CN202093095U - Direct-current resistance tester for transformer - Google Patents

Abstract

The utility model provides a transformer DC resistance tester, the tester includes a central processing module; a current sampling module, the current sampling module is connected with the central processing module circuit; a voltage sampling module, the voltage sampling module is connected with the central processing module circuit connection; test power supply, a circuit is formed between the test power supply and the test power supply ground; and, a standard resistance, the standard resistance is set in the circuit between the test power supply and the test power supply ground; the current sampling module circuit is connected to the standard resistance Two ends; the circuit formed between the test power supply and the test power supply ground is also provided with an external transformer, and the voltage sampling module circuit is connected to the two ends of the winding of the transformer. The utility model reduces the repetitive workload of operators, improves work efficiency and shortens test time while saving human resources.

Description

A Transformer DC Resistance Tester

technical field

The utility model relates to a transformer resistance detection device, in particular to a transformer DC resistance tester.

Background technique

At present, with the rapid development of the economy, users have higher and higher requirements for power supply companies. Improving work efficiency and shortening maintenance and outage time are the basic requirements and key assessment indicators for power companies and residents. It is very important and urgent meaning. The transformer has many functions. It can not only increase the voltage to send electric energy to the power consumption area, but also reduce the voltage to the voltage of all levels to meet the needs of power consumption. Both step-up and step-down must be done by a transformer, and the transformer is used to increase the voltage and reduce the loss of power transmission.

In the current substation operation equipment, there are many and cumbersome test items belonging to transformer equipment, which account for a large amount of workload in daily work. The existing transformer electrical test equipment is basically an instrument that only has the test function of a single item. If several test contents need to be completed, it is necessary to repeatedly climb the transformer to change the wiring. In the test process, there are many links that need to be repeated. For example, there are more than a dozen test items for a 110kV transformer, and there are also more than a dozen instruments and meters brought to the site. During the test, the staff climbed up and down the transformer to change the test wiring. Once, completing the whole set of tests one by one will inevitably waste a lot of time, which will needlessly increase the workload of the operator, increase the probability of manual failure, and reduce work efficiency.

Utility model content

The utility model provides a transformer DC resistance tester, which can check various performance indexes of the transformer, reduce heavy work tasks and increase work effectiveness.

In order to achieve the above purpose, the utility model provides a transformer DC resistance tester, which is characterized in that the tester includes:

central processing module;

A current sampling module, the current sampling module is connected to the central processing module circuit;

A voltage sampling module, the voltage sampling module is connected to the central processing module circuit;

a test power supply in circuit with the test power supply ground; and,

A standard resistance, the standard resistance is set in the circuit between the test power supply and the test power supply ground; the current sampling module circuit is connected to both ends of the standard resistance;

An external transformer is also provided on the circuit formed between the above-mentioned test power supply and the test power supply ground, and the above-mentioned voltage sampling module circuit is connected to both ends of the winding of the transformer.

The above test power supply includes:

an operational amplifier, the negative input of which is grounded;

A digital potentiometer, the digital potentiometer circuit is connected to the positive input terminal of the operational amplifier; one end of the digital potentiometer is grounded;

An adjustment tube, the base circuit of the adjustment tube is connected to the output terminal of the operational amplifier; the emitter circuit of the adjustment tube is connected to the digital potentiometer;

A DC power supply, the DC power supply circuit is connected to the collector of the regulating tube;

A feedback resistor, the feedback resistor circuit is connected to the emitter of the adjustment tube;

A relay, the relay circuit is connected between the feedback resistor and the aforementioned transformer.

The DC power supply is connected to the test power supply, the test current is adjusted by adjusting the digital potentiometer, the relay is connected, and the test power supply is loaded on the transformer coil. After the transformer and the standard resistor are connected to the test power supply, the current sampling module detects the voltage on the standard resistor and transmits it to the central processing module. The central processing module calculates detect current. At the same time, the voltage sampling module detects the voltage on the transformer and transmits it to the central processing module. The central processing module collects the detected voltage on the transformer and the detected current obtained by the above calculation to calculate the DC resistance of the transformer.

Compared with the transformer detection technology of the prior art, the utility model transformer DC resistance tester has the advantages that the utility model effectively improves the precision and accuracy of the test, greatly reduces the repeated workload of operators, and also saves human resources At the same time, all the high and low voltage current and potential test lines can be connected to the transformer at one time, and there is no need to reverse the test lines during the test process, which increases the work efficiency and shortens the test time. The overall weight is greatly reduced and it is easy to carry. ,easy to use.

Description of drawings

Fig. 1 is the circuit block diagram of a kind of transformer DC resistance tester of the present utility model;

Fig. 2 is a schematic circuit diagram of a test power supply of a transformer DC resistance tester of the present invention.

Detailed ways

The specific embodiment of the utility model is described below in conjunction with accompanying drawing.

The utility model discloses a transformer direct current resistance tester, which effectively improves the precision and accuracy of the test, greatly reduces the repeated workload of operators, saves human resources, improves the work efficiency, and shortens the test time. time.

As shown in FIG. 1 , a transformer DC resistance tester includes a central processing module 1 , a current sampling module 2 , a voltage sampling module 3 , a test power supply 4 and a standard resistor 5 . The central processing module 1 adopts a CPU central processing unit, such as a CPU in a computer. The central processing module 1 is connected to the current sampling module 2 through two data transmission line circuits, and performs real-time information interaction with the current sampling module 2. The current sampling module 2 uses the AD7705 chip, and the AD7705 itself has filtering and amplification functions. For DC resistance sampling, use This chip has the characteristics of simple structure and high sampling precision.

The central processing module 1 is also connected to the voltage sampling module 3 through two data transmission line circuits, and performs information interaction with the voltage sampling module 3 in real time. The voltage sampling module 3 adopts an AD7705 chip.

The test power supply 4 is loaded on the coil of the transformer 6 to be tested externally, and one end of the coil of the transformer 6 is connected to the ground of the test power supply.

The standard resistor 5 and the coil of the transformer 6 are connected in series in the circuit of the test power supply 4, and the current sampling module 2 circuit is connected to both ends of the standard resistor 5 to detect the voltage on the standard resistor 5, and measure the voltage from the standard resistor 5. The obtained voltage and the resistance value of the standard resistor 5 can calculate the test current.

The circuit of the voltage sampling module 3 is connected to both ends of the coil of the transformer 6 to measure the voltage of the coil of the transformer 6 . The DC resistance of the transformer 6 can be calculated from the measured voltage of the coil of the transformer 6 and the above-mentioned calculated test current.

As shown in Figure 2, the test power supply 4 for the DC resistance test is a constant current source, which can quickly saturate the transformer coil and shorten the oscillation time of the inductance, which can increase the test speed. Within a certain range, the current remains constant regardless of the coil resistance. The test power supply 4 includes an operational amplifier 41 , a digital potentiometer 42 , an adjustment tube 43 , a DC power supply 44 , a feedback resistor 45 and a relay 46 . The negative input end of the operational amplifier 41 is grounded, the positive input end circuit is connected to the potential adjustment end of the digital potentiometer 42 , and the output end circuit is connected to the base of the adjustment tube 43 . Both ends of the digital potentiometer 42 are grounded respectively through a resistor, and are connected to the emitter of the adjusting tube 43 with the circuit. The collector circuit of the adjustment tube 43 is connected to the DC power supply 44 , the emitter circuit is connected to the feedback resistor 45 , the other end of the feedback resistor 45 is grounded, and the circuit is connected to the relay 46 , and the other end of the relay 46 is connected to the transformer 6 . The digital potentiometer 42 is used to set the size of the test current. The feedback resistor 45, the digital potentiometer 42 and the operational amplifier 41 form a current feedback control loop to keep the test current constant. The relay 46 is used to control the charging and discharging of the transformer 6 coils.

The operation process of a transformer DC resistance tester of the present invention will be described below in conjunction with the accompanying drawings.

Connect the DC power supply 44 in the test power supply 4, adjust the digital potentiometer 42, adjust the test current of the transformer DC resistance tester of the present utility model, and simultaneously feedback the resistance 45, the digital potentiometer 42, and the operational amplifier 41 to the test current feedback control. The relay 46 and the test power supply 4 are loaded on the coil of the transformer 6 . After the transformer 6 and the standard resistor 5 are connected to the test power supply 4, the current sampling module 2 detects the voltage on the standard resistor 5 and transmits it to the central processing module 1. voltage, the central processing module calculates the detection current.

On the other hand, the voltage sampling module 3 detects the voltage on the transformer 6, and transmits it to the central processing module 1, and the central processing module 1 collects the voltage detected on the transformer 6, and the above-mentioned detection current obtained by calculation, and calculates the DC voltage of the transformer 6. resistance.

Although the content of the present invention has been described in detail through the above preferred examples, it should be recognized that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions of the present utility model will be obvious to those skilled in the art after reading the above content. Therefore, the protection scope of the present utility model should be defined by the appended claims.

Claims (2)

1. a DC Resistance of Transformer tester is characterized in that, this tester comprises:

Central processing module (1);

Current sample module (2), this current sample module (2) is connected with described central processing module (1) circuit;

Voltage sample module (3), this voltage sample module (3) is connected with described central processing module (1) circuit;

Testing power supply (4), built-up circuit between this testing power supply (4) and the testing power supply ground; And,

Measuring resistance (5), this measuring resistance (5) are arranged in the circuit between testing power supply (4) and the testing power supply ground; Described current sample module (2) circuit is connected the two ends of this measuring resistance (5);

Also be provided with external transformer (6) between described testing power supply (4) and the testing power supply ground on the built-up circuit, described voltage sample module (3) circuit is connected the two ends of this transformer (6) winding.

2. a kind of DC Resistance of Transformer tester as claimed in claim 1 is characterized in that, described testing power supply (4) comprises:

Operational amplifier (41), the negative input ground connection of this operational amplifier (41);

Digital regulation resistance (42), the electrode input end of this digital regulation resistance (42) circuit concatenation operation amplifier (41); These digital regulation resistance (42) one end ground connection;

Adjust pipe (43), this adjusts the output terminal of the base circuit concatenation operation amplifier (41) of pipe (43); This emitter circuit of adjusting pipe (43) connects digital regulation resistance (42);

Direct supply (44), this direct supply (44) circuit connects the collector of adjusting pipe (43);

Feedback resistance (45), this feedback resistance (45) circuit connects the emitter of adjusting pipe (43);

Relay (46), this relay (46) circuit is connected between feedback resistance (45) and the described transformer (6).

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