CN103941212A - Method for capacitor voltage transformer polarity on-site calibration - Google Patents

Abstract

The invention relates to the technical field of high-voltage power equipment detection, in particular to a method for on-site verification of the polarity of a capacitive voltage transformer. The invention includes substituting a megohmmeter for a DC power supply, and using a megohmmeter, a pointer multimeter, and an insulating pull rod to realize the polarity judgment of the capacitive voltage transformer; wherein: the capacitive voltage transformer is connected to the pointer respectively multimeter and megohmmeter. The present invention replaces the DC power supply with a megohmmeter, makes full use of the existing test equipment on the basis of not increasing additional costs, eliminates the harm caused by the instability of the DC power supply to the equipment, and avoids the problem that the test progress is affected by the insufficient power of the DC power supply. Better serve on-site production, improve work efficiency, reduce test time and cost, realize accurate, convenient and fast judgment of the secondary polarity of capacitor voltage transformer at the substation site, and ensure the safe and stable operation of the substation.

Description

A method for on-site verification of the polarity of a capacitive voltage transformer

technical field

The invention relates to the technical field of high-voltage power equipment detection, in particular to a method for on-site verification of the polarity of a capacitive voltage transformer.

Background technique

The capacitive voltage transformer is developed on the basis of the capacitor bushing voltage extraction device. The voltage conversion is realized through the principle of capacitive voltage division. It has good insulation performance, high withstand voltage level, and is not easy to resonate with the breaker fracture capacitance. It has many advantages such as low cost and can also be used as high-frequency communication, and is widely used in power transmission and transformation systems with voltage levels of 110kV and above. The main function is to be used as a voltage signal sampling device for voltage measurement and relay protection, and to isolate the voltage and current of the primary and secondary circuits in the secondary circuit of relay protection. The secondary voltage signal is an important signal for power system failures. criterion. It should be noted that the transformer has two or more lead-out terminals on the primary and secondary sides. If the polarity of the lead-out terminals is wrongly connected, the phase of the secondary side will change by 180°, which will not only affect the correct operation of the relay protection device, but also affect The operation monitoring and accident handling of the power system will endanger equipment and personal safety in severe cases. Therefore, it is a very important task to correctly judge the polarity of the voltage transformer and the current transformer.

At present, the commonly used method for on-site verification of capacitor voltage transformers is the direct current method, which requires dry batteries as the pressurizing element. When detecting the polarity, connect the positive pole of the battery and the switch to one end of the primary coil in series, and connect the positive pole of the magnetoelectric meter to the same-named end of the secondary coil, and judge the polarity by the deflection of the pointer when the switch is closed. This method needs to prepare a DC power supply and a switch, and the operation is relatively complicated, and the power requirement of the DC power supply is relatively high, which may easily cause equipment damage.

Contents of the invention

In order to overcome the defects of the existing technology, the present invention provides a method for on-site verification of the polarity of a capacitive voltage transformer. Accurately judge the secondary polarity of the capacitor voltage transformer to avoid wiring errors and relay protection failures.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A method for on-site verification of the polarity of a capacitive voltage transformer, comprising: substituting a megohmmeter for a DC power supply, and using a megohmmeter, a pointer multimeter, and an insulating pull rod to realize the verification of the capacitive voltage transformer Polarity judgment; where: the capacitive voltage transformer is connected to the pointer multimeter and the megohmmeter respectively;

The method steps are as follows:

Use the insulating pull rod to click the E terminal of the megohmmeter on the central flange P point of the capacitive voltage transformer, and observe the pointer deflection of the pointer multimeter to judge the polarity of the capacitive voltage transformer;

If the pointer of the pointer multimeter is pointing straight, it is the same polarity, otherwise it is the opposite polarity.

The steps of the described method are as follows:

(1) Open the terminal box of the capacitive voltage transformer, disconnect the external connection wires of the first main and secondary winding 1a\1n of phase A, the second main and secondary winding 2a\2n, and the remaining winding da\dn three coils, and the same Disconnect the first main secondary winding 1a\1n of phase B, the second main secondary winding 2a\2n, and the remaining winding da\dn. External connection wires for the second main secondary winding 2a\2n, the remaining winding da\dn three-coil coils;

(2) Switch the pointer multimeter to a smaller milliamp or millivolt range;

(3) Connect the positive pole (+) of the pointer multimeter to 1a, and the negative pole (-) to 1n;

(4) Ground the L terminal of the megohmmeter line, and connect the ground terminal E to the top of the insulating rod;

(5) The tester holds the insulating pull rod and aligns it with the central flange P point of the capacitive voltage transformer, and the other tester shakes the megohmmeter. When it is fully charged, the tester holds the insulating pull rod and points it at the capacitive voltage transformer. Click on point P of the central flange;

(6) Observe the pointer multimeter personnel to observe. The pointer of the pointer multimeter points to the same polarity, and vice versa.

Advantage of the present invention and application effect are:

It can be seen from the embodiment of the present invention that by replacing the DC power supply with a megohmmeter, the existing test equipment can be fully utilized on the basis of not increasing additional costs, eliminating the damage caused by the instability of the DC power supply to the equipment, and avoiding the damage caused by the DC power supply. The problem of insufficient power affecting the test progress can better serve the on-site production, improve work efficiency, reduce the time and cost of the test, and realize accurate, convenient and fast judgment of the secondary polarity of the capacitor voltage transformer at the substation site. Ensure the safe and stable operation of substations.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Figure 1 is a schematic wiring diagram of a capacitive voltage transformer;

Fig. 2 is a wiring diagram of the present invention.

In the figure: high-voltage capacitor C ₁ , high-voltage capacitor C ₂ , intermediate transformer T, compensation reactor L, damper ZD, protection device F, first primary and secondary winding 1a\1n, second primary and secondary winding 2a\2n, Remaining winding da\dn, carrier device NX, capacitive voltage transformer 1, pointer multimeter 2, megger 3, insulating rod 4.

Detailed ways

The method is to replace the DC power supply with a megohmmeter. When the megohmmeter is fully charged, use the insulating rod to click the E terminal of the megohmmeter on the central flange of the voltage transformer, and observe the direction of the pointer of the multimeter to judge the polarity of the capacitive voltage transformer.

The present invention is a method for on-site verification of the polarity of a capacitive voltage transformer. The DC power supply is replaced by a megohmmeter. The multimeter 2 and the insulating rod 4 realize the polarity judgment of the capacitive voltage transformer 1; wherein: the capacitive voltage transformer 1 is connected with the pointer multimeter 2 and the megohmmeter 3 respectively. Use the insulating pull rod 4 to click the E terminal of the megohmmeter 3 on the central flange P point of the capacitive voltage transformer 1, and observe the pointer deviation of the pointer multimeter 2 to judge the polarity of the capacitor voltage transformer. If the pointer of the pointer multimeter 2 is pointing For the same polarity, otherwise for the opposite polarity. .

As shown in Figure 1 and Figure 2, taking the polarity judgment of a 220kV capacitive voltage transformer as an example, the test site uses common tools for test and maintenance, including ma\mv range pointer multimeter, insulating pull rod, 2500MΩ range megohmmeter, measurement When using the wire, the specific steps are as follows:

1) Open the terminal box of the field capacitive voltage transformer 1, disconnect the external connection wires of the first main secondary winding 1a\1n, the second main secondary winding 2a\2n, and the remaining winding da\dn of phase A, Also disconnect the first main and secondary winding 1a\1n of phase B, the second main and secondary winding 2a\2n, and the remaining winding da\dn, the external connection wires of the three coils, and disconnect the first main and secondary winding 1a\1n of phase C , The second main secondary winding 2a\2n, the remaining winding da\dn three coil external connection wires.

2) Switch the 2nd position of the pointer multimeter to a smaller milliamp or millivolt range.

3) Connect the positive pole (+) of pointer multimeter 2 to 1a, and the negative pole (-) to 1n.

4) Connect the L terminal of the megohmmeter 3 line to the ground, and connect the ground terminal E to the top of the insulating rod 4.

5) The tester holds the insulating pull rod 4 and aligns it with the central flange P point of the capacitive voltage transformer 1 to prepare. Another tester shakes the megohmmeter 3. Point P on the central flange of voltage transformer 1 is tapped.

6) Observe the pointer multimeter 2 personnel to observe, the pointer of the pointer multimeter 2 points to the same polarity, and vice versa.

The specific implementation described above is a preferred embodiment of the present invention, and cannot limit the present invention. The specific implementation manner can be determined according to the technical solution of the present invention and the actual situation. Any other deviating from the technical solution of the present invention Changes or other equivalent replacement methods are all included in the protection scope of the present invention.

Claims (2)

1. a method for capacitance type potential transformer polarity field-checking, is characterized in that:

Comprise: substitute direct supply with megohmmeter, utilize the on-the-spot conventional Work tool megohmmeter (3) of checking experiment, pointer multimeter (2), insulated tension pole (4) to realize the polarity judgement to capacitance type potential transformer (1); Wherein: capacitance type potential transformer (1) is concatenation pointer formula multimeter (2) and megohmmeter (3) respectively;

Method step is as follows:

Utilize insulated tension pole (4) that the E end points of megohmmeter (3) is hit to capacitance type potential transformer (1) center flange P point, observe pointer multimeter (2) pointer and be partial to judge capacitance type potential transformer polarity;

If pointer multimeter (2) pointer just refers to, is same polarity, otherwise is reversed polarity.

2. the method for a kind of capacitance type potential transformer polarity field-checking according to claim 1, is characterized in that: described method step is as follows:

(1) open the terminal box of capacitance type potential transformer (1), disconnect A mutually the first main Secondary Winding 1a 1n, the second main Secondary Winding 2a 2n, residue winding da the external connecting line of dn tri-spiral circle, same disconnect B mutually the first main Secondary Winding 1a 1n, the second main Secondary Winding 2a 2n, residue winding da the external connecting line of dn tri-spiral circle, disconnect C mutually the first main Secondary Winding 1a 1n, the second main Secondary Winding 2a 2n, residue winding da the external connecting line of dn tri-spiral circle;

(2) pointer multimeter (2) gear is switched to less milliampere or millvolt range;

(3) pointer multimeter (2) anodal (+) is connected to 1a, negative pole (-) is connected to 1n;

(4) by megohmmeter (3) circuit L end ground connection, earth terminal E is connected to insulated tension pole (4) top;

(5) it is ready that the test hand-held insulated tension pole of people (4) is aimed at capacitance type potential transformer (1) center flange P point, another test people shakes megohmmeter (3), to be charged when sufficient, the test hand-held insulated tension pole of people (4) is aimed at capacitance type potential transformer (1) center flange P point and is clicked;

(6) observe pointer multimeter (2) personnel and observe, pointer multimeter (2) pointer is just referring to same polarity, otherwise is reversed polarity.