K2 are same polarity (homonymic end) , must not make a mistake, be like the sentence that receives kilowatt-hour meter otherwise, kilowatt-hour meter will invert.

 

5, the branch that side winding has voltaic transformer to sheet circles and circle more, LQG circle for sheet and use LMZ model (the type that wear a heart) when should notice to whether there is the data that wear a heart on nameplate, if have,should wear a wants v/LIT all over the ground number by the requirement. Attention: Wearing heart v/LIT all over the ground number is in order to cross hollow medium root number is accurate, is not the computation of v/LIT all over the ground number with periphery (circle the error otherwise) .

 

6, the branch that 2 winding of voltaic transformer have a winding and 2 winding, be like those who have 2 winding, among them a winding is high accuracy (error value is lesser) serve as commonly metric use, another is low precision (error value is greater) use at protection commonly.

 

7, the connection of line of cupreous heart insulation that the link line of voltaic transformer must use 2.5mm2, provisions of some electric industry department must introduce the line of cupreous heart insulation of 4mm2, but plant without this generally speaking necessary (special situation except) .

 

3, the wiring means of voltaic transformer

 

Voltaic transformer basically has the following means of 5 kinds of wiring:

 

(Wiring of form of 1) complete star.

 

(2) two-phase two relay are not complete astral form wiring.

 

(3) two-phase electric current differs one relay wiring.

 

(4) triangle wiring.

 

(5) three-phase is received in order to obtain 0 foreword electric current.

 

4, the distinction of voltage transformer and voltaic transformer on action principle

 

Main distinction is status of the job when moving normally very not identical, expression is:

 

Transformer of 1) electric current 2 can short circuit, but do not get open a way; Voltage transformer 2 can open circuit, but do not get short circuit;

 

2) is opposite for the bear at 2 side, internal resistance of voltage transformer fights lesser down to negligible, can think voltage transformer is source of a voltage; And of voltaic transformer however internal resistance is very great, down to can consider as an internal resistance the current source of infinity.

 

The magnetic flux density when 3) voltage transformer works normally approachs saturation value, density of the magnetic flux when breakdown drops; Density of the magnetic flux when voltaic transformer works normally is very low, and as a result of side short-circuit current becomes very big when short circuit, make magnetic flux density increases greatly, exceed saturation value far even sometimes.

 

5, the polarity of voltaic transformer

 

Voltaic transformer is used in communication loop, the direction of the electric current in communicating loop is in along with time change. What the polarity of voltaic transformer points to is polarity of quarter side when some and 2 side some upright polarity is identical, it is at the same time namely, or it is at the same time negative, call this polarity same polarity end or homonymic end, with symbolic “*” , “-” or ” . With symbolic “*” , “-” or ” .. Express. (also can understand to concern for electric current and 2 voltaic direction) .

 

According to the regulation, mark of head end of voltaic transformer primary coil is L1, tail end mark is L2; 2 times the head end mark of coil is K1, tail end mark is K2. In wiring L1 and K1 call same polarity end, l2 and K2 also are same polarity end. The polarity differentiate of the differentiate that voltaic transformer same polarity carries and coupling coil is identical. Simpler method receives primary coil with 1.5V dry cell for example, with the volts d.c. of one tall internal resistance, many Cheng the watch receives coil 2 times. When switch closes, if discover volmeter hand to deflexion, can decide 1 and 2 it is same polarity end, when switch closes, if discover volmeter finger is retrorse deflexion, can decide 1 and 2 not be same polarity end.

 

6, voltaic transformer moves in the problem that should note

 

(1) voltaic transformer does not get open a way in 2 side in moving, once 2 side open a way, , because iron damage is too big, lukewarm exorbitant and burn down, or make auxiliary winding voltage elevatory and will be isolated from puncture, produce the risk that high pressure gets an electric shock. Changing so when receiving instrument, express like exchange ammeter, have rendered great service, wait for the reentry after answering to answer electric current road weak point to receive first to go without result watch metric appearance exchange. Become after watch plan mix up, it is normal to receive its receive its loop to demolish short wiring to check watch plan again first.

 

If demolishing the discovery when short wiring to have scintilla, right now voltaic transformer already open circuit, should instantly afresh short receive, when finding out metric appearance loop not to have open circuit phenomenon truly, just can demolish short wiring afresh. Undertaking demolishing voltaic transformer short when accepting the job, should stand on insulation skin mat, want to consider the protector of loop of transformer of electric current of out of service additionally, after waiting for the job to end, just can run protector investment.

 

(2) if voltaic transformer has buzz,ring, should check in-house core to whether become loose, can screw core bolt.

 

(3) voltaic transformer the one aspect of the matter of 2 side, crust all wants reliable ground contact.

 

(4) 2 times when voltaic transformer sidetrack encircles insulation resistance under 10——20 million Europe when, must undertake dry processing, after making insulation restores, just can use.

 

7, the action of voltaic transformer

 

The action of voltaic transformer is to make sure economy of power system safety moves, must undertake monitor and be metricaled to the moving circumstance of power facilities. But general measurement and protector cannot receive high-pressured facility directly, and need alternates the big electric current of system in proportion small electric current, supply measures appearance and protector to use.

 

8, the distinction with voltage transformer

 

And the action of voltage transformer is concern tall voltage in proportion the standard that commutation becomes 100V or lower level 2 voltage, use for unit of protection, metric, instrument.

 

Both distinction depends on is to measure electric current one is to measure voltage. Voltaic transformer is series connection is in circuit, winding circles than 2 winding number is little, 2 cannot open circuit; Voltage transformer is paralell connection is in circuit, winding circles than 2 winding number is much, 2 cannot short circuit. Generally speaking, voltage transformer is will tall voltage by certain proportion commutation becomes standard voltage 2 times (100V) equipment. Voltaic transformer is big electric current of will big electric current or high pressure by certain proportion commutation becomes standard electric current 2 times (5A or 1A) equipment.

 

The advantage of commutation:

 

1.Tall depressive electric current, voltage cannot be measured directly, even if has the appearance that can measure the electric current below high pressure, voltage directly, insecure also, the member that it already cited maximum pressure electrical engineering person at the moment, be isolated from namely those who make is again good, unwarrantable also constantly safe.

 

2.When electric current is too big, receive appearance difficulty, what cannot become the wiring post of instrument, appearance is very big.

 

3.After classics transformer alternates, the electric current that already became a standard 2 times (5A or 1A) with voltage (100V) , such no matter 2 appearance, protector, still be electric energy metric appearance, can undertake standardizing, the standardization design that is helpful for appearance, production, choose and safeguard.

 

Summary, after the effect that knows voltaic transformer, voltaic transformer is used at protection of the electric current in power system to reach when measuring, answer to differ according to the polarity of voltaic transformer and scope of application, choose the wiring way of voltaic transformer correctly.