CN205049726U - Take voltage transformer check gauge of temperature measurement function - Google Patents

Abstract

The utility model relates to the technical field of on-site measurement of power voltage transformers, in particular to a voltage transformer calibrator with a temperature measurement function. Including RC voltage divider circuit, rectifier filter circuit, 7805 voltage regulator circuit and electronic thermometer; RC voltage divider circuit, rectifier filter circuit and electronic thermometer are connected in parallel, the connection line of rectifier filter circuit and electronic thermometer is connected with 7805 stabilizer Voltage circuit, the other end of the 7805 voltage regulator circuit is connected to the power supply. The utility model can enable the test personnel to read the real-time temperature on site while conducting the test of the transformer ratio error and the phase error, so that the field test data of the voltage transformer is more scientific and accurate. At the same time, the power supply of the temperature module is taken from the transformer calibrator, which has a simple structure and saves costs, and can be widely used in power systems.

Description

A voltage transformer calibrator with temperature measurement function

technical field

The utility model relates to the technical field of on-site measurement of power voltage transformers, in particular to a voltage transformer calibrator with a temperature measurement function.

Background technique

According to the requirements of JJG314-2010 "Verification Regulations for Measuring Voltage Transformers", when conducting field tests on voltage transformers, it is necessary to measure the temperature conditions on site. However, due to the limitations of the test conditions on site and the negligence of the staff, the instant temperature of the test is often not measured.

The input voltage of an electronic thermometer is usually 5V, and it is usually impossible to directly provide a 5V power supply in field tests. The secondary voltage of the three-phase four-wire voltage transformer is usually When conducting a field test on a voltage transformer, it is necessary to connect the secondary voltage of the voltage transformer and the secondary terminal of the transformer calibrator in parallel. Therefore, the voltage across the secondary terminals of the transformer calibrator is also The secondary voltage of the transformer is reduced to 24V by the resistance-capacitance voltage divider circuit, and then the voltage is stepped down and stabilized by the DC stabilized power supply 7805, and the electronic thermometer can be powered by outputting 5V DC. Since the electronic thermometer is powered by the transformer secondary immediately during the transformer test, and is connected in parallel in the transformer calibrator, therefore, this paper proposes a voltage transformer calibrator with temperature measurement function, which can be used While conducting the transformer ratio error and phase error tests, the testers read the real-time temperature on site, making the field test data of voltage transformers more scientific and accurate.

Utility model content

Aiming at the problems existing in the above-mentioned prior art, the utility model provides a voltage transformer calibrator with temperature measurement function, the purpose is to provide a real-time on-site real-time Calibrator for accurate temperature readings and fast readings.

The technical scheme that the utility model solves its technical problem adopts is:

A voltage transformer calibrator with a temperature measurement function, comprising a resistance-capacitance divider circuit, a rectification filter circuit, a 7805 voltage stabilization circuit and an electronic thermometer; the resistance-capacity divider circuit, the rectification filter circuit and the electronic thermometer are connected in parallel, The connection line between the rectification filter circuit and the electronic thermometer is connected to a 7805 voltage stabilizing circuit, and the other end of the 7805 voltage stabilizing circuit is connected to a power supply.

The resistance-capacitance voltage divider circuit is composed of voltage-divider resistors R1 and R2 and voltage-divider capacitors C1 and C2; R1 and R2 are connected in series, and C1 and C2 are connected in series; the two series circuits are connected in parallel with each other and externally connected to the input voltage, while R2 and C2 are independently Parallel and external output voltage.

The rectification filter circuit adopts a single-phase full-wave bridge rectifier circuit; the full-wave bridge rectifier circuit is mainly composed of an integrated rectifier diode, a filter capacitor C ₀ , and a load resistor R ₀ ; the input terminal of the integrated rectifier diode is used as the bridge rectifier circuit input , the output terminal of the integrated rectifier diode is connected in parallel with the filter capacitor C ₀ and the load resistor R ₀ as the output terminal of the bridge rectifier circuit.

The integrated rectifier diode is 1N4007, with a forward surge current of 30A, a limit VRM ≥ 50V, and a maximum reverse withstand voltage of 1000V.

The calibrator is to connect the temperature measuring device to the transformer calibrator through the insulated wire, and connect it in parallel with the secondary terminal of the standard voltage transformer. When performing field tests to read the ratio difference and phase difference of the transformer, it can read Take the real-time temperature at the site; the specific wiring method is: the high voltage side of the transformer, the primary side of the standard voltage transformer, and the primary side of the tested voltage transformer are connected in parallel; the high-end a and low-side x of the secondary side of the standard voltage transformer are connected to the transformer calibrator The two ends of V are used as the power supply voltage circuit; the low end x of the secondary side of the standard voltage transformer and the low end x of the secondary side of the tested voltage transformer are respectively connected to the two ends of △V of the transformer calibrator as a differential voltage circuit; The high end a of the secondary side of the voltage transformer is connected to the high end a of the secondary side of the tested voltage transformer.

The calibrator is first connected in parallel with the temperature measuring device into the standard transformer jack of the transformer calibrator by using the insulated wire access method; at this time, the temperature measuring device can be regarded as a part of the transformer calibrator , that is, the calibrator is a transformer calibrator with temperature measurement function; when the field test is carried out, the primary voltage of the transformer is boosted, and due to the step-down effect of the transformer, the secondary voltage of the transformer is generated Voltage, the power supply is provided through the terminal connected in parallel with it on the transformer calibrator, and the 5V voltage is generated by the resistance-capacitance voltage divider circuit, rectification filter circuit and 7805 voltage regulator circuit to complete the power supply for the electronic thermometer.

The beneficial effects of the utility model are:

The utility model can enable the test personnel to read the real-time temperature on site while conducting the test of the transformer ratio error and the phase error, so that the field test data of the voltage transformer is more scientific and accurate. At the same time, the power supply of the temperature module is taken from the transformer calibrator, which has a simple structure and saves costs, and can be widely used in power systems.

Below in conjunction with accompanying drawing and example the utility model is described in further detail.

Description of drawings

Fig. 1 is a system position diagram of the present utility model;

Fig. 2 is a simplified structural diagram of the utility model temperature measuring device;

Fig. 3 is the resistance-capacitance voltage divider circuit diagram of the utility model;

Fig. 4 is a circuit diagram of rectification and filtering of the utility model.

detailed description

The utility model is a voltage transformer calibrator with a temperature measurement function, specifically a temperature measuring device connected in parallel in the secondary circuit of a standard voltage transformer, which can realize the real-time reading of the field while performing field error inspection. temperature.

The calibrator of the utility model is mainly composed of a resistor-capacitor voltage divider circuit, a rectifier filter circuit, a 7805 voltage regulator circuit and an electronic thermometer, and its simplified structure diagram is shown in Figure 2. The resistance-capacity voltage divider circuit, the rectification filter circuit and the electronic thermometer are connected in parallel, the connection line between the rectification filter circuit and the electronic thermometer is connected to a 7805 voltage stabilizing circuit, and the other end of the 7805 voltage stabilizing circuit is connected to a power supply.

The RC voltage divider circuit is composed of voltage divider resistors R1 and R2 and voltage divider capacitors C1 and C2. R1 and R2 are connected in series, and C1 and C2 are connected in series; the two series circuits are connected in parallel with each other and connected with an external input voltage, while R2 and C2 are connected in parallel with each other and connected with an external output voltage.

The structural diagram is shown in Figure 3. This circuit generates the transformer secondary The voltage outputs 12V DC voltage through voltage division, so through verification, the size of R1 is 4kΩ, and the size of R2 is 1kΩ; the main function of the voltage division capacitor is to eliminate the influence of distributed capacitance, which needs to satisfy R1×C1=R2×C2, and pass the verification of the size of C1 is 1000pF, and the size of C2 is 4000pF.

The rectification and filtering circuit adopts a single-phase full-wave bridge rectification circuit, and the structure diagram is shown in FIG. 4 . The full-wave bridge rectifier circuit is mainly composed of an integrated rectifier diode, a filter capacitor C ₀ , and a load resistor R ₀ . The input terminal of the integrated rectifier diode is used as the input of the bridge rectifier circuit, and the output terminal of the integrated rectifier diode is connected in parallel with the filter capacitor C ₀ and the load resistance R ₀ as the output terminal of the bridge rectifier circuit. The integrated rectifier diode adopts 1N4007, the forward surge current is 30A, the limit VRM is ≥ 50V, and the highest reverse withstand voltage is 1000V. It has a large forward surge current and reverse withstand voltage and is low in cost. The rectifier bridge outputs an average voltage value 0.9V ₂ is about 10.8V, which ensures that the 7805 voltage regulator circuit can work well; the function of the capacitor C ₀ is smoothing and filtering, and its parameter is 1000pF; the load resistance R ₀ needs to be connected to the load 7805 in actual use, so it is not necessary to connect it .

The system wiring diagram of the utility model is shown in Figure 1. The temperature measuring device is connected to the transformer calibrator through an insulated wire, and is connected in parallel with the secondary terminal of the standard voltage transformer. When the field test is performed, the ratio difference and phase of the transformer are read. At the same time, the real-time temperature on site can be read. The specific wiring method is: the high-voltage side of the transformer, the primary side of the standard voltage transformer, and the primary side of the tested voltage transformer are connected in parallel; the high-end a and low-side x of the secondary side of the standard voltage transformer are connected to the two ends of the transformer calibrator V as power supply Voltage loop; the low end x of the secondary side of the standard voltage transformer and the low end x of the secondary side of the tested voltage transformer are respectively connected to the two ends of the transformer calibrator △V, as a differential voltage loop; the secondary side of the standard voltage transformer The high end a is connected to the high end a of the secondary side of the voltage transformer under test.

During specific implementation, as shown in Fig. 1, Fig. 1 is a system position diagram of the present invention, taking low potential measurement error as an example.

First, connect the temperature measuring device in parallel to the standard transformer jack of the transformer calibrator by using the insulated wire access method. At this time, the temperature measuring device can be regarded as a part of the transformer calibrator, that is, the calibrator is a transformer calibrator with a temperature measurement function. When the field test is carried out, the primary voltage of the transformer is boosted, and due to the depressurization effect of the transformer, the secondary voltage of the transformer is generated Voltage, the power supply is provided through the terminal connected in parallel with it on the transformer calibrator, and the 5V voltage is generated by the resistance-capacitance voltage divider circuit, rectification filter circuit and 7805 voltage regulator circuit to complete the power supply for the electronic thermometer.

Claims (6)

1. the voltage transformer (VT) tester with temperature measurement function, is characterized in that: comprise resistive-capacitive voltage divider circuit, current rectifying and wave filtering circuit, 7805 mu balanced circuits and electronic temp meter; Resistive-capacitive voltage divider circuit, current rectifying and wave filtering circuit and electronic temp meter are connected in parallel, and current rectifying and wave filtering circuit is connected 7805 mu balanced circuits with in the connecting line of electronic temp meter, and the 7805 mu balanced circuit other ends connect power supply.

2. a kind of voltage transformer (VT) tester with temperature measurement function according to claim 1, is characterized in that: described resistive-capacitive voltage divider circuit is made up of divider resistance R1 and R2 and derided capacitors C1 and C2; R1 and R2 connects, C1 and C2 connects; Two series circuits are connected in parallel to each other and external input voltage, simultaneously in parallel separately the and external output voltage of R2 and C2.

3. a kind of voltage transformer (VT) tester with temperature measurement function according to claim 1, is characterized in that: described current rectifying and wave filtering circuit adopts single phase full wave bridge rectifying; Full-wave bridge rectifier circuit is primarily of integrated commutation diode, filter capacitor C ₀, pull-up resistor R ₀composition; Integrated commutation diode input end inputs as bridge rectifier circuit, integrated commutation diode output terminal and filter capacitor C ₀, pull-up resistor R ₀parallel connection, as bridge rectifier circuit output terminal.

4. a kind of voltage transformer (VT) tester with temperature measurement function according to claim 3, is characterized in that: described integrated commutation diode adopts 1N4007, surge forward current 30A, limit VRM >=50V, the highest reverse withstand voltage 1000V.

5. a kind of voltage transformer (VT) tester with temperature measurement function according to claim 1, it is characterized in that: described tester is that temperature measuring equipment is accessed mutual-inductor tester through insulated conductor, in parallel with standard potential transformer secondary terminals, on-the-spot real-time temperature can be read while the ratio difference of carrying out site test reading mutual inductor and phase differential; The concrete mode of connection is: high voltage side of transformer, standard potential transformer primary side, the parallel connection of tested voltage transformer (VT) primary side; The high-end a of standard potential transformer secondary side and low side x connects mutual-inductor tester V two ends, as supply voltage loop; Standard potential transformer secondary side low side x and tested voltage transformer secondary side low side x connects mutual-inductor tester △ V two ends, respectively as error of measurement voltage circuit; The high-end a of standard potential transformer secondary side is connected with the high-end a of tested voltage transformer secondary side.

6. a kind of voltage transformer (VT) tester with temperature measurement function according to claim 1, is characterized in that: described tester first adopts insulated conductor access way by temperature measuring equipment parallel connection access mutual-inductor tester standard mutual inductor jack; Now, temperature measuring equipment can regard a part for mutual-inductor tester as, and namely tester is the mutual-inductor tester of band temperature measurement function; When carrying out site test, once boosting to mutual inductor, due to the hypotensive effect of mutual inductor, mutual inductor secondary produces voltage, provides power supply by terminal in parallel with it on mutual-inductor tester, and through resistive-capacitive voltage divider circuit, current rectifying and wave filtering circuit and 7805 mu balanced circuits produce 5V voltage, complete the power supply to electronic temp meter.