CN1419134A - Single phase power source measuring method and device for 2 type transformer rate - Google Patents

Abstract

The invention discloses a single-phase power-supply measuring method of Z-transformer transformation ratio and the equipment. On a fixed transformer, the turn-number ratio is fixed, exert testing voltage between two phases of primary winding and then according to the testing voltage relation get the transofrmer transformation ratio to convert out the practical ratio. On Z-transformer, it needs two-time test to get turn-number ratio of primary winding to two secondary ones and according to two votlage phase relation in practical run, calculate the practical ratio.

Description

The single phase poaer supply measuring method and the device of Z type transformer voltage ratio

Technical field

The invention belongs to the transformer testing technology, be specifically related to the method and apparatus of transformer voltage ratio test.

Background technology

The no-load voltage ratio of power transformer and group test are the important contents of power equipment preventive trial, remove conventional Y/Y, the Y/ Δ, Δ/Y, outside the power transformer that Δ/Δ connects, also have a large amount of special transformers in electric system or large industrial enterprise, wherein Z type transformer is very common a kind of mode of connection.Conventional power transformer no-load voltage ratio method of testing generally has two kinds of three-phase supply method and single phase poaer supply methods.Wherein the three-phase supply method mainly is the high-pressure side that is added in transformer with three-phase symmetrical power, test both sides magnitude of voltage, the wiring group and the no-load voltage ratio that obtain transformer according to the size and the phase place of voltage.The three-phase supply method can satisfy the transformer voltage ratio and the group test of the various modes of connection in theory, but because general no-load voltage ratio measuring accuracy is had relatively high expectations, the symmetry of three-phase supply is returned the very big influence of generation to measuring accuracy.The three-phase supply symmetry means that promptly three-phase supply is except that amplitude equates, also must guarantee strict phase relation, and in actual application, the three-phase supply that obtains strict symmetry is very difficult, and therefore this method of testing generally is not used in testing at the scene.The single phase poaer supply method is that the test to three-phase power transformer applies single-phase test voltage mutually, non-test mutually then according to the concrete mode of connection or open circuit or with certain short circuit mutually, measure low-pressure side voltage, carry out a certain proportion of conversion according to the different modes of connection then and obtain actual no-load voltage ratio value.Because the single-phase electricity platen press has only stable requirement to voltage source, realize than being easier to, therefore can reach very high measuring accuracy.But only be applicable to the no-load voltage ratio test of conventional transformer, can't be directly used in the no-load voltage ratio test of special transformer.

Summary of the invention

The objective of the invention is to propose a kind of power transformer no-load voltage ratio method of testing of utilizing the single phase poaer supply method to realize the wiring of Z type, a kind of automatic testing equipment is provided simultaneously, to overcome because the difficulty obtained of symmetrical threephase source and single phase poaer supply can't direct applied problems, and satisfy higher measuring accuracy, realize that simultaneously a table apparatus finishes multiple test.

Theoretical foundation of the present invention is: to a fixing power transformer, once fix with the turn ratio of Secondary Winding, certain two alternate test voltage that apply at a winding, then a winding voltage is distributed according to a certain percentage, and in Secondary Winding, induce proportional voltage respectively, obtain transformer turn ratio by the test voltage relation, thereby convert out actual no-load voltage ratio.Only need once test conventional transformer, then need carry out twice test obtaining once turn ratio to Z type transformer, and calculate actual no-load voltage ratio according to the phase relation of voltage in the actual motion to two windings of secondary.

With this method of the present invention that proposes be: (1) is selected to determine transformer connection mode group, apply the individual event test voltage on a winding of transformer; (2) select to determine a winding test phase of transformer, and test corresponding transformer secondary winding two-phase according to this and respectively once test; (3) utilize two voltage ratios of above-mentioned test, calculate two turn ratios of upper and lower half winding of the corresponding Secondary Winding of transformer winding test phase and phase; (4) accurately calculate the no-load voltage ratio value of the test of winding of transformer and corresponding transformer secondary winding according to above-mentioned test result of calculation.

This method of testing is simple and convenient, the measuring accuracy height.

Propose a kind of proving installation by above-mentioned method of testing inventor, it is made up of following equipment:

(1) one comprises and can calculate above-mentioned mathematical model, the central control processor of transformer connection mode group and control;

(2) input that is connected with central control processor, output unit;

(3) the three-phase testing power supply of controlling by central control processor;

(4) select control circuit, low-pressure side test voltage to select control circuit by the transformer high-voltage side test voltage of central processing unit control multidiameter option switch;

(5) accept transformer high-voltage side test voltage and select control circuit and low-pressure side test voltage to select signal filtering, amplification and the D/A change-over circuit of the output of control circuit signal, signal filtering, amplification and the output of D/A change-over circuit are connected central control processor.

This device has the following advantages:

1, be applicable to the transformer connection group and the no-load voltage ratio of various connected modes, comprise single transformer, the Y/Y of three-phase transformer, the Y/ Δ, Δ/Y, Δ/Δ, Y/Z, the Δ/Z mode of connection along with replenishing of computation model, also can be used for the test of other special transformers;

2, internal configurations three-phase testing power supply solves on-the-spot problem and the reality of obtaining the three-phase supply difficulty

Existing group test function;

3, adopt the single phase poaer supply method to carry out the no-load voltage ratio test, guaranteed higher measuring accuracy.

Description of drawings

Fig. 1 Z type transformer connection synoptic diagram

Fig. 2 Z type transformer phasor graph

Fig. 3 proving installation theory diagram

Fig. 4 test voltage source schematic diagram

Fig. 5 test voltage control circuit principle

Embodiment

As shown in Figure 1, Z type transformer generally has Y/Z and two kinds of modes of connection of Δ/Z, and wherein (a) is Δ/Z-0 wiring schematic diagram, (b) is the wiring schematic diagram of Y/Z-1.In general, the Y/Z mode of connection is the wiring of odd number hour, and Δ/Z mode of connection is the wiring of even number hour.

After winding of transformer applies test voltage, can there be certain voltage at the secondary that does not apply the test voltage phase, therefore can't directly measures, but to a fixing transformer, the turn ratio of each winding is fixed, and supposes that winding is K to the turn ratio of first winding of secondary ₁, be K to the turn ratio of second winding of secondary ₂, when then Δ/Z-0 transformer being applied the test voltage of 2U mutually at A, B, the voltage distribution of each winding and the flow direction promptly have shown in Fig. 1 (a):

Respectively with secondary side voltage u _CaAnd u _BcAs low-pressure side voltage, the AB phase voltage is respectively once tested as high side voltage, and its test voltage ratio is respectively K _mAnd K _n, then:

That is:

What transformer applied in the actual motion is three-phase voltage, so each mutual relation of electric voltage of Δ/Z-0 transformer is shown in Fig. 2 (a), has according to the definition of phase relation and turn ratio:

U wherein _LBe line voltage.

Have according to the cosine law:

According to no-load voltage ratio definition and K _m, K _nWith K ₁, K ₂Relation can obtain AB phase no-load voltage ratio and be: $K_{\mathrm{AB}}=\frac{\sqrt{3}}{2}\frac{K_m{K}_{\mathrm{<figure-callout\; id="2"\; label="n\; K\; m"\; filenames="A0214783200122.png"\; state="\{\{state\}\}">n</figure-callout>}}}{\sqrt{K_m^{}}}$

Δ/Z transformer the value expression that can obtain other test phases and other wiring group equally is identical, just K _m, K _nCorrespondence test different mutually, its corresponding relation as shown in Table 1:

The table one Δ/corresponding relation of Z type transformer testing

The mode of connection	The test phase	?K mCorresponding phase	?K nCorresponding phase
				???Δ/Z-0	????AB	????ca	????bc
????BC	????ab	????ca
			????CA		????bc	????ab
???Δ/Z-2	????AB	????ab					????ca
			????BC	????bc	????ab
	????CA	????ca				????bc
			???Δ/Z-4	????AB	????bc		????ab
????BC	????ca	????bc
				????CA	????ab	????ca
???Δ/Z-6	????AB	????bc					????ca
			????BC	????ca	????ab
	????CA	????ab				????bc
			???Δ/Z-8	????AB	????ca		????ab
????BC	????ab	????bc
				????CA	????bc	????ca
???Δ/Z-10	????AB	????ab					????bc
			????BC	????bc	????ca
	????CA	????ca				????ab

To Y/Z-1 type transformer, apply the 2U test voltage mutually at AB, its voltage distribution relation is chosen ab and is carried out K with bc as secondary voltage mutually shown in Fig. 1 (b) _m, K _nTest, each mutual relation of electric voltage of transformer can obtain following expression formula equally shown in Fig. 2 (b):

$K_{\mathrm{AB}}=\frac{\sqrt{3}}{2}\frac{K_m{K}_{\mathrm{<figure-callout\; id="2"\; label="n\; K\; m"\; filenames="A0214783200122.png"\; state="\{\{state\}\}">n</figure-callout>}}}{\sqrt{K_m^{}}}$

The Y/Z transformer value expression that can obtain other test phases and other wiring group equally is identical, just K _m, K _nCorrespondence test different mutually, its corresponding relation such as table two show:

The corresponding relation of table two Y/Z type transformer testing

The mode of connection	The test phase	?K mCorresponding phase	?K nCorresponding phase
				????Y/Z-1	????AB	????ab	????bc
????BC	????bc	????ca
			????CA		????ca	????ab
????Y/Z-5	????AB	????ca					????ab
			????BC	????ab	????bc
	????CA	????bc				????ca
			????Y/Z-7	????AB	????bc		????ab
????BC	????ca	????bc
				????CA	????ab	????ca
????Y/Z-11	????AB	????ab					????ca
			????BC	????bc	????ab
	????CA	????ca				????bc

The concrete steps of Z type transformer voltage ratio test are as follows: (1) is selected to determine transformer connection mode group, apply the individual event test voltage on a winding of transformer; (2) select a winding of definite transformer to test phase, and test respectively once testing mutually of corresponding transformer secondary winding with the corresponding of table one or table two according to this; (3) utilize above-mentioned second test voltage ratio, calculate two turn ratios of upper and lower half winding of the corresponding Secondary Winding of transformer winding test phase and phase; (4) calculate the no-load voltage ratio value of the test of winding of transformer and corresponding transformer secondary winding accurately according to above-mentioned test result of calculation.

Provide a kind of proving installation according to above-mentioned test design, as shown in Figure 3,1 is the three-phase testing power supply of instrument internal by central control processor control among the figure, 2 are high-pressure side test voltage selection control circuit, 3 are low-pressure side test voltage selection control circuit, 4 for accepting signal filtering, amplification and the D/A change-over circuit that transformer high-voltage side test voltage selects control circuit and low-pressure side test voltage to select the control circuit signal to export, and signal filtering, amplification and the output of D/A change-over circuit are connected central control processor.5 can calculate above-mentioned mathematical model for comprising, transformer connection mode group and control central control processor, 6 is input media, be specially keyboard, 7 is output unit, be specially graphic lcd, 8 is tested transformer, the high-pressure side test voltage selects input end connection transformer connection mode, the group of control circuit to select pilot relay J4, J5, J6 mutually with test, and the low-pressure side test voltage selects input end connection transformer connection mode, the group of control circuit to select pilot relay J1, J2, J3 mutually with test.

As shown in Figure 4, the three-phase testing power supply comprises the digital synthesis signal generator DDS that accepts the central control processor control signal, test voltage amplitude control circuit that is connected and voltage power amplifier.Its principle is: being provided with of three-phase supply mainly is the wiring group test that is used for transformer, because wiring group is the unit stepping for spending with 30, therefore less demanding to its symmetry, as long as basic symmetry just can meet the demands, the single phase poaer supply method is then adopted in the no-load voltage ratio test.The output may command of this voltage source.The frequency and the phase place of central processing unit control figure synthesized signal generator DDS output AC signal, the amplitude control circuit is used to select the output voltage that is input as digital synthesis signal generator DDS or zero input of voltage power amplifier, to satisfy the control of three-phase testing power supply and single-phase test voltage, the voltage power amplifier is mainly finished the amplification of voltage signal, obtains the test voltage that needs.

As shown in Figure 5, test voltage selects control circuit (principle of high and low pressure side is identical) to comprise three three road alternate differential amplifier circuits, and the output of differential amplifier circuit connects multidiameter option switch.By central processing unit control multidiameter option switch, the output required voltage is as test voltage.

The principle of work of this device is:

1, by the menu in Chinese prompting of LCD 7, utilize keyboard 6 to select the transformer connection mode, can be single transformer, the Y/Y of three-phase transformer, Y/ Δ, Δ/Y, Δ/Δ, Y/Z, 7 kinds of modes of connection such as Δ/Z;

2, the output three-phase testing power supply of central processing unit control testing power supply 1,2,3 introduce the AB phase voltage signal respectively, and the phase relation that obtains the high and low pressure side through A/D4 and processor 5 is a wiring group;

3, mutually, the state of processor 5 control J1-J6 is to the state of the control of Y/ Δ transformer J1, J2, J3 according to type, the mode of connection, group and the test of tested transformer, to Δ/Y transformer, control J4, J5, the J6 state makes the non-test phase winding of Δ wiring not be with any voltage; All the other modes of connection, J1-J6 is in open-circuit condition;

4, mutually according to type, the mode of connection and the test of tested transformer, the single-phase testing power supply of output voltage of processor 5 control testing power supplies 1, and select control circuit 2,3 to introduce corresponding test signal according to high and low pressure side test voltage.Z type transformer is then carried out twice test and obtains K according to table one, two corresponding relations control 2,3 _m, K _n

5, the test signal of Yin Ruing converts digital signal to through D/A5, and is calculated, handles and convert according to the mode of connection by processor, obtains the no-load voltage ratio value of tested transformer.The conversion factor of Y/Y, Δ/Δ transformer is 1, and the conversion factor of Y/ Δ transformer is

The conversion factor of Δ/Y transformer is

Y/Z, Δ/Z transformer then calculate according to the formula of as above introducing.

6, the repetition said process is tested mutually up to all and is finished, and send display 7 to show the result.

The present embodiment wiring is simple, only needs 6 terminals of transformer high and low pressure side and the corresponding connection of device, and all the other work are controlled realization automatically by instrument.

Claims (7)

1, the single phase poaer supply measuring method of Z type transformer voltage ratio, its characterization method is: (1) is selected to determine transformer connection mode group, apply the individual event test voltage on a winding of transformer; (2) select to determine a winding test phase of transformer, and test corresponding transformer secondary winding two-phase according to this and respectively once test; (3) the individual event test voltage on winding of transformer of utilizing above-mentioned transformer secondary winding voltage value and applying calculates two turn ratios that winding of transformer is tested upper and lower half winding of the corresponding Secondary Winding of phase and phase; (4) calculate the no-load voltage ratio value of the test of winding of transformer and corresponding transformer secondary winding accurately according to above-mentioned test result of calculation.

2, the single phase poaer supply measuring method of Z type transformer voltage ratio according to claim 1, it is characterized in that it be based on Δ/Z transformer voltage ratio value test, its accurate no-load voltage ratio value computational mathematics model is: $K=\frac{\sqrt{3}}{2}\frac{K_m{K}_n}{\sqrt{K_m^2+K_n^2+K_m{K}_n}}$

Wherein: K is the test of winding of transformer and the no-load voltage ratio value of corresponding transformer secondary winding;

K _mFirst mutually the test voltage ratio for the test of winding of transformer and corresponding transformer secondary winding;

K _nSecond mutually the test voltage ratio for the test of winding of transformer and corresponding transformer secondary winding.

3, the single phase poaer supply measuring method of Z type transformer voltage ratio according to claim 1 is characterized in that it is based on the test of Y/Z type transformer voltage ratio value, and its accurate no-load voltage ratio value computational mathematics model is: $K=\frac{\sqrt{3}}{2}\frac{K_m{K}_n}{\sqrt{K_m^2+K_n^2-K_m{K}_n}}$

Wherein: K is the test of winding of transformer and the no-load voltage ratio value of corresponding transformer secondary winding;

K _mFirst mutually the test voltage ratio for the test of winding of transformer and corresponding transformer secondary winding;

K _nSecond mutually the test voltage ratio for the test of winding of transformer and corresponding transformer secondary winding.

4, a kind of single phase poaer supply measurement mechanism of transformer voltage ratio is characterized in that it is made up of following equipment:

(1) one comprises and can calculate above-mentioned mathematical model, the central control processor of transformer connection mode group and control;

(2) input that is connected with central control processor, output unit;

(3) the three-phase testing power supply of controlling by central control processor;

(4) select control circuit, low-pressure side test voltage to select control circuit by the transformer high-voltage side test voltage of central processing unit control multidiameter option switch;

(5) accept transformer high-voltage side test voltage and select control circuit and low-pressure side test voltage to select signal filtering, amplification and the D/A change-over circuit of the output of control circuit signal, signal filtering, amplification and the output of D/A change-over circuit are connected central control processor.

5, as the single phase poaer supply measurement mechanism of transformer voltage ratio as described in the claim 4, it is characterized in that described three-phase testing power supply comprises the digital synthesis signal generator (DDS) of accepting the central control processor control signal, test voltage amplitude control circuit that is connected and voltage power amplifier constitute.

6, as the single phase poaer supply measurement mechanism of transformer voltage ratio as described in the claim 4, it is characterized in that described test voltage selects control circuit to comprise three three road alternate differential amplifier circuits, the output of differential amplifier circuit connects multidiameter option switch.

7, as the single phase poaer supply measurement mechanism of transformer voltage ratio as described in the claim 4, the input end that it is characterized in that high-pressure side test voltage selection control circuit connects the transformer connection mode, group is selected pilot relay (J4), (J5), (J6) mutually with test, and the low-pressure side test voltage selects input end connection transformer connection mode, the group of control circuit to select pilot relay (J1), (J2), (J3) mutually with test.

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