KR20180054330A - Test device for Surge protective device - Google Patents

Abstract

The present invention relates to a test device for a power surge protective device capable of reliably inspecting a deterioration state of a surge protector used for a power source. The test device for testing a deterioration state of a varistor built in a power surge protective device by applying direct current power to the power surge protective device comprises: a power supply unit; a measurement voltage applying unit; a measurement path setting unit; a leaking current measuring unit; a measurement voltage measuring unit; a signal adjusting unit; an A/D converter unit; a state determining unit; a user interface unit; and a control unit.

Description

{Test device for Surge protective device}

The present invention relates to a power surge protector inspecting apparatus capable of reliably inspecting a deterioration state of a surge protector used for a power source.

In general, surge protectors (SPDs) are used to protect electrical equipment from overvoltages caused by lightning or power system failures. These surge protectors are divided into power supply and signal use depending on the application.

On the other hand, the surge suppressor for power supply is installed on the power supply line to protect the power equipment from the surge voltage generated from the power source. When the surge voltage is applied, it changes from high impedance momentarily to low impedance, It has a built-in varistor to shut off the surge voltage.

That is, when an overvoltage is instantaneously applied along the power supply line, the varistor instantaneously operates to shut off the overvoltage to protect the power equipment. However, when varistors are repeatedly exposed to overvoltage, deterioration proceeds and burnout occurs. As a result, the impedance is lowered, which may cause a short circuit or fire.

Therefore, in order to prevent a short-circuit accident or fire, a surge protector is used to detect the deterioration state of the varistor built in the surge protector and inspect the state of the surge protector.

Such a surge protector test apparatus is configured in various forms according to the inspection method. Among them, it is known that the inspection method for determining the deterioration state by measuring the leakage current of the varistor is the most reliable type.

A conventional surge protector testing apparatus to which the lap wire current measuring method is applied includes a DC power supply, a voltage divider circuit connected to both ends of the DC power supply, a shunt resistor having one terminal connected to the second terminal of the DC power supply, and a plurality of switches A relay module for controlling the relay module and the DC power supply and the relay module for connecting the first terminal of the DC power supply and the other terminal of the shunt resistor to the two terminals of the surge protector according to the LN, LG, and NG modes of the surge protector, And a microprocessor that calculates the leakage current of the varistor of the surge protector through the current flowing in the shunt resistor at the 2 voltage to determine the deterioration state.

However, due to the use of a power source externally applied through a DC power supply, it is difficult to use it in a field where power supply is not smooth.

In addition, since the varistor leakage current of the surge protector is calculated through the current flowing through the shunt resistor at the first voltage and the second voltage, there is a problem that the deterioration state can not be accurately discriminated when the degradation of the varistor proceeds.

In the surge protector, there is a structure in which a gas discharge tube (GDT) having a relatively large discharge capacity is incorporated instead of a part of the varistors among a plurality of varistors. In such a structure, the voltage of the varistor can not be measured, .

Further, when a circuit element such as a diode is connected in series or in parallel with a varistor in a surge protector, there is a problem that a measurement error occurs due to the diode or measurement is impossible.

Korean Registered Patent No. 10-1413561, Apr. 14, 2014.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a power supply device capable of being conveniently used in a place where power supply is not smooth, accurately checking the deterioration state of a varistor, The present invention also provides a surge protector for a power supply that can eliminate a measurement error caused by a surge protector.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood from the following description.

According to an aspect of the present invention, there is provided an apparatus for inspecting a surge protector for a power supply, the apparatus comprising: a surge protector for inspecting a deterioration state of a varistor built in the surge protector, A power supply unit for supplying power; A measurement voltage application unit configured to receive the operation power from the power supply unit to generate a variable measurement voltage and apply the measurement voltage to the surge protector; A measurement path setting unit for setting a measurement path for measuring a leakage current and a voltage of the varistor corresponding to a protection mode of the surge protector when the measured voltage is applied to the surge protector; A leakage current measuring unit measuring a leakage current of the varistor corresponding to the measurement path and outputting a first signal corresponding to the leakage current; A measuring voltage measuring unit measuring the measured voltage applied to the surge protector and outputting a second signal corresponding to the measured voltage; A signal adjusting unit for filtering and amplifying the first signal and the second signal, respectively; An A / D converter for converting the filtered and amplified first signal and the second signal into a first digital signal and a second digital signal, respectively; A state determiner for determining a deterioration state of the varistor by calculating a voltage and a nonlinear coefficient of the varistor from the first digital signal and the second digital signal; A user interface unit having an output means for displaying the measurement path, the measurement voltage, discrimination information of the surge protector and related information, and input means for receiving a user's operation signal; And a controller for controlling each of the above components.

The surge protector for power surge inspecting apparatus according to the present invention can be used conveniently in a place where the power supply is not smooth, can accurately determine the deterioration state of the varistor, can check the presence or absence of the gas discharge tube, And also the identification information and the related information of the surge protector are separately stored and managed. Thus, it is possible to reliably discriminate whether the surge protector has a wide variety of manufacturers.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Fig. 2 is a circuit configuration diagram of the polarity converting unit and the measurement path setting unit of Fig. 1; Fig.
3 is a circuit diagram of a single-phase surge protector for power supply.
4 is a circuit diagram of a three-phase surge protector for power supply.
5 is a circuit diagram showing a configuration in which a leakage current of a varistor is changed in accordance with polarity conversion by the polarity converting unit of FIG.

A surge protector connected to a power supply line for inspecting a deterioration state of a built-in varistor by checking a state of a surge protector that prevents an overvoltage from being damaged due to overvoltage by interrupting an overvoltage applied along a power supply line, To an inspection apparatus.

Particularly, the surge protector for power supply according to the present invention can be conveniently used in a place where the power supply is not smooth, can accurately determine the deterioration state of the varistor, can check whether the gas discharge tube is included, It is possible to solve the measurement error caused by the device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a surge protector for a power supply according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1, the surge protector for power supply according to a preferred embodiment of the present invention includes a power supply unit 10, a measurement voltage application unit 20, a measurement path setting unit 30, a leakage current measurement unit 40, A measurement voltage measuring unit 50, a signal adjusting unit 60, an A / D converter unit 70, a state determining unit 80, a user interface unit 90, and a control unit 100.

First, the power supply unit 10 supplies operation power using the power of the battery so that the power supply unit 10 can be used in a place where power supply is not smooth.

The power supply unit 10 includes a battery 11 having a predetermined capacity and a charge and discharge circuit 12 that receives external power and charges the battery 11 and outputs power of the charged battery 11 do.

Next, the measurement voltage application unit 20 generates a measurement voltage using the operation power supplied from the power supply unit 10, and applies the measured voltage to the surge protector 200. FIG.

At this time, the measurement voltage applying unit 20 applies the measured voltage to the surge protector 200 in a variable form. That is, it is possible to output the measured voltage up to 2 kV and apply the voltage to the surge protector while gradually increasing the voltage in the form of a ramp waveform until the leakage current of the varistor reaches about 3 mA.

Next, the measurement path setting unit 30 is configured to set a measurement path for measuring the leakage current of the varistor corresponding to the protection mode of the surge protector 200.

That is, since the protection mode of the surge protector 200 is divided into a single phase and a three-phase according to the type of the power supply line, the measurement path setting unit 30 may be configured to measure the leakage current of the varistor according to the protection mode of the surge protector To set the measurement path.

At this time, the measurement path setting unit 30 uses a plurality of high voltage relays as shown in FIG. 2 (b), and the high voltage relay is connected to the output terminal of the measurement voltage application unit 20 to which the measurement voltage is applied, Respectively.

3, when the surge protector 200 is single-phase, the measurement path setting unit 30 can set a measurement path between L1-PE, N-PE, and L1-N, Similarly, when the surge protector 200 has three phases, the measurement path can be set between L1-N, L2-N, L3-N, and N-PE.

Next, the leakage current measuring unit 40 measures the leakage current of the varistor connected along the measurement path set by the measurement path setting unit 30 when the measurement voltage is applied to the surge protector.

At this time, the leakage current measuring unit 40 measures the leakage current of the varistor and then outputs a first signal of the analog signal type corresponding to the magnitude of the measured leakage current of the varistor.

On the other hand, the leakage current measuring unit 40 measures the leakage current of the varistor using a high-precision shunt, a current sensor, and the like, and has a measurement range of several tens of microamperes to several mA.

Next, the measurement voltage measuring unit 50 measures a measurement voltage applied to the surge protector by the measurement voltage application unit 20. [

That is, the measurement voltage measuring unit 50 is for measuring a measurement voltage applied to the surge protector when a leakage current flows through the varistor. The measurement voltage measuring unit 50 measures the measured voltage, And outputs a signal.

At this time, the measuring voltage measuring unit 50 uses a resistance voltage divider to measure a high voltage and a resistance voltage divider to measure a voltage of several kV.

Next, the signal adjusting unit 60 receives the first signal and the second signal according to the leakage current and the measured voltage of the varistor measured and output by the leakage current measuring unit 40 and the measured voltage measuring unit 50, Is removed and amplified.

That is, the signal adjustment unit 60 receives the first signal and the second signal from the leakage current measurement unit 40 and the measurement voltage measurement unit 50, filters the noise through the low-frequency band filter, To increase the measurement accuracy of the leakage current and the measured voltage of the varistor.

Next, the A / D converter unit 70 receives the first signal and the second signal that are filtered and amplified by the signal adjusting unit 60, respectively, and converts the first and second signals into a first digital signal and a second digital signal.

That is, the A / D converter unit 70 converts the first signal and the second signal into a digital signal format so that it can be processed by the state determination unit 80, which will be described later.

Next, the state determination unit 80 determines a deterioration state of the varistor based on the first digital signal and the second digital signal output from the A / D converter unit 70. [

That is, the state judging unit 80 calculates the voltage of the varistor by using the first digital signal and the second digital signal, judges whether the voltage of the calculated varistor has fluctuated by 10% or more from the reference voltage of the corresponding varistor, The state is finally determined.

On the other hand, in order to improve the reliability and accuracy in determining the deterioration state of the varistor, the state determiner 80 calculates the nonlinear coefficient (alpha) of the following equation (1) State.

&Quot; (1) "

α is a nonlinear coefficient, I1 is 0.1 mA, I2 is 1.0 mA, V1 is a varistor voltage when a current flows and V2 is a varistor voltage when a current of 1.0 mA flows.

That is, the nonlinear coefficient indicates the ratio of the varistor voltage and the varistor current when a current of 0.1 mA is applied to the varistor, and the degradation state of the varistor can be determined according to the magnitude of α.

The state determination unit 80 has a function of determining from the first digital signal that is the leakage current of the varistor that the gas discharge tube (GDT) is connected to the measurement path instead of the varistor.

That is, in the case of the gas discharge tube, the electrical characteristic is different from that of the varistor, and an electrical characteristic that the leakage current abruptly increases at a specific voltage appears.

Accordingly, when the electrical characteristics of the gas discharge tube as described above appear in the leakage current as the first digital signal, it is determined that the gas discharge tube is connected to the measurement path instead of the varistor.

The user interface unit 90 includes an input device and an output device. The user interface 90 inputs a product information of a surge protector to be inspected, and outputs a measurement progress and a measurement result.

That is, the user interface unit 90 is provided with a screen, a light emitting diode, and the like so that the measurement path, the measured voltage, and the result of discriminating the varistor can be outputted as letters, numbers, and graphs, and the user inputs product information of the surge protector An operation dial, an operation button, and the like are provided so that the device can be turned on and off.

The control unit includes the measurement voltage application unit 20, the measurement path setting unit 30, the leakage current measurement unit 40, the measurement voltage measurement unit 50, the signal adjustment unit 60, and the A / The control unit 70 controls the state discrimination unit 80 and the user interface unit 90 so that they can operate mutually.

1, the polarity converting unit 110 may be further included between the measurement voltage applying unit 20 and the measurement path setting unit 30, as shown in FIG. 1, have.

The polarity converting unit 110 is configured to convert the polarity of the measurement power applied to the surge protector 200 by the measurement voltage applying unit 20. [

That is, in order to more accurately measure the leakage current of the varistor, the polarity converting unit 110 converts the polarity of the measurement voltage applied from the output terminal of the measurement voltage applying unit 20 to the surge protector 200 from positive to negative, Polarity to positive polarity.

The reason for converting the polarity of the measured voltage is that, as shown in FIG. 5, since a diode, a resistor, and a light emitting diode are connected to a normal surge protector 200 in addition to a power supply state and a fuse varistor, only the leakage current of the varistor It is difficult to measure.

Therefore, when the leakage current of the varistor flows through the leakage current of the varistor more than the leakage current of the varistor, the polarity of the measured voltage is negatively polarized through the polarity converting part 110 Thereby eliminating the influence of current components flowing to circuit elements other than the varistor.

At this time, the polarity converting unit 110 is configured as a high voltage relay so as to withstand the measurement power of high voltage as shown in FIG.

In addition, the surge protector for power supply according to the preferred embodiment of the present invention may further include a data storage unit 120 as shown in FIG.

The data storage unit 120 stores and manages the identification information of the surge protector, previous identification information of the surge protector, specification information of the surge protector, and the like. The specification information of the surge protector includes information such as model name, manufacturer, MCOV voltage, product type, varistor voltage, protection mode, and protection device.

Therefore, the state determination unit 80 can determine the deterioration state of the surge protector 200 based on the specification information of the surge protector 200 stored in the data storage unit 120, store the determination information by date, And can also be used as reference data for determining whether the surge protector 200 deteriorates through the stored discrimination information.

At this time, the data storage unit 120 may include an internal memory built in the device or an external memory connected to a connection terminal separately provided to the device, if necessary.

The above-described embodiments are merely illustrative, and various modifications may be made by those skilled in the art without departing from the scope of the present invention.

Therefore, the true technical protection scope of the present invention should include not only the above embodiments but also various other modified embodiments according to the technical idea of the invention described in the following claims.

10: Power supply
20: Measurement voltage application unit
30: Measurement path setting unit
40: Leakage current measuring unit
50: Measurement voltage measuring unit
60:
70: A / D converter section
80:
90: User interface section
100:
110: polarity conversion section
120: Data storage unit
200: Surge protector

Claims (4)

A DC power source is applied to a power supply for a surge suppressor to inspect the deterioration state of a varistor built in the surge protector,
A power supply unit for supplying operating power using the power of the battery;
A measurement voltage application unit configured to receive the operation power from the power supply unit to generate a variable measurement voltage and apply the measurement voltage to the surge protector;
A measurement path setting unit for setting a measurement path for measuring a leakage current and a voltage of the varistor corresponding to a protection mode of the surge protector when the measured voltage is applied to the surge protector;
A leakage current measuring unit measuring a leakage current of the varistor corresponding to the measurement path and outputting a first signal corresponding to the leakage current;
A measuring voltage measuring unit measuring the measured voltage applied to the surge protector and outputting a second signal corresponding to the measured voltage;
A signal adjusting unit for filtering and amplifying the first signal and the second signal, respectively;
An A / D converter for converting the filtered and amplified first signal and the second signal into a first digital signal and a second digital signal, respectively;
A state determiner for determining a deterioration state of the varistor by calculating a voltage and a nonlinear coefficient of the varistor from the first digital signal and the second digital signal;
A user interface unit having an output means for displaying the measurement path, the measurement voltage, discrimination information of the surge protector and related information, and input means for receiving a user's operation signal; And
And a control unit for controlling each of the above components. The method according to claim 1,
And a polarity converting unit for converting a polarity of the measured power source applied to the surge protector by the DC power applying unit into a positive polarity or a negative polarity,
The state determiner
Wherein the deterioration state of the varistor is discriminated by comparing the first digital signal which is the leakage current of the varistor according to the polarity in which the polarity is not converted and the polarity in which the polarity is changed by the polarity converting unit, Inspection device. The method according to claim 1,
And a data storage unit for storing and managing identification information of the surge protector and related information of the surge protector. The method according to claim 1,
The state determiner
And determines whether the gas discharge tube is connected to the measurement path from the first digital signal that is the leakage current of the varistor.

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