Substation electric power secondary test device

Abstract

The utility model relates to an electric power secondary test device for a transformer substation, which is used for testing a voltage transformer and comprises a portable case, and a single chip microcomputer, an insulation resistance measuring circuit, an induction withstand voltage test circuit, a no-load current detection circuit and a transformation ratio test circuit which are arranged in the portable case, the insulation resistance measuring circuit, the induction withstand voltage test circuit, the no-load current detection circuit and the transformation ratio test circuit are all connected with the single-chip microcomputer. According to the utility model, the insulation resistance measuring circuit, the induction withstand voltage test circuit, the no-load current detection circuit and the transformation ratio test circuit are integrated in the portable case, so that insulation resistance measurement, induction withstand voltage test, no-load current detection and transformation ratio test can be carried out on the voltage transformer, a test instrument does not need to be replaced, the operation is convenient, and the cost is low. And the test efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the field of transformer substation testing, in particular to a transformer substation power secondary testing device. Background Art

[0002] Substation secondary equipment primarily includes measuring instruments, signal systems, and relay protection, and voltage transformers are a crucial component of these systems. Similar to transformers, voltage transformers are instruments used to transform voltage, but their primary purpose is to power measuring instruments and relay protection devices, measuring the voltage, power, and energy of a line, or protecting valuable equipment, motors, and transformers in the event of a fault. Voltage transformers provide the necessary voltage signals and data to ensure the safe and stable operation of the power system, and therefore require regular testing. Voltage transformers can be tested for a variety of purposes, but existing technologies require different test tools for different test purposes, which can be inconvenient for testers. Utility Model Content

[0003] The utility model provides a transformer substation power secondary test device to solve the problem in the prior art that different test tools need to be replaced for different test contents of a voltage transformer, thus causing inconvenience in operation.

[0004] The utility model provides a technical solution to the above-mentioned technical problems as follows: a substation power secondary test device for testing a voltage transformer, comprising a portable chassis and a single-chip microcomputer, an insulation resistance measurement circuit, an inductive withstand voltage test circuit, a no-load current detection circuit and a transformation ratio test circuit arranged in the portable chassis; the insulation resistance measurement circuit, the inductive withstand voltage test circuit, the no-load current detection circuit and the transformation ratio test circuit are all connected to the single-chip microcomputer.

[0005] On the basis of the above technical solution, the present invention can also be improved as follows.

[0006] Furthermore, the insulation resistance measurement circuit includes a DC voltage generating circuit and a sampling circuit; the input end of the DC voltage generating circuit is connected to the signal output end of the single-chip microcomputer, the output end of the DC voltage generating circuit is connected to the input end of the sampling circuit, the output end of the sampling circuit is connected to the signal input end of the single-chip microcomputer, and the sampling circuit is provided with an insulation resistance test interface.

[0007] Furthermore, the DC voltage generating circuit includes a pulse width modulation circuit, a boost transformer and a voltage doubler rectifier circuit; the input end of the pulse width modulation circuit is connected to the signal output end of the single-chip microcomputer, the output end of the pulse width modulation circuit is connected to the primary coil of the boost transformer, the secondary coil of the boost transformer is connected to the input end of the voltage doubler rectifier circuit, and the output end of the voltage doubler rectifier circuit is connected to the signal input end of the single-chip microcomputer.

[0008] Furthermore, the insulation resistance test interface includes a first insulation resistance test interface and a second insulation resistance test interface; the sampling circuit includes:

[0009] a first resistor, one end of which is connected to the output end of the DC voltage generating circuit, and the other end of which is connected to the first insulation resistance test interface;

[0010] a second resistor, one end of which is connected to the first insulation resistance test interface;

[0011] a third resistor, one end of which is connected to the other end of the second resistor and the signal input end of the single chip microcomputer, and the other end of which is grounded;

[0012] A fourth resistor has one end connected to the second insulation resistance test interface and the signal input end of the single chip microcomputer, and the other end grounded.

[0013] Furthermore, the induced voltage withstand test circuit includes an adjustable voltage output circuit, a breakdown detection circuit and a feedback circuit; the output end of the adjustable voltage output circuit is connected to the secondary coil of the voltage transformer to be tested, the detection electrode of the breakdown detection circuit is arranged in the insulating medium inside the voltage transformer to be tested, the output end of the breakdown detection circuit is connected to the controlled end of the adjustable voltage output circuit, the input end of the feedback circuit is connected to the output end of the breakdown detection circuit, and the output end of the feedback circuit is connected to the signal input end of the microcontroller.

[0014] Furthermore, the secondary of the voltage transformer to be tested is also provided with a non-pressurized secondary coil; the inductive withstand voltage test circuit also includes an adjustable inductor, and both ends of the adjustable inductor are connected to both ends of the non-pressurized secondary coil.

[0015] Furthermore, the no-load current detection circuit includes:

[0016] A first variable resistor, two fixed ends of which are used to connect the positive and negative poles of a power supply;

[0017] a first switch, one end of which is connected to the moving end of the first variable resistor;

[0018] an ammeter, one end of which is connected to the other end of the first switch;

[0019] a first voltmeter, one end of which is connected to the other end of the ammeter, and the other end of which is connected to a certain end of the first variable resistor;

[0020] a first linkage switch connected to both ends of the first voltmeter;

[0021] When performing no-load current detection, the primary coil of the voltage transformer to be tested is connected to both ends of the first voltmeter through the first linkage switch;

[0022] The ammeter and the first voltmeter are both digital instruments, and are connected to the signal input terminal of the single chip microcomputer.

[0023] Furthermore, the transformation ratio test circuit includes:

[0024] The second variable resistor has two fixed ends for connecting the positive and negative electrodes of the power supply;

[0025] a second switch, one end of which is connected to the movable end of the second variable resistor;

[0026] a second voltmeter, one end of which is connected to a certain end of the second variable resistor, and the other end of which is connected to the other end of the second switch;

[0027] a second linkage switch connected to both ends of the second voltmeter; when performing a transformation ratio test, the primary coil of the voltage transformer to be tested is connected to both ends of the second voltmeter via the second linkage switch;

[0028] The transformation ratio test circuit further includes a third voltmeter, wherein both ends of the third voltmeter are connected to both ends of the secondary coil of the voltage transformer;

[0029] The second voltmeter and the third voltmeter are both digital meters, and are connected to the signal input terminal of the single chip microcomputer.

[0030] Furthermore, a display screen is embedded on the surface of the portable chassis, and the display screen is connected to the single chip microcomputer.

[0031] Furthermore, the single chip microcomputer is equipped with a communication module, and the single chip microcomputer is connected to a remote host computer through the communication module.

[0032] The beneficial effects of the utility model are as follows: the utility model is a substation power secondary test device which integrates an insulation resistance measurement circuit, an inductive withstand voltage test circuit, a no-load current detection circuit and a transformation ratio test circuit in a portable chassis, and can perform insulation resistance measurement, inductive withstand voltage test, no-load current detection and transformation ratio test on a voltage transformer without the need to replace the test instrument, is easy to operate and improves test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a block diagram of the overall structure of the internal circuit of a substation power secondary test device of the utility model;

[0034] Figure 2 It is a structural diagram of the insulation resistance measurement circuit;

[0035] Figure 3 It is a structural diagram of the inductive voltage withstand test circuit;

[0036] Figure 4 It is a structural diagram of the no-load current detection circuit;

[0037] Figure 5 This is a structural diagram of the ratio test circuit. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0039] like Figure 1 As shown, a substation power secondary test device is used to test a voltage transformer, including a portable chassis and a single-chip microcomputer, an insulation resistance measurement circuit, an inductive withstand voltage test circuit, a no-load current detection circuit and a transformation ratio test circuit arranged in the portable chassis; the insulation resistance measurement circuit, the inductive withstand voltage test circuit, the no-load current detection circuit and the transformation ratio test circuit are all connected to the single-chip microcomputer.

[0040] The utility model discloses a substation power secondary test device which integrates an insulation resistance measurement circuit, an inductive withstand voltage test circuit, a no-load current detection circuit and a transformation ratio test circuit in a portable chassis. It can perform insulation resistance measurement, inductive withstand voltage test, no-load current detection and transformation ratio test on a voltage transformer without the need to replace test instruments, is easy to operate and improves test efficiency.

[0041] In this specific embodiment, Figure 2 As shown: the insulation resistance measurement circuit includes a DC voltage generating circuit and a sampling circuit; the input end of the DC voltage generating circuit is connected to the signal output end of the single-chip microcomputer, the output end of the DC voltage generating circuit is connected to the input end of the sampling circuit, the output end of the sampling circuit is connected to the signal input end of the single-chip microcomputer, and the sampling circuit is provided with an insulation resistance test interface.

[0042] Preferably, the DC voltage generating circuit includes a pulse width modulation circuit, a boost transformer and a voltage doubler rectifier circuit; the input end of the pulse width modulation circuit is connected to the signal output end of the single-chip microcomputer, the output end of the pulse width modulation circuit is connected to the primary coil of the boost transformer, the secondary coil of the boost transformer is connected to the input end of the voltage doubler rectifier circuit, and the output end of the voltage doubler rectifier circuit is connected to the signal input end of the single-chip microcomputer.

[0043] Preferably, the insulation resistance test interface includes a first insulation resistance test interface and a second insulation resistance test interface; the sampling circuit includes:

[0044] A first resistor R1, one end of which is connected to the output end of the DC voltage generating circuit, and the other end of which is connected to the first insulation resistance test interface J1;

[0045] A second resistor R2, one end of which is connected to the first insulation resistance test interface J1;

[0046] a third resistor R3, one end of which is connected to the other end of the second resistor R2 and the signal input end of the single chip microcomputer, and the other end of which is grounded;

[0047] The fourth resistor R4 has one end connected to the second insulation resistance test interface J2 and the signal input terminal of the single chip microcomputer, and the other end grounded.

[0048] In the insulation resistance measurement circuit, the DC voltage generating circuit outputs a DC high voltage as a test voltage; in the sampling circuit, Rx is the insulation resistance to be measured in the voltage transformer; the reference voltage is between the second resistor R2 and the third resistor R3, and the sampling voltage is between the fourth resistor R4 and the second insulation resistance test interface J2; when the test voltage changes significantly, the sampling voltage and the reference voltage change synchronously, and the change in the measurement voltage has basically no effect on the measurement result. Therefore, using the sampling circuit for insulation resistance testing can greatly improve measurement stability and measurement accuracy.

[0049] In this specific embodiment, Figure 3 As shown: the induced voltage withstand test circuit includes an adjustable voltage output circuit, a breakdown detection circuit and a feedback circuit; the output end of the adjustable voltage output circuit is connected to the secondary coil of the voltage transformer to be tested, the detection electrode of the breakdown detection circuit is arranged in the insulating medium inside the voltage transformer to be tested, the output end of the breakdown detection circuit is connected to the controlled end of the adjustable voltage output circuit, the input end of the feedback circuit is connected to the output end of the breakdown detection circuit, and the output end of the feedback circuit is connected to the signal input end of the microcontroller.

[0050] Preferably, the secondary of the voltage transformer to be tested is further provided with a non-pressurized secondary coil; the inductive withstand voltage test circuit further comprises an adjustable inductor, and both ends of the adjustable inductor are connected to both ends of the non-pressurized secondary coil.

[0051] In the inductive withstand voltage test circuit, the adjustable voltage output circuit provides an adjustable voltage seat withstand voltage test voltage. The breakdown detection circuit can detect whether the voltage transformer breaks down under the action of the withstand voltage test voltage, and outputs a breakdown signal when it breaks down to control the adjustable voltage output circuit to stop outputting the withstand voltage test voltage to ensure safety. At the same time, the feedback circuit feeds back the breakdown signal to the microcontroller, and the microcontroller records the withstand voltage test voltage of the voltage transformer.

[0052] Furthermore, due to its structure, the primary winding of the voltage transformer has a stray capacitance to ground. This stray capacitance can cause the current flowing through the pressurized secondary coil to be very high during an on-site inductive withstand voltage test of the voltage transformer, exceeding the cross-sectional area of ​​the secondary coil and preventing the test from being completed properly. To address this issue, an adjustable inductor is added to the inductive withstand voltage test circuit to compensate for the capacitive current caused by the stray capacitance. This reduces the current flowing through the pressurized secondary coil during the test, allowing the test to be completed successfully.

[0053] In this specific embodiment, Figure 4 As shown: the no-load current detection circuit includes:

[0054] The first variable resistor Rp1 has two fixed ends for connecting the positive and negative electrodes of the power supply;

[0055] A first switch K1, one end of which is connected to the movable end of the first resistor Rp1;

[0056] an ammeter A, one end of which is connected to the other end of the first switch K1;

[0057] a first voltmeter V1, one end of which is connected to the other end of the ammeter A, and the other end of which is connected to a certain end of the first variable resistor Rp1;

[0058] A first linkage switch K2 is connected to both ends of the first voltmeter V1;

[0059] When performing no-load current detection, the primary coil of the voltage transformer VT to be tested is connected to both ends of the first voltmeter V1 through the first linkage switch K2;

[0060] The ammeter A and the first voltmeter V1 are both digital instruments, and are connected to the signal input terminal of the single chip microcomputer.

[0061] In the no-load current detection circuit, the resistance of the first variable resistor Rp1 is changed to modulate different voltages, thereby performing a no-load current detection test. During the test, the test results are directly obtained through the ammeter A and the first voltmeter V1.

[0062] In this specific embodiment, Figure 5 As shown: the transformation ratio test circuit includes:

[0063] The second variable resistor Rp2 has two fixed ends for connecting the positive and negative poles of the power supply;

[0064] A second switch K3, one end of which is connected to the movable end of the second resistor Rp2;

[0065] a second voltmeter V2, one end of which is connected to a certain end of the second variable resistor Rp2, and the other end of which is connected to the other end of the second switch K3;

[0066] The second linkage switch K4 is connected to both ends of the second voltmeter V2; when performing a transformation ratio test, the primary coil of the voltage transformer VT to be tested is connected to both ends of the second voltmeter V2 through the second linkage switch K4;

[0067] The transformation ratio test circuit further includes a third voltmeter V3, the two ends of which are connected to the two ends of the secondary coil of the voltage transformer VT;

[0068] The second voltmeter V2 and the third voltmeter V3 are both digital meters, and are connected to the signal input terminal of the single chip microcomputer.

[0069] In the ratio test circuit, the resistance of the second variable resistor Rp2 is changed to modulate different voltages, thereby performing a ratio test. During the test, the test results are directly obtained through the second voltmeter V2 and the third voltmeter V3.

[0070] In this specific embodiment, the portable case is inlaid with a display screen, which is connected to the single-chip microcomputer. The single-chip microcomputer is equipped with a communication module, which is connected to a remote host computer through the communication module.

[0071] In the utility model, a display screen is embedded in the surface of the portable chassis, and the display screen is connected to the single-chip microcomputer, so that the test data can be viewed locally; in addition, the single-chip microcomputer is connected to the remote host computer through a communication module, and the test data such as insulation resistance measurement, induced voltage withstand test, no-load current detection and ratio test can be uploaded to the host computer for remote viewing.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A substation power secondary test device, characterized in that: Used to test a voltage transformer, comprising a portable chassis and a single-chip microcomputer, an insulation resistance measurement circuit, an inductive withstand voltage test circuit, a no-load current detection circuit, and a transformation ratio test circuit arranged in the portable chassis; the insulation resistance measurement circuit, the inductive withstand voltage test circuit, the no-load current detection circuit, and the transformation ratio test circuit are all connected to the single-chip microcomputer; The insulation resistance measurement circuit includes a DC voltage generating circuit and a sampling circuit; the input end of the DC voltage generating circuit is connected to the signal output end of the single-chip microcomputer, the output end of the DC voltage generating circuit is connected to the input end of the sampling circuit, the output end of the sampling circuit is connected to the signal input end of the single-chip microcomputer, and the sampling circuit is provided with an insulation resistance test interface; The DC voltage generating circuit includes a pulse width modulation circuit, a boost transformer and a voltage doubling rectifier circuit; the input end of the pulse width modulation circuit is connected to the signal output end of the single-chip microcomputer, the output end of the pulse width modulation circuit is connected to the primary coil of the boost transformer, the secondary coil of the boost transformer is connected to the input end of the voltage doubling rectifier circuit, and the output end of the voltage doubling rectifier circuit is connected to the signal input end of the single-chip microcomputer; The insulation resistance test interface includes a first insulation resistance test interface and a second insulation resistance test interface; The sampling circuit comprises: a first resistor, one end of which is connected to the output end of the DC voltage generating circuit, and the other end of which is connected to the first insulation resistance test interface; a second resistor, one end of which is connected to the first insulation resistance test interface; a third resistor, one end of which is connected to the other end of the second resistor and the signal input end of the single chip microcomputer, and the other end of which is grounded; A fourth resistor has one end connected to the second insulation resistance test interface and the signal input end of the single chip microcomputer, and the other end grounded.

2. The substation power secondary test device according to claim 1, characterized in that: The inductive voltage withstand test circuit includes an adjustable voltage output circuit, a breakdown detection circuit and a feedback circuit; the output end of the adjustable voltage output circuit is connected to the secondary coil of the voltage transformer to be tested, the detection electrode of the breakdown detection circuit is arranged in the insulating medium inside the voltage transformer to be tested, the output end of the breakdown detection circuit is connected to the controlled end of the adjustable voltage output circuit, the input end of the feedback circuit is connected to the output end of the breakdown detection circuit, and the output end of the feedback circuit is connected to the signal input end of the single-chip microcomputer.

3. The substation power secondary test device according to claim 2, characterized in that: The secondary of the voltage transformer to be tested is also provided with a non-pressurized secondary coil; the induction withstand voltage test circuit also includes an adjustable inductor, and the two ends of the adjustable inductor are connected to the two ends of the non-pressurized secondary coil.

4. The substation power secondary test device according to claim 1, characterized in that: The no-load current detection circuit includes: A first variable resistor, two fixed ends of which are used to connect the positive and negative poles of a power supply; a first switch, one end of which is connected to the moving end of the first variable resistor; an ammeter, one end of which is connected to the other end of the first switch; a first voltmeter, one end of which is connected to the other end of the ammeter, and the other end of which is connected to a certain end of the first variable resistor; a first linkage switch connected to both ends of the first voltmeter; When performing no-load current detection, the primary coil of the voltage transformer to be tested is connected to both ends of the first voltmeter through the first linkage switch; The ammeter and the first voltmeter are both digital instruments, and are connected to the signal input terminal of the single chip microcomputer.

5. The substation power secondary test device according to claim 1, characterized in that: The transformation ratio test circuit comprises: The second variable resistor has two fixed ends for connecting the positive and negative electrodes of the power supply; a second switch, one end of which is connected to the movable end of the second variable resistor; a second voltmeter, one end of which is connected to a certain end of the second variable resistor, and the other end of which is connected to the other end of the second switch; a second linkage switch connected to both ends of the second voltmeter; when performing a transformation ratio test, the primary coil of the voltage transformer to be tested is connected to both ends of the second voltmeter via the second linkage switch; The transformation ratio test circuit further includes a third voltmeter, wherein both ends of the third voltmeter are connected to both ends of the secondary coil of the voltage transformer; The second voltmeter and the third voltmeter are both digital meters, and are connected to the signal input terminal of the single chip microcomputer.

6. The substation power secondary test device according to claim 1, characterized in that: A display screen is inlaid on the surface of the portable case, and the display screen is connected to the single chip microcomputer.

7. The substation power secondary test device according to claim 1, characterized in that: The single chip microcomputer is equipped with a communication module, and the single chip microcomputer is connected to a remote host computer through the communication module.

Images