CN100423397C - Method for Compensating Coil for Dropping Induced Voltage and Contact Arc Suppression of Three-phase Voltage Stabilizing Control Device - Google Patents

Abstract

The invention discloses a method for reducing the induced voltage of the compensating coil of a three-phase voltage stabilizing control device and suppressing the arc of a contact, which comprises a plurality of primary winding coils connected in series in each phase of the compensating transformer, a control circuit and a method for controlling the taps of each said coil The control contact is characterized in that it further includes: between the two coils in the middle of the plurality of series-connected primary compensation coils, a step-down contact contact is arranged to divide the plurality of series-connected compensation coils into two sections. At both ends of the plurality of series-connected primary compensation coils, an arc suppression coil is connected in series respectively, and the two ends of the arc suppression coil are controlled by control contacts. The induction voltage of multiple compensation coils connected in series can be reduced below 660V. The contact arc suppressing coils added at both ends of the primary compensation coils of each phase, due to the reverse electromotive force generated by the inductive reactance of the arc suppressing coils, the current flowing through the coils cannot change suddenly, so as to achieve the function of arc suppressing and stabilize the voltage. The control device can operate reliably and has practical value.

Description

Method for Compensating Coil for Dropping Induced Voltage and Contact Arc Suppression of Three-phase Voltage Stabilizing Control Device

technical field

The invention relates to a circuit device for compensating reactive power, in particular to a voltage stabilizing and regulating device for phase voltage and line voltage of a three-phase circuit, a method for compensating coils for reducing induced voltage and contact arc suppression.

Background technique

The voltage fluctuation of the existing power grid often exceeds the national regulations during the peak period and the low peak period, even exceeding ±10%, especially the terminal voltage of the low voltage 380V is particularly unstable. The current voltage regulating and stabilizing devices are mainly servo-type voltage regulating methods, and the servo motor type uses carbon brushes for voltage regulation, and the phenomenon of arcing when the carbon brush replaces the thread end slot is easy to burn out the coil and has a high failure rate. It is not suitable for use in relatively harsh environments, which will reduce the operating performance and service life of electrical equipment, and even cause some equipment with strict voltage requirements to fail to work normally, and will also greatly increase energy consumption. There are reasons such as complex structure, poor reliability and high cost in the current voltage regulation and voltage stabilization technology and products. Therefore, it hinders the wide application of voltage regulating and stabilizing technology.

For this reason, on August 27, 2004, our company provided a "Three-phase Voltage Stabilizer Regulation Device and Control Method" with strong adaptability, low energy consumption, simple structure, good reliability and low cost, and applied for the invention Patent, application number is 200410060781.x, published on March 18, 2005 and entered the substantive examination process.

The invention includes a sampling controller containing a microcomputer, a control circuit and a three-phase compensation transformer, and is characterized in that:

The three-phase compensation transformer has only one winding coil for each phase of the secondary winding, the input ends of each secondary winding coil are respectively connected to the corresponding three-phase power supply, and each output end is connected to the corresponding load; each phase primary winding is provided with more than one A number of winding coils and their taps, each tap is connected to the corresponding phase line and neutral line of the input power supply through the control circuit;

The control circuit includes several contactors, the control coils of each contactor are controlled by the sampling controller, through the corresponding contacts, control the corresponding taps of the primary winding coils of each phase of the three-phase compensation transformer and the input Short circuit between corresponding phase conductors, neutral connections or primary windings of the power supply.

The control method of the three-phase voltage stabilizing regulating device of the invention is:

(1) The sampling controller automatically collects the voltage signal from the output end of the compensation transformer connected to the load. The signal is analyzed and judged by the microcomputer system in the controller. If the voltage at the output end fluctuates beyond the range, the sampling controller sends a corresponding command to the controller circuit;

(2) The command issued by the sampling controller includes making the corresponding contactor in the control circuit pass through the contact, connecting the corresponding coil of the primary winding of the compensation transformer and the corresponding line voltage and/phase voltage of the input three-phase power supply;

(3) The corresponding contactor in the control circuit executes the instructions of the sampling controller, and through the corresponding contacts, the corresponding coils of the primary winding of the compensation transformer use the line voltage and/phase voltage of the input three-phase power supply, from small to large and from large to large At least different forward or reverse voltages are superimposed and compensated in an orderly manner. This compensation is reflected on the secondary winding of the compensation transformer connected in series between the power supply and the load, so that the output voltage approaches the set voltage regulation center. value.

For the phase A compensation circuit, the line voltage and phase voltage can be the line voltage between A-B or A-C of the three-phase power supply A, B, C and neutral line N and the phase voltage between A-N; For the circuit, it can be the line voltage between B-C or B-A of the three-phase power supply A, B, C and N and the phase voltage between B-N; for the C-phase compensation circuit, it can be the three-phase power supply A, B, C And the line voltage between C-A or C-B of N and the phase voltage between C-N.

In the three-phase voltage stabilizing control device and its control method with the above structure, the sampling controller automatically samples the voltage signal from the output, and enters the microcomputer system after filtering, and judges through calculation and analysis that the computer sends out instructions to control several related contactors of the circuit to generate actions according to the instructions. , through the corresponding contact control to connect the lead wires of each corresponding winding coil of the three-phase compensation transformer primary, that is, the connection between the tap and the phase wire or head and tail lead wires of the input three-phase power supply. When the output voltage fluctuates greatly, the compensation transformer enters forward or reverse voltage superposition compensation. The compensation reaction occurs on the secondary winding of the compensation transformer connected in series between the power supply and the load, so that the output voltage approaches the programmed value. Central value of voltage regulation and regulation. Among them, the reason why the circuit power supply of each phase of the primary winding of the compensation transformer is alternately taken from the phase voltage and the line voltage of the input three-phase grid is that under the same power capacity, increasing the working voltage of the circuit can effectively reduce the working current, while The rated working voltage of the universal AC contactor is 380/660 volts, which can effectively reduce the impact of current on the contactor or relay, reduce the failure rate, and reduce the cost. The compensation and adjustment voltage range of each gear is even, and the output can be stably controlled The operating curve of the voltage strictly controls the voltage fluctuation within ±3% or ±2%, which is impossible in the existing technology. Moreover, it has a wide range of voltage regulation, high precision of voltage regulation, good output waveform and low cost. , The device has the characteristics of long life and high reliability, which meets the needs of indoor and outdoor voltage regulation and voltage stabilization power supply, and is suitable for loads that require voltage regulation and loads that need to provide different center values of voltage regulation and regulation according to different periods during operation.

In the practical application of the above-mentioned three-phase voltage stabilizing control device, we found that among multiple series-connected primary compensation winding coils, due to the effect of induction, the induced voltage on the coil at the tail end rises very high. At 660 volts, it exceeds the insulation safety voltage between contactors and coils and components in the device. The insulation safety voltage of general industrial and civil electrical devices is 660 volts. Moreover, in the compensation switching of the corresponding winding coils of the device, there is a phenomenon that the contacts of the contactor are short-circuited between the phases or the phase line and the neutral line due to arcing, which affects the normal operation of the three-phase voltage stabilizing and regulating device. Reliability and practicality. Through practice and research, we have found a way to solve this problem.

Contents of the invention

The object of the present invention is to provide a method for compensating the induced voltage drop of coils by a three-phase voltage stabilizing control device.

Another object of the present invention is to provide a method for arc suppression of a compensation coil contact of a three-phase voltage stabilizing control device.

The invention comprises a plurality of primary compensation winding coils connected in series for each phase of the compensation transformer, a control circuit and control contacts for controlling taps of the coils,

The method of compensating the induced voltage drop of the coil is as follows:

Between the two coils in the middle of the plurality of series-connected primary compensation coils, a step-down contact contact is provided, and the plurality of series-connected compensation coils are divided into front and rear sections. When the rear section/front section is not used, the step-down The contact contact disconnects the rear/front coil to reduce the induced voltage.

The method of compensating coil contact arc suppression is as follows:

At both ends of the plurality of series-connected primary compensation coils, another arc suppression coil is connected in series, and the two ends of the two arc suppression coils are also controlled by the control contacts.

In the middle of the primary compensation coils of each phase of the compensation transformer of the three-phase voltage stabilization control device, a step-down contact contact is set, and multiple series-connected primary compensation coils are divided into two sections in the middle, thereby reducing the induction of multiple series-connected coils The voltage problem reduces the induced voltage to below 660V, satisfies the safe insulation voltage of each component in the circuit, reduces the cost, and increases the reliability of the voltage stabilizing control device. The control contact arc suppression coils added at both ends of the primary compensation coil of each phase, when the control contacts of the arc suppression coil are closed/disconnected, the control contacts of other coils are also closed/disconnected. The inductive reactance produces a reverse electromotive force, so that the current flowing through the coil cannot be mutated, so as to achieve the effect of arc suppression. The voltage stabilizing control device can operate reliably and has practical value.

Description of drawings

Fig. 1 is a schematic diagram of a phase compensation circuit and part of the control circuit in the present invention.

Fig. 2 is a vector diagram of the induced voltage of the primary compensation coil in Fig. 1 .

Detailed ways

Below, the present invention will be described in detail in conjunction with the accompanying drawings.

The present invention is carried out on the basis of the company's previous application "Three-phase voltage stabilizing control device and control method", the application number is 20410060781.x. In order to express clearly, the working principle of the present invention will be described below with the structure and compensation method of the A-phase circuit in the three-phase circuit, and the circuit structures of the other phases are the same.

As shown in Fig. 1, it is a schematic diagram of the compensation circuit of phase A of the present invention, and the structural principles of the other two phases are the same, and so on. In FIG. 1 , the protective contact KD of the original application is omitted for the sake of clarity. The A-phase secondary winding of the three-phase compensation transformer T has a coil Q, one end is connected to the input power supply U _A , and the other end U _{is connected to} the load. The number of turns of the secondary winding coil Q is n. The primary winding has six coils Q1, Q2, Q3, Q4, Q5, and Q6, among which coils Q1, Q2, and Q3 are the first part of the winding, coils Q4, Q5, and Q6 are the second part of the winding, and the coils Q1 and Q6 at both ends are the control coils. Contact arc suppression coil. The turns of the six coils are N1, N2, N3, N4, N5, and N6 respectively. Each coil has lead wires, that is, the primary winding has 8 taps. These 8 taps are normally opened by the corresponding contactors in the control circuit. Points 1K ~ 8K are connected to the A/B/C phase line or neutral line of the input three-phase power supply.

In Figure 1, according to the basic principle of the transformer "the voltage ratio of the primary and secondary windings is equal to the turns ratio of the primary and secondary windings", the working principle of this compensation circuit can be deduced. Assuming that the input voltage of the A-phase secondary winding of the compensation transformer T is U _A , the number of turns of the secondary winding coil Q is n, the compensation voltage generated in the secondary winding Q is ΔU, and the output voltage U _{is output .} When it deviates from the set value, it is controlled by the sampling controller and the control circuit.

When the output voltage _Uout is higher than the set value, there are:

When compensating the negative voltage of the first gear, the contacts 1K, 5K, and 7K are closed, and the compensation voltage obtained in the secondary winding Q of the compensation transformer is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AN</span>}}}{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AN</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}}$

是相线A与零线N之间的相电压。in

is the phase voltage between phase line A and neutral line N.

Similarly, when compensating the negative voltage of the second gear, the contacts 1K, 5K, and 6K are closed, and the compensation voltage obtained in the secondary winding Q of the compensation transformer is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}$

in is the line-to-line voltage of phase AB, which is 30 degrees ahead of the phase angle of the phase voltage of phase A. When compensating the negative voltage of the third gear, the contacts 1K and 4K are closed, and there are:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}$

When compensating the negative voltage of the fourth gear, the contacts 1K and 3K are closed, and there are:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

是AB相的线电压，它比A相的相电压的相位角超前30度。如果电压为A-C线电压则比A相滞后30度。in

is the line-to-line voltage of phase AB, which is 30 degrees ahead of the phase angle of the phase voltage of phase A. If the voltage is AC line voltage, it lags behind phase A by 30 degrees.

When compensating the 0-level voltage, the contacts 1K, 5K, and 8K of the control circuit contactor are closed, and the primary winding coils Q1, Q2, Q3, Q4, Q5, and Q6 of the compensation transformer T are also short-circuited ΔU=0V.

The A-phase output voltage of this compensation circuit Of course, the AB line voltage used in the above analysis can also use the AC line voltage.

When the positive voltage needs to be compensated, the principle and calculation method of the compensation voltage are the same as above, and the closing order of each contact is different.

When the output voltage _Uout is lower than the set value, there are:

When compensating the positive voltage of the first gear: contacts 2K, 5K, 8K are closed;

When compensating the positive voltage of the second gear: contacts 3K, 5K, 8K are closed;

Detailed voltage equation analogy.

In Fig. 1, due to the addition of the arc-extinguishing winding coils Q1 and Q6, the electric flashover caused by the on/off of the control contacts during the switching process of each coil is avoided. A short circuit occurs. At the same time, a contact control contact 5K is set between the two partial windings of the coils Q1~Q3 and Q4~Q6, which effectively avoids the induced overvoltage caused by the serial connection of all winding coils when the compensation voltage is only applied to one partial winding. The phenomenon appears, which can effectively control the induced phase-to-phase voltage below 660V.

The working principle of the step-down contact contact 5K is illustrated below with respect to the circuit in Figure 1:

When compensating the negative voltage of the fourth gear, the contacts 1K and 3K are closed, and the voltage applied to the coil Q1+Q2 is U _AB line voltage, such as 400V, assuming that the step-down contact contact 5K is closed at this time, or no step-down is set The contact contact 5K, that is, the coils Q1~Q6 are all connected in series, then the A-phase induced voltage at the tail end of the coil Q6, which is the upper end of the contact 8K, is

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; AAA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; +</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; +</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; +</span>}{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; )</span>$

When the number of turns of the secondary winding of the transformer is taken as N=1 unit, the number of turns of each primary coil is N ₁ =3, N ₂ =8.75, N ₃ =3.5, N ₄ =7, N ₅ =7, N ₆ =2 ,So,

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; AAA</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 400</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8.75</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8.75</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 3.5</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1064</span>}\mathrm{<span\; class="notranslate">\; V</span>}$

Similarly, U _BB =1064V, U _CC =1064V

In this way, the line voltage induced on the contactor contact 8K is estimated according to the vector diagram in Figure 2, and it is obvious that

U _A'B' = U _B'C' = U _C'A' ≈1510V

It can be seen that the voltage induced on the primary winding at this time is as high as 1510V, which is far greater than the 660V safe insulation voltage of the contactor.

If the step-down contact contact 5K is disconnected, the induced voltage on the coils Q4, Q5, and Q6 is

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; AAA</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; AB</span>}}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 400</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 8.75</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 545</span>}\mathrm{<span\; class="notranslate">\; V</span>}$

Similarly, calculated from the vector diagram in Figure 2:

U _A'B' = U _B'C' = U _C'A' ≈630V

It can be seen that, due to the use of the step-down contact contact 5K to break the connection between the intermediate coil Q3 and Q4, the multiple series-connected compensation coils are divided into two sections, so that in extreme cases, the contact between the contacts of each contactor The induced voltage between phases is below 660V safe insulation voltage. Therefore, when the front or rear compensation coils Q1, Q2, Q3 or Q4, Q5 and Q6 are not used, the front or rear coils are disconnected through the step-down contact contact 5K to reduce the induced voltage.

Of course, in the primary compensation coils Q1~Q6, if the number of turns of each coil is small and the induced voltage of the compensation winding is less than 660V during operation, the step-down contact contact 5K in the middle of the compensation winding can be canceled and shorted, and the circuit works normal.

The working principle of arc extinguishing coils Q1 and Q6 is explained below with respect to the circuit in Figure 2:

Assuming that the original compensation state is to compensate the 0-level voltage, that is, the contacts 1K, 5K, and 8K are closed, and 2K is open; if the positive level 1 voltage needs to be compensated, the compensation state should be changed to the contacts 2K, 5K, and 8K are closed, and the contacts In the process of breaking 1K, electric flashover will inevitably occur. If the coil Q1 is canceled, that is, when N1=0 turns, when the electric flashover generated by contact 1K is relatively large, and before it is completely extinguished, the closing of contact 2K will The 1K electric arc is reignited, and a short-circuit fault between phase A and neutral line N occurs. However, because the present invention has coil Q1, even if the electric flashover of contact 1K is relatively large, and before it is completely extinguished, contact 2K is closed. At this time, because the inductive reactance of coil Q1 produces the effect of reverse electromotive force, the current cannot Suddenly, the electric flashover will not reignite and play the role of arc suppression. Moreover, this arc suppression effect has been proven in practice. Therefore, it effectively solves the problem of short-circuit fault caused by electric arc restrike during the compensation coil switching process of the contactor contact. The setting and working principle of the coil Q6 are the same as those of the coil Q1, and will not be repeated here.

To sum up, the primary compensation windings of each phase of the three-phase compensation transformer T can be provided with a corresponding number of coils and taps to meet the range of voltage regulation and control accuracy, and the contactor of the control circuit can also be provided with multiple contacts as required. The contacts of the contactor, that is, the above-mentioned control contacts, can also use other types of non-contact switching devices, such as switching tubes and thyristor devices. There are also many circuit structures. No matter what scheme is adopted, as long as the switch device switching circuit is connected in series with an arc-extinguishing winding or a contactor (switch) is used to control the on-off control method between two parts of the primary winding, it constitutes a control method for this circuit. Invention infringement.

Claims (1)

1. A method for compensating transformer primary compensating winding coils to drop induced voltage and contact arc extinguishing in a three-phase voltage stabilizing control device, which includes setting multiple series-connected primary compensating winding coils for each phase to the compensating transformer in the device, The control circuit and the control contacts respectively controlling the taps of the coils are characterized in that: The contacts include a step-down contact contact, which is arranged between the two coils in the middle of the plurality of series-connected primary compensation winding coils in each phase, and divides the plurality of series-connected primary compensation winding coils into two sections; Among the plurality of series-connected primary compensation winding coils in each phase, the first coil at the head end and the last coil at the end are arc suppressing coils, the first tap of the first coil at the head end, and the last coil at the end The end taps of one coil are respectively connected to the phase line through corresponding control contacts, and the other end taps of the first coil at the first end and the other end taps of the last coil at the end are respectively connected to zero through corresponding control contacts. line connection.

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