阅读说明：本技术 一种电压互感器二次电压检测装置及检测方法 (Secondary voltage detection device and detection method for voltage transformer ) 是由 卢润波 周梓俊 张建华 叶灿伦 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种电压互感器二次电压检测装置及检测方法,主控制器与输入切换模块电连接,输入切换模块与分压模块电连接,分压模块与全波整流模块电连接,全波整流模块与模数转换模块电连接,模数转换模块与主控制器电连接；主控制器控制输入切换模块采集各相线输入电压；分压模块对相线输入电压进行降压处理；全波整流模块将相线输入电压转化成直流电压；模数转换模块将直流电压转为数字信号；主控制器在数字信号大于设定阈值时,确定电压互感器二次电压异常。本发明提供的技术方案,可实现电压互感器二次电压的自动化检测,提高检测的精准性和效率。(The invention discloses a secondary voltage detection device and a detection method of a voltage transformer.A main controller is electrically connected with an input switching module, the input switching module is electrically connected with a voltage dividing module, the voltage dividing module is electrically connected with a full-wave rectification module, the full-wave rectification module is electrically connected with an analog-to-digital conversion module, and the analog-to-digital conversion module is electrically connected with the main controller; the main controller controls the input switching module to collect input voltage of each phase line; the voltage division module performs voltage reduction processing on the phase line input voltage; the full-wave rectification module converts the input voltage of the phase line into direct-current voltage; the analog-to-digital conversion module converts the direct-current voltage into a digital signal; and when the digital signal is greater than a set threshold value, the main controller determines that the secondary voltage of the voltage transformer is abnormal. According to the technical scheme provided by the invention, the automatic detection of the secondary voltage of the voltage transformer can be realized, and the detection accuracy and efficiency are improved.)

1. A secondary voltage detection device of a voltage transformer is characterized by comprising a main controller, an input switching module, a voltage division module, a full-wave rectification module and an analog-to-digital conversion module; the main controller is electrically connected with the input switching module, the input switching module is electrically connected with the voltage dividing module, the voltage dividing module is electrically connected with the full-wave rectification module, the full-wave rectification module is electrically connected with the analog-to-digital conversion module, and the analog-to-digital conversion module is electrically connected with the main controller;

the main controller is used for controlling the input switching module to switch the input voltage of each phase line of the acquisition cable; the voltage division module is used for carrying out voltage reduction processing on the input voltage of the phase line; the full-wave rectification module is used for converting the phase line input voltage subjected to voltage reduction processing by the voltage division module into direct-current voltage; the analog-to-digital conversion module is used for converting the direct-current voltage into a digital signal; and the main controller is also used for determining that the secondary voltage of the voltage transformer is abnormal when the digital signal is greater than a set threshold value.

2. The secondary voltage detection device of claim 1, wherein said input switching module comprises at least two switching circuits; each switching circuit comprises a power supply end, an acquisition end, an output end and a control end;

the power end of each switching circuit is connected with an external power supply; the acquisition ends of the switching circuits are connected with the phase lines of the cable in a one-to-one correspondence manner; the output end of each switching circuit is electrically connected with the voltage division module; the control end of each switching circuit is electrically connected with the main controller; the main controller is used for controlling the switching circuits to be sequentially conducted with the voltage division module.

3. The voltage transformer secondary voltage detection device according to claim 2, wherein the switching circuit further includes a relay and a transistor;

the control end of the switching circuit is electrically connected with the control end of the transistor; a first end of a coil of the relay is electrically connected with the power supply end of the switching circuit, a second end of the coil of the relay is electrically connected with an input end of the transistor, and an output end of the transistor is grounded; the first end of the switch of the relay is electrically connected with the acquisition end of the switching circuit, and the second end of the switch of the relay is electrically connected with the output end of the switching circuit.

4. The secondary voltage detecting device of claim 3, wherein said transistor comprises an NPN transistor.

5. The secondary voltage detecting device of claim 3, wherein said switching circuit further comprises a first current limiting resistor, a second current limiting resistor and a first diode;

the control end of the switching circuit is electrically connected with the control end of the transistor through the first current limiting resistor; the output end of the transistor is grounded through the second current-limiting resistor; the positive electrode of the first diode is electrically connected with the second end of the coil of the relay, and the negative electrode of the first diode is electrically connected with the first end of the coil of the relay.

6. The secondary voltage detection device of the voltage transformer according to claim 1, wherein the voltage division module comprises a transformer, a first capacitor, a second capacitor and a divided voltage output end;

the first end of the high-voltage side of the transformer is electrically connected with the input switching module, and the second end of the high-voltage side of the transformer is electrically connected with the reference voltage end; the first end of the low-voltage side of the transformer is electrically connected with the first end of the first capacitor, and the second end of the low-voltage side of the transformer is grounded; the second end of the first capacitor and the first end of the second capacitor are both electrically connected with the divided voltage output end, and the second end of the second capacitor is grounded; the divided voltage output end is electrically connected with the full-wave rectification module.

7. The secondary voltage detection device of the voltage transformer according to claim 1, wherein the full-wave rectification module comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a second diode, a third diode, a first operational amplifier and a second operational amplifier;

a first end of the first resistor and a first end of the fourth resistor are connected to a first node, a second end of the first resistor and a first end of the second resistor are connected to a second node, the second resistor and a first end of the third resistor are connected to a third node, and a second end of the third resistor and a second end of the fourth resistor are connected to a fourth node; a first end of the fifth resistor is electrically connected with the fourth node, and a second end of the fifth resistor is electrically connected with the analog-to-digital conversion module;

the inverting input end of the first operational amplifier and the cathode of the third diode are both electrically connected with the second node; the non-inverting input end of the first operational amplifier is grounded; the output end of the first operational amplifier and the anode of the third diode are both electrically connected with the cathode of the second diode; the anode of the second diode is electrically connected with the third node;

the inverting input end of the second operational amplifier is electrically connected with the fourth node, the non-inverting input end of the second operational amplifier is grounded, and the output end of the second operational amplifier is electrically connected with the second end of the fifth resistor.

8. The secondary voltage detection device of a voltage transformer according to claim 1, further comprising a display; the display is electrically connected with the main controller.

9. The secondary voltage detecting device of a voltage transformer according to claim 8, further comprising a printer; the printer is electrically connected with the main controller.

10. A secondary voltage detection method for a voltage transformer, which is applied to the secondary voltage detection device for a voltage transformer according to any one of claims 1 to 9, the secondary voltage detection method for a voltage transformer comprising:

the input switching module is controlled to switch and collect input voltages of phase lines of the cable;

acquiring digital signals which are subjected to voltage reduction treatment by a voltage division module, converted from alternating current to direct current by a full-wave rectification module and converted by an analog-to-digital conversion module in sequence;

and when the digital signal is greater than a set threshold value, determining that the secondary voltage of the voltage transformer is abnormal.

Technical Field

The invention relates to the technical field of automatic measurement, in particular to a secondary voltage detection device and a secondary voltage detection method for a voltage transformer.

Background

When the secondary voltage of the voltage transformer on the transformer substation is abnormal, the abnormal fault of the voltage transformer or the transformer is indicated, if the abnormal fault cannot be found and processed in time, the normal operation of the voltage transformer can be influenced, and even the normal operation of the whole power grid can be influenced, so that a substation attendant is required to regularly measure the secondary voltage of the voltage transformer of the transformer substation and judge whether the data is normal. In the field measurement process, the following problems may exist: (1) the wiring error causes the measured data to be abnormal; (2) measurement data are abnormal due to the fact that measurement gears and measuring ranges of the measuring tool are selected wrongly; (3) the data analysis is not deep or the human record is wrong, so that the equipment abnormality cannot be found in time; (4) testing the short-circuit risk of the voltage transformer caused by wrong gear and range selection of instruments and meters; (5) personal risk of low voltage electrocution.

Disclosure of Invention

The embodiment of the invention provides a device and a method for detecting the secondary voltage of a voltage transformer, which can realize automatic detection of the secondary voltage of the voltage transformer and improve the detection accuracy and efficiency.

In a first aspect, an embodiment of the present invention provides a secondary voltage detection apparatus for a voltage transformer, including: the device comprises a main controller, an input switching module, a voltage division module, a full-wave rectification module and an analog-to-digital conversion module; the main controller is electrically connected with the input switching module, the input switching module is electrically connected with the voltage dividing module, the voltage dividing module is electrically connected with the full-wave rectification module, the full-wave rectification module is electrically connected with the analog-to-digital conversion module, and the analog-to-digital conversion module is electrically connected with the main controller;

the main controller is used for controlling the input switching module to switch the input voltage of each phase line of the acquisition cable; the voltage division module is used for carrying out voltage reduction processing on the input voltage of the phase line; the full-wave rectification module is used for converting the phase line input voltage subjected to voltage reduction processing by the voltage division module into direct-current voltage; the analog-to-digital conversion module is used for converting the direct-current voltage into a digital signal; and the main controller is also used for determining that the secondary voltage of the voltage transformer is abnormal when the digital signal is greater than a set threshold value.

Optionally, the input switching module includes at least two switching circuits; each switching circuit comprises a power supply end, an acquisition end, an output end and a control end;

the power end of each switching circuit is connected with an external power supply; the acquisition ends of the switching circuits are connected with the phase lines of the cable in a one-to-one correspondence manner; the output end of each switching circuit is electrically connected with the voltage division module; the control end of each switching circuit is electrically connected with the main controller; the main controller is used for controlling the switching circuits to be sequentially conducted with the voltage division module.

Optionally, the switching circuit further comprises a relay and a transistor;

the control end of the switching circuit is electrically connected with the control end of the transistor; a first end of a coil of the relay is electrically connected with the power supply end of the switching circuit, a second end of the coil of the relay is electrically connected with an input end of the transistor, and an output end of the transistor is grounded; the first end of the switch of the relay is electrically connected with the acquisition end of the switching circuit, and the second end of the switch of the relay is electrically connected with the output end of the switching circuit.

Optionally, the transistor includes an NPN transistor.

Optionally, the switching circuit further includes a first current limiting resistor, a second current limiting resistor, and a first diode;

the control end of the switching circuit is electrically connected with the control end of the transistor through the first current limiting resistor; the output end of the transistor is grounded through the second current-limiting resistor; the positive electrode of the first diode is electrically connected with the second end of the coil of the relay, and the negative electrode of the first diode is electrically connected with the first end of the coil of the relay.

Optionally, the voltage dividing module includes a transformer, a first capacitor, a second capacitor, and a divided voltage output end;

the first end of the high-voltage side of the transformer is electrically connected with the input switching module, and the second end of the high-voltage side of the transformer is electrically connected with the reference voltage end; the first end of the low-voltage side of the transformer is electrically connected with the first end of the first capacitor, and the second end of the low-voltage side of the transformer is grounded; the second end of the first capacitor and the first end of the second capacitor are both electrically connected with the divided voltage output end, and the second end of the second capacitor is grounded; the divided voltage output end is electrically connected with the full-wave rectification module.

Optionally, the full-wave rectification module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a second diode, a third diode, a first operational amplifier, and a second operational amplifier;

a first end of the first resistor and a first end of the fourth resistor are connected to a first node, a second end of the first resistor and a first end of the second resistor are connected to a second node, the second resistor and a first end of the third resistor are connected to a third node, and a second end of the third resistor and a second end of the fourth resistor are connected to a fourth node; a first end of the fifth resistor is electrically connected with the fourth node, and a second end of the fifth resistor is electrically connected with the analog-to-digital conversion module;

the inverting input end of the first operational amplifier and the cathode of the third diode are both electrically connected with the second node; the non-inverting input end of the first operational amplifier is grounded; the output end of the first operational amplifier and the anode of the third diode are both electrically connected with the cathode of the second diode; the anode of the second diode is electrically connected with the third node;

the inverting input end of the second operational amplifier is electrically connected with the fourth node, the non-inverting input end of the second operational amplifier is grounded, and the output end of the second operational amplifier is electrically connected with the second end of the fifth resistor.

Optionally, the device further comprises a display; the display is electrically connected with the main controller.

Optionally, a printer is also included; the printer is electrically connected with the main controller.

In a second aspect, an embodiment of the present invention further provides a method for detecting a secondary voltage of a voltage transformer, which is applied to any one of the above devices for detecting a secondary voltage of a voltage transformer, where the method for detecting a secondary voltage of a voltage transformer includes:

the input switching module is controlled to switch and collect input voltages of phase lines of the cable;

acquiring digital signals which are subjected to voltage reduction treatment by a voltage division module, converted from alternating current to direct current by a full-wave rectification module and converted by an analog-to-digital conversion module in sequence;

and when the digital signal is greater than a set threshold value, determining that the secondary voltage of the voltage transformer is abnormal.

The secondary voltage detection device of the voltage transformer comprises a main controller, an input switching module, a voltage division module, a full-wave rectification module and an analog-to-digital conversion module; the main controller is electrically connected with the input switching module, the input switching module is electrically connected with the voltage dividing module, the voltage dividing module is electrically connected with the full-wave rectification module, and the full-wave rectification module is electrically connected with the analog-to-digital conversion module; the main controller controls the input switching module to switch and collect input voltages of phase lines of a secondary voltage cable of the voltage transformer, the input voltages are subjected to voltage reduction processing through the voltage dividing module, alternating current voltage to direct current voltage processing is performed through the full-wave rectification module, the alternating current voltage to direct current voltage processing is performed after the alternating current voltage to direct current voltage processing is performed, the alternating current voltage is converted into digital signals through the analog-to-digital conversion module and then the digital signals are sent to the main controller, and when the digital signals. According to the voltage transformer secondary voltage detection device, the input switching module is controlled by the main controller to sequentially acquire input voltages of phase lines, the digital signals processed by the voltage dividing module, the full-wave rectification module and the analog-to-digital conversion module are calculated, and when the digital signals are larger than a set threshold value, the secondary voltage abnormity of the voltage transformer is determined, so that the automatic detection of the secondary voltage of the voltage transformer can be realized, the possible wiring errors, gear range errors, data errors, electric shock risks and the like caused by manual detection are avoided, and the detection efficiency, accuracy and safety are improved.

Drawings

Fig. 1 is a block diagram of a secondary voltage detection apparatus of a voltage transformer according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of an input switching module according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a voltage divider module according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a full-wave rectification module according to an embodiment of the present invention;

fig. 5 is a block diagram of a secondary voltage detection apparatus of another voltage transformer according to an embodiment of the present invention;

fig. 6 is a flowchart of a secondary voltage detection method for a voltage transformer according to a second embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

Fig. 1 is a block diagram of a secondary voltage detection device of a voltage transformer according to a first embodiment of the present invention. As shown in fig. 1, the secondary voltage detection device 10 of the voltage transformer includes a main controller 100, an input switching module 200, a voltage dividing module 300, a full-wave rectifying module 400 and an analog-to-digital conversion module 500; the main controller 100 is electrically connected with the input switching module 200, the input switching module 200 is electrically connected with the voltage dividing module 300, the voltage dividing module 300 is electrically connected with the full-wave rectifying module 400, the full-wave rectifying module 400 is electrically connected with the analog-to-digital conversion module 500, and the analog-to-digital conversion module 500 is electrically connected with the main controller 100; the main controller 100 is configured to control the input switching module 200 to switch the input voltages of the phase lines of the acquisition cable; the voltage dividing module 300 is used for performing voltage reduction processing on the phase line input voltage; the full-wave rectification module 400 is configured to convert the phase line input voltage after voltage reduction processing by the voltage division module into a direct-current voltage; the analog-to-digital conversion module 500 is configured to convert the dc voltage into a digital signal; the main controller 100 is further configured to determine that the secondary voltage of the voltage transformer is abnormal when the digital signal is greater than the set threshold.

The main controller 100 may be a core hardware module for controlling and allocating all hardware and executing general operations, such as a Central Processing Unit (CPU), and the main controller 100 may send a control switching signal to the input switching module 200 according to an internal preset program to control the input switching module 200 to sequentially collect input voltages of the phase lines.

The input switching module 200 may be an input switching circuit having a plurality of input terminals, each of which may be connected to each phase line of the cable of the secondary voltage of the voltage transformer through a stylus pen, and sequentially controls the input voltage, which is connected to each phase line from each input terminal, to be transmitted to the voltage dividing module 300 according to a control switching signal sent by the main controller 100.

The input voltage of each phase line collected by the input switching module 200 is generally 60-100V, and the voltage dividing module 300 performs voltage reduction processing on the input voltage of the phase line with a high voltage value to obtain the input voltage of the phase line with a low voltage value of 3-5V, and transmits the input voltage to the full-wave rectification module 400.

The full-wave rectification module 400 may be a circuit capable of converting an alternating current into a unidirectional current. The phase line input voltage after voltage reduction processing by the voltage dividing module 300 is an ac voltage, and the full-wave rectification module 400 can convert the ac phase line input voltage after voltage reduction processing by the voltage dividing module 300 into a dc phase line input voltage and transmit the dc phase line input voltage to the analog-to-digital conversion module 500.

The analog-to-digital conversion module 500, i.e. a/D converter, or ADC for short, generally refers to an electronic component for converting an analog signal into a digital signal. The input voltage of the dc phase line processed by the full-wave rectification module 400 is an analog input signal, and the analog-to-digital conversion module 500 can convert the analog input signal into a digital input signal that can be recognized by the main controller 100 and transmit the digital input signal to the main controller 100.

The main controller 100 finally performs operation processing on the received digital signals corresponding to each phase line, and may also automatically determine that the secondary voltage of the voltage transformer is abnormal when the operation processing result is greater than the internal program set threshold. Preferably, in the device 10 for detecting secondary voltage of a voltage transformer provided in the embodiment of the present invention, the main controller 100 may perform a pair-by-pair difference processing on the digital signals corresponding to the input voltages of the phase lines, and set a set deviation value, if a difference value of any pair of digital signals performing the pair-by-pair difference is greater than the set deviation value, it indicates that a voltage on at least one phase line is abnormal on a cable of the secondary voltage of the voltage transformer, and the main controller 100 may automatically determine that the secondary voltage of the voltage transformer is abnormal, so as to prompt a worker to perform an inspection and maintenance in time.

According to the voltage transformer secondary voltage detection device, the input switching module is controlled by the main controller to sequentially acquire input voltages of phase lines, the digital signals processed by the voltage dividing module, the full-wave rectification module and the analog-to-digital conversion module are calculated, and when the digital signals are larger than a set threshold value, the secondary voltage abnormity of the voltage transformer is determined, so that the automatic detection of the secondary voltage of the voltage transformer can be realized, the possible wiring errors, gear range errors, data errors, electric shock risks and the like caused by manual detection are avoided, and the detection efficiency, accuracy and safety are improved.

Fig. 2 is a schematic structural diagram of an input switching module according to an embodiment of the present invention. Alternatively, as shown in fig. 2, the input switching module 200 may include at least two switching circuits (two switching circuits are exemplarily marked in the figure); each switching circuit comprises a power supply end 210, an acquisition end 220, an output end 230 and a control end 240; the power end 210 of each switching circuit is connected with an external power supply 600; the acquisition end 220 (the first terminal M1 and the second terminal M2) of each switching circuit is connected with each phase line (a phase line and B phase line) of the cable in a one-to-one correspondence manner; the output end 230 of each switching circuit is electrically connected and electrically connected with the voltage dividing module 300; the control terminals 240(ZJL1 and ZJL2) of the respective switching circuits are electrically connected to the main controller 100; the main controller 100 is used for controlling each switching circuit to be sequentially conducted with the voltage dividing module 300.

The input switching module 200 provided in the embodiment of the present invention may select the number of switching circuits according to the actual situation of the secondary voltage detection field of the voltage transformer, and fig. 2 exemplarily indicates two switching circuits. The power terminals 210 of the switching circuit are each electrically connected to an external power source 600 for supplying power to the various electrical components in the switching circuit. The collecting terminal 220 (the first terminal M1 and the second terminal M2) of the switching circuit may be connected to each phase line (phase line a and phase line B) of the secondary voltage cable by using a stylus pen for collecting input voltage on each phase line. The output ends 230 of the switching circuits are electrically connected to the voltage dividing module 300, and are configured to transmit the input voltage of each phase line of the collecting end 220 (the first terminal M1 and the second terminal M2) to the voltage dividing module 300 when each switching circuit is turned on. The control terminals 240(ZJL1 and ZJL2) of the switching circuits are electrically connected to the main controller 100, and are configured to receive control switching signals transmitted from the main controller 100 and control the on/off of the switching circuits. It should be noted that, in the secondary voltage detection device 10 of the voltage transformer according to the embodiment of the present invention, the main controller 100 only controls one switching circuit to be turned on at a time, and only transmits the corresponding phase line input voltage collected by the collecting terminal 220 (the first terminal M1 and the second terminal M2) of the one switching circuit to the voltage dividing module 300.

Optionally, with continued reference to fig. 2, the switching circuit may further include a relay 250 (exemplarily labeled first relay K1 and second relay K2 in the figure) and a transistor 260 (exemplarily labeled first transistor Q1 and second transistor Q2 in the figure); the control terminals 240(ZJL1 and ZJL2) of the switching circuit are electrically connected to the control terminals of the transistors 260 (the first transistor Q1 and the second transistor Q2); a first end of a coil of the relay 250 (the first relay K1 and the second relay K2) is electrically connected to the power supply terminal 210 of the switching circuit, a second end of the coil of the relay 250 (the first relay K1 and the second relay K2) is electrically connected to an input end of the transistor 260 (the first transistor Q1 and the second transistor Q2), and an output end of the transistor 260 (the first transistor Q1 and the second transistor Q2) is grounded; a first terminal of the switch of the relay 250 (the first relay K1 and the second relay K2) is electrically connected to the sampling terminal 220 (the first terminal M1 and the second terminal M2) of the switching circuit, and a second terminal of the switch of the relay 250 (the first relay K1 and the second relay K2) is electrically connected to the output terminal 230 of the switching circuit.

The main controller 100 sends a control switching signal to the input switching module 200, and the control terminals 240(ZJL1 and ZJL2) of the switching circuits receive the control switching signal, and control the on/off of the transistors 260 (the first transistor Q1 and the second transistor Q2), and further control the power-on/off of the coils of the relay 250 (the first relay K1 and the second relay K2), and further control the on/off of the switches of the relay 250 (the first relay K1 and the second relay K2), and further control the phase line input voltage collected by the collecting terminal 220 (the first terminal M1 and the second terminal M2) of the switching circuit to be transmitted to the voltage dividing module 300.

Alternatively, as shown with continued reference to fig. 2, the transistor 260 (the first transistor Q1 and the second transistor Q2) may comprise an NPN transistor.

The bases of the transistors 260 (the first transistor Q1 and the second transistor Q2) are electrically connected to the control terminals 240(ZJL1 and ZJL2) of the switching circuit; the collectors of the transistors 260 (the first transistor Q1 and the second transistor Q2) are electrically connected to the second ends of the coils of the relays 250 (the first relay K1 and the second relay K2), and the emitters of the transistors 260 (the first transistor Q1 and the second transistor Q2) are grounded.

Optionally, as shown in fig. 2, the switching circuit may further include a first current limiting resistor R1 '(R11' and R12 '), a second current limiting resistor R2' (R21 'and R22'), and a first diode D1(D11 and D12); the control terminals 240(ZJL1 and ZJL2) of the switching circuit are electrically connected to the control terminal of the transistor 260 (the first transistor Q1 and the second transistor Q2) through a first current limiting resistor R1 ' (R11 ' and R12 '); the output terminal of the transistor 260 (the first transistor Q1 and the second transistor Q2) is grounded through a second current limiting resistor R2 ' (R21 ' and R22 '); the positive electrode of the first diode D1(D11 and D12) is electrically connected to the second end of the coil of the relay 250 (the first relay K1 and the second relay K2), and the negative electrode of the first diode D1(D11 and D12) is electrically connected to the first end of the coil 250 of the relay (the first relay K1 and the second relay K2).

The first current limiting resistor R1 '(R11' and R12 ') and the second current limiting resistor R2' (R21 'and R22') both provide current limiting for the transistor 260 (the first transistor Q1 and the second transistor Q2); the first diode D1(D11 and D12) prevents the relay 250 (the first relay K1 and the second relay K2) from being connected reversely.

Fig. 3 is a schematic structural diagram of a voltage divider module according to an embodiment of the present invention. Alternatively, referring to fig. 3, the voltage dividing module 300 may include a transformer T1, a first capacitor C1, a second capacitor C2, and a divided voltage output terminal U1; a first end of the high-voltage side of the transformer T1 is electrically connected with the input switching module 200, and a second end of the high-voltage side of the transformer is electrically connected with the reference voltage terminal N600; a first end of the low-voltage side of the transformer T1 is electrically connected with a first end of the first capacitor C1, and a second end of the low-voltage side of the transformer T1 is grounded; the second end of the first capacitor C1 and the first end of the second capacitor C2 are both electrically connected with the divided voltage output terminal U1, and the second end of the second capacitor C2 is grounded; the divided voltage output terminal U1 is electrically connected to the full-wave rectification module 400.

The transformer T1 is used to step down the high-side phase input voltage. The first capacitor C1 and the second capacitor C2 constitute a capacitor voltage dividing circuit, which is used for further performing voltage reduction processing on the phase line input voltage subjected to voltage reduction processing by the transformer T1. The input voltage of the phase line input by the input switching module 200 is generally about 60-100V, and is reduced to 3-5V through the voltage dividing module 300 for output.

Fig. 4 is a schematic structural diagram of a full-wave rectification module according to an embodiment of the present invention. Alternatively, referring to fig. 4, the full-wave rectification module 400 may include a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second diode D2, a third diode D3, a first operational amplifier 410, and a second operational amplifier 420; a first end of the first resistor R1 and a first end of the fourth resistor R4 are connected to the first node P1, a second end of the first resistor R1 and a first end of the second resistor R2 are connected to the second node P2, first ends of the second resistor R2 and the third resistor R3 are connected to the third node P3, and a second end of the third resistor R3 and a second end of the fourth resistor R4 are connected to the fourth node P4; a first end of the fifth resistor R5 is electrically connected to the fourth node P4, and a second end of the fifth resistor R5 is electrically connected to the analog-to-digital conversion module 500; the inverting input terminal of the first operational amplifier 410 and the cathode of the third diode D3 are both electrically connected to the second node P2; the non-inverting input of the first operational amplifier 410 is grounded; the output end of the first operational amplifier 410 and the anode of the third diode D3 are both electrically connected to the cathode of the second diode D2; the anode of the second diode D2 is electrically connected to the third node P3; the inverting input terminal of the second operational amplifier 420 is electrically connected to the fourth node P4, the non-inverting input terminal of the second operational amplifier 420 is grounded, and the output terminal of the second operational amplifier 420 is electrically connected to the second terminal of the fifth resistor R5.

The full-wave rectification module 400 receives the input voltage of each phase line, which is transmitted by the voltage dividing module 300 and is subjected to voltage reduction processing, through the first node P1, converts the input voltage of the phase line into a direct current voltage, and transmits the converted direct current voltage to the analog-to-digital conversion module 500 through the second end of the fifth resistor R5. Preferably, the first resistor R1, the second resistor R2, and the third resistor R3 have a resistance value of R, and the fourth resistor R4 and the fifth resistor R5 have a resistance value of 2R.

When the first node P1 receives the phase line input voltage V_inWhen the voltage V at the first end of the second resistor R2, i.e., the second node P2, is positive, the second diode D2 is turned on, the third diode D3 is turned off, and the first end of the second resistor R2 is connected to the second node P2 according to the virtual short break principle of the operational amplifier_P20, the voltage V at the second terminal of the third resistor R3, i.e., the fourth node P4_P4Is 0, and further according to the circuit principle, the voltage V at the second terminal of the second resistor R2, i.e. the third resistor R3, the third node P3_P3Can be calculated by the following formula one:

calculate to obtain V_P3＝-V_inAnd further the second terminal of the fifth resistor R5, i.e. the output voltage V of the full-wave rectification module 400_outCan be calculated by the following formula two:

calculate to obtain V_out＝V_inThat is, in the full-wave rectification module 400, when the input voltage is positive, the output voltage is also positive.

When the first node P1 receives the phase line input voltage V_inWhen negative, the second diode D2 is turned off, the third diode D3 is turned on, and the voltage V at the first end of the second resistor R2, i.e., the second node P2, is determined according to the virtual short break principle of the operational amplifier_P20, the voltage V at the second terminal of the third resistor R3, i.e., the fourth node P4_P40, since the second diode D2 is turned off, no current flows through the second resistor R2 and the third resistor R3, and no voltage is applied, which is equivalent to an open circuit, and the second terminal of the fifth resistor R5, i.e. the output voltage V of the full-wave rectifier module 400, is based on the circuit principle_out' can be calculated by the following formula three:

calculate to obtain V_out’＝-V_inIn the full-wave rectifier module 400, when the input voltage is negative, the output voltage is positive. The ac voltage of each phase line can be converted into dc voltage by the full-wave rectification module 400.

Fig. 5 is a block diagram of a secondary voltage detection apparatus of another voltage transformer according to an embodiment of the present invention. Optionally, referring to fig. 5, the voltage transformer secondary voltage detection apparatus 10 may further include a display 700; the display 700 is electrically connected to the main controller 100. The display 700 may be a display means such as a CRT, LCD, and LCD screen, etc. which displays certain electronic files on a screen through a specific transmission device and reflects the files to human eyes. The display 700 adopted by the embodiment of the invention is used for displaying the secondary voltage value of the voltage transformer which is measured each time and the judgment result, so that the working personnel can conveniently and visually know the detection process clearly and constantly observe whether the data is in a reasonable range.

Optionally, as shown in fig. 5, the voltage transformer secondary voltage detection apparatus 10 may further include a printer 800; the printer 800 is electrically connected to the main controller 100. The printer 800 can automatically output a voltage value and a judgment result to generate a report when measuring the secondary voltage of the voltage transformer every time, and the report is printed, so that the report is convenient for workers to store, and the counterfeiting of the measured data can be effectively avoided.

The secondary voltage detection device of the voltage transformer provided by the embodiment of the invention comprises a main controller, an input switching module, a voltage division module, a full-wave rectification module and an analog-to-digital conversion module; the main controller is electrically connected with the input switching module, the input switching module is electrically connected with the voltage dividing module, the voltage dividing module is electrically connected with the full-wave rectification module, and the full-wave rectification module is electrically connected with the analog-to-digital conversion module; the main controller controls the input switching module to switch and collect input voltages of phase lines of a voltage transformer secondary voltage cable, voltage reduction processing is carried out through the voltage dividing module, processing of converting alternating current voltage into direct current voltage is carried out through the full-wave rectification module, the alternating current voltage is converted into digital signals through the analog-to-digital conversion module and then sent to the main controller, when the digital signals are larger than a set threshold value, the voltage transformer secondary voltage is determined to be abnormal, automatic detection of the voltage transformer secondary voltage can be achieved, wiring errors which may occur in manual detection are avoided, gear range errors, data errors, electric shock risks and the like, and therefore detection efficiency, accuracy and safety are improved. In addition, the secondary voltage detection device of the voltage transformer provided by the embodiment of the invention also comprises a display and a printer, and can display the output voltage value and the judgment result or generate a report and print the report, so that a worker can conveniently observe whether the data is in a reasonable range at any time, and the counterfeiting of the measured data is avoided.

Example two

On the basis of the foregoing embodiment, a second embodiment of the present invention provides a method for detecting a secondary voltage of a voltage transformer, which is suitable for the device 10 for detecting a secondary voltage of a voltage transformer described in the first embodiment. Fig. 6 is a flowchart of a secondary voltage detection method for a voltage transformer according to a second embodiment of the present invention. As shown in fig. 6, the secondary voltage detection method of the voltage transformer includes:

and S110, controlling the input switching module to switch and collect input voltages of phase lines of the cable.

The input switching module can be an input switching circuit with a plurality of input terminals, each input terminal can be connected to each phase line of the cable of the secondary voltage of the voltage transformer through a gauge pen, and the input voltage accessed to each phase line from each input terminal is sequentially controlled to be transmitted to the voltage dividing module according to a control switching signal sent by the main controller.

And S120, acquiring digital signals which are subjected to voltage reduction treatment by the voltage division module, converted into alternating current and direct current by the full-wave rectification module and converted into analog-to-digital conversion modules in sequence.

The input voltage of each phase line is subjected to voltage reduction treatment by a voltage division module, is subjected to alternating current voltage to direct current voltage treatment by a full-wave rectification module, is converted into a digital signal by an analog-to-digital conversion module and then is sent to a main controller,

and S130, when the digital signal is larger than the set threshold value, determining that the secondary voltage of the voltage transformer is abnormal.

The main controller can carry out difference processing on every two digital signals corresponding to input voltages of all phase lines, a set deviation value is set, if the difference value of any pair of digital signals which are subjected to difference processing is larger than the set deviation value, the voltage abnormality of at least one phase line on a cable of secondary voltage of the voltage transformer is indicated, the secondary voltage abnormality of the voltage transformer can be automatically determined, and then workers are timely reminded to carry out inspection and maintenance.

In the embodiment of the invention, the input switching module is controlled by the main controller to switch and collect the input voltages of the phase lines of the secondary voltage cable of the voltage transformer, the voltage division module is used for carrying out voltage reduction processing, the full-wave rectification module is used for carrying out alternating current voltage to direct current voltage processing, the analog-to-digital conversion module is used for converting the alternating current voltage into a digital signal and then transmitting the digital signal to the main controller, and when the digital signal is greater than a set threshold value, the main controller determines that the secondary voltage of the voltage transformer is abnormal, so that the automatic detection of the secondary voltage of the voltage transformer can be realized, the wiring error, the gear range error, the data error, the electric shock hazard and the.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.