KR20230015190A - Inspection apparatus for power metering equipment and method - Google Patents

Abstract

An inspection apparatus for power metering equipment in the present invention may include: a sensing module that measures the voltage and current of a test MOF terminal; a three-phase four-wire power calculation part that calculates a three-phase four-wire power consumption value from the measured values of voltage and current of the MOF terminal; a three-phase three-wire power calculation part that calculates the three-phase three-wire power consumption value from measured values of voltage and current of the MOF terminal; and an MOF inspection part that compares the power consumption values calculated by the three-phase four-wire power calculation part and the three-phase three-wire power calculation part to determine the normality of a test MOF.

Description

Apparatus and method for checking power metering equipment {INSPECTION APPARATUS FOR POWER METERING EQUIPMENT AND METHOD}

The present invention relates to an inspection device and method for power metering devices capable of collectively inspecting CTs, PTs, MOFs, and power meters (power meters) for power improvement devices including power metering devices and MOFs.

Non-technical losses for electric power companies include failure to charge due to omission of sales customers, unauthorized use of power, insufficient metering caused by secular change in power metering facilities (CT, PT, MOF, power meter), Non-technical loss refers to measurement loss caused by a worker's mistake in wiring for weighing or a defect in equipment manufacturing.

Among the non-technical losses, it is not easy to improve those arising from the non-transparent fee collection process and challenges due to complex factors stemming from the social and cultural environment. However, there are many ways to minimize losses caused by equipment defects, failures, and secular changes in auxiliary devices used for power metering (current transformers, transformers, terminal blocks, etc.) and watt-hour meters. As a general management method for power metering devices, it is used by determining the lifespan. In our case, according to the type of watt-hour meter, it is intended to be used only for a specified period based on sub-related standards such as the Metering Act.

On the other hand, the MOF, which is a transformer for power metering (also referred to as an instrument transformer), has no expiration date, so it is used unless defects are visible to the naked eye or it does not cause a major problem in use. Therefore, companies that sell electricity reduce non-technical losses through inspections at regular intervals. However, there is a limit to inspecting all customers, so the inspection target is selectively determined. In general, the target is a high-pressure customer with a lot of usage.

1a and 1b are photographs showing defect types according to internal mixing of MOFs.

2a and 2b are photographs showing defect types according to internal mixing of MOFs.

3a and 3b are photographs showing defect types according to internal mixing of MOFs.

4 is a single-line diagram of a domestic extra-high voltage power receiving facility.

In the case of KEPCO, regular inspection is performed once every three years, but the power metering device is inspected through direct management or outsourcing to a specialized company. The high-voltage customer's facilities are as shown in FIG. 2, and the inspection method checks whether the watt-hour meter and accessories are normal with separate test equipment. In order to check whether the watt-hour meter maintains an error within the legal tolerance range, a portable watt-hour meter standard tester with higher precision than the watt-hour meter to be tested is used. MOF, an accessory device, checks whether the primary side (high voltage 22.9KV/13.2KV) and secondary side (190V/110V low voltage) ratio of voltage and current is maintained through a dedicated tester.

Looking at the inspection status, the annual average number of inspections for electricity metering values of high-voltage customers is about 70,000. The error check of the watt-hour meter digests all of the annual inspection volume, but the MOF error is inspected only for less than 10% of the annual volume (about 7,000 households).

Unlike watt-hour meters, the reason why only some customers select and check MOF is because of limited time and cost. This is because the inspector must be qualified in the relevant field, so the number of inspectors is limited and the expenses that can be spent are fixed. In the case of inspecting only the watt-hour meter, a team of 2 is organized and only a standard for the error test of the watt-hour meter is required. However, in the case of testing the error of the watt-hour meter and the MOF simultaneously, a team of 3 is required and there must be an additional person and a dedicated test device for the error test of the MOF.

The number of MOF inspections by high-voltage customers is about 7,000. Since there are 210,000 high-pressure customers, the inspection cycle for each customer is once every 30 years. Considering that the lifespan of a transformer is usually 20 years, considering the electrical and mechanical characteristics of the transformer, normal management of the MOF is realistically difficult. In the end, this means that the MOF does not function normally, leading to metering loss. In fact, through regular tests, the amount of agreement due to MOF abnormalities reaches 1 billion won per year. Since the method of the agreement is also from the point of finding the abnormality to the normalization, it is estimated that the actual loss amount is occurring on a much larger scale than this.

In the case of the watt-hour meter error test, you only need to connect the voltage sensor and current sensor at the secondary side, low voltage (190V/110V), and attach a device that collects the active power pulse of the meter to compare the watt-hour meter error.

However, in the MOF conversion ratio error test, the current flowing in the primary side (22.9kV/13.2kV) extra-high voltage and the secondary side (190V/110V) low voltage circuit must be measured simultaneously. Access to live wires is unavoidable, and the inspection environment for power receiving facilities is not standardized, so you must always be careful about safety accidents caused by electric shock. In fact, there is a case where an accident occurred during the inspection process, and it is difficult to fundamentally prevent it with conventional technology.

Republic of Korea Registration No. 10-1801611

An object of the present invention is to provide a checking method and apparatus for a power metering device capable of economically and efficiently checking an MOF.

An inspection apparatus for a power metering device according to an aspect of the present invention includes a sensing module for measuring voltage and current of an MOF terminal block under test; a 3-phase 4-wire power calculation unit for calculating a 3-phase 4-wire wattage value from the measured values of the voltage and current of the MOF terminal block; a three-phase, three-wire power calculation unit for calculating a three-phase, three-wire power consumption value from the measured values of the voltage and current of the MOF terminal block; and an MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire power calculator with the power value calculated by the three-phase, three-wire power calculator.

Here, the sensing module may include an R-phase voltage sensor sensing the R-phase PT end of the MOF terminal block; an R-phase current sensor for sensing the R-phase CT terminal of the MOF terminal block; an S-phase voltage sensor for sensing the S-phase PT end of the MOF terminal block; an S-phase current sensor for sensing the S-phase CT terminal of the MOF terminal block; a T-phase voltage sensor for sensing the T-phase PT end of the MOF terminal block; a T-phase current sensor for sensing the T-phase CT terminal of the MOF terminal block; and a video voltage sensor for sensing the video PT terminal of the MOF terminal block.

Here, the instrument interface for receiving information on power measurement from the instrument under test; and a meter inspection unit that determines whether the meter under test is normal by comparing the measured power value from the meter under test with the wattage value calculated by the 3-phase, 4-wire power calculation unit.

Here, the instrument interface may receive a metering pulse emitted as infrared light from the instrument under test.

Here, if the meter inspection unit determines whether the meter under test is normal, the three-phase, three-wire power calculation unit calculates a three-phase, three-wire power consumption value, and the MOF inspection unit determines whether the MOF under test is normal. .

Here, the MOF checking unit may determine that an abnormality exists in a phase in which an undermetering occurs in calculating an energy value in the three-phase, three-wire system when the MOF under test is determined to be abnormal.

An inspection device for a power metering device according to another aspect of the present invention includes a sensing module for measuring voltage and current of an MOF terminal block under test; a power calculation unit for calculating a 3-phase 4-wire power consumption value and a 3-phase 3-wire power consumption value from the measured values of the voltage and current of the MOF terminal block; a path switcher for converting the measured values of the voltage and current of the MOF terminal block outputted from the sensing module according to a power amount value calculation method and transferring the path to the power calculator; a device interface that receives information about power measurement from a device under test; a meter inspection unit comparing the measured power value from the meter under test with the wattage value calculated by the 3-phase, 4-wire system in the power calculation unit to determine whether the meter under test is normal; an MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire method in the power calculator with the power amount value calculated by the three-phase, three-wire method in the power calculator; and a test control unit controlling the path changer and the power calculator according to the calculation of the 3-phase 4-wire type power consumption value or the 3-phase 3-wire power amount value calculation.

Here, the path changer and the test control unit may form a separate add-on device independent of hardware.

Here, the test control unit may emit a trigger signal instructing MOF inspection when the instrument inspection unit determines whether the instrument under test is normal, or may emit the trigger signal when an inspector's operation is received.

An inspection method for a power metering device according to another aspect of the present invention includes measuring voltage and current of an MOF terminal block under test; Calculating a wattage value in a three-phase, four-wire system from the measured values of the voltage and current of the MOF terminal block; obtaining a power measurement value from a device under test; comparing the measured power value obtained from the device under test with the power value calculated by the three-phase, four-wire method to determine whether the device under test is normal; Calculating an electric power value in a three-phase, three-wire system from the measured values of the voltage and current of the MOF terminal block when it is determined that the instrument under test is normal; and determining whether the MOF under test is normal by comparing the power consumption value calculated for the three-phase, four-wire method with the power amount value calculated for the three-phase, three-wire method.

Here, in the step of obtaining the measured power value from the meter under test, a metering pulse may be received from the meter under test, which is a three-phase, four-wire watt-hour meter, and a metering value according to the number of metering pulses may be calculated and obtained.

Here, in the step of calculating the energy value for the 3-phase 4-wire system, the 3-wire 4-wire system energy value may be calculated based on the following equation.

Here, in the step of calculating the energy value by the three-phase, three-wire system, the three-wire system power value can be calculated based on the following equation.

Here, in the step of determining whether the instrument under test is normal, an error rate (%) can be obtained based on the following equation.

Here, in the step of determining whether the MOF to be tested is normal,

Power values of each phase may be compared according to the following equation.

Here, in the step of determining whether the MOF under test is normal, if the MOF under test is determined to be abnormal, it is determined that there is an abnormality in the phase in which undermetering occurred in calculating the energy value by the three-phase, three-wire method can do.

If the method and/or apparatus for checking the power metering device according to the spirit of the present invention having the above structure is implemented, there is an advantage in that the MOF of the power metering device can be inspected economically and efficiently.

The inspection method and/or apparatus for a power metering device of the present invention has advantages of reducing test costs such as labor costs and preventing potential losses due to MOF abnormality by not requiring additional personnel for MOF inspection.

The method and/or device for checking power metering devices of the present invention has advantages of creating a fair power trading environment and preventing civil complaints due to excessive errors.

1a and 1b are photographs showing defect types according to internal mixing of MOFs.
2a and 2b are photographs showing defect types according to internal mixing of MOFs.
3a and 3b are photographs showing defect types according to internal mixing of MOFs.
4 is a single line diagram of a domestic extra-high voltage power receiving facility.
5 is a flowchart illustrating an embodiment of a method for checking a power metering device according to the spirit of the present invention.
6 is a wiring schematic diagram showing the wiring relationship between the standard tester, the MOF terminal block, and the TTB during the watt-hour meter error test.
7 is a wiring schematic diagram showing a state in which an initial wiring structure is formed for an inspection method for a power metering device according to the spirit of the present invention;
8 is a wiring schematic diagram showing a wiring structure for calculating a value of an S-phase (P2) common in calculating a power value of a three-phase, three-wire type for MOF inspection.
9 is a wiring schematic diagram showing a wiring structure for calculating the value of the R phase (P1) common in calculating the power value of the three-phase, three-wire type for MOF inspection.
10 is a wiring diagram showing a wiring structure for calculating a value of a T phase (P3) common in calculating a three-phase, three-wire power consumption value for MOF inspection.
FIG. 11 is a flowchart illustrating a process of determining a defective image and calculating an error rate in detail in FIG. 5;
Fig. 12 is a block diagram showing a basic embodiment of a checking device for an electric power metering device;
FIG. 13 is a block diagram showing another embodiment of a form in which a checking device for a power metering device according to the spirit of the present invention can be constructed by minimally improving a conventional standard tester.
FIG. 14 shows another embodiment of a minimal form in which the inspection device for a power metering device according to the spirit of the present invention is used together with a conventional standard tester and performs only MOF inspection, which the conventional standard tester could not perform. block too.

In describing the present invention, terms such as first and second may be used to describe various components, but the components may not be limited by the terms. Terms are only for the purpose of distinguishing one element from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention.

When a component is referred to as being connected or connected to another component, it may be directly connected or connected to the other component, but it may be understood that another component may exist in the middle. .

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms include or include are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features or numbers, It can be understood that the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer description.

The present invention is a power metering device that simultaneously checks and determines whether non-technical power metering loss of power metering devices (wattmeters and accessories) has to be checked and determined with a dedicated tester for each wattmeter or accessory device as in the existing technology. As a technology for a comprehensive error tester, a method for measuring watt-hour meter errors (including instrument errors and wiring errors) and MOF errors with power metering information input through the voltage and current sensors of this comprehensive error tester and diagnosing normality is suggested. do.

In the description of the present invention, although the power value and the power value are not strictly distinguished for the convenience of convention and understanding, it is obvious that the accumulated value in unit time of the power value is the power value, and the power value is derived based on the power value. reveal

As shown in FIG. 4, a typical domestic extra-high voltage customer applies the same 3-phase 4-wire power metering method as the distribution system method. As a way to minimize the load imbalance of each phase of the distribution system, the neutral wire is not connected when connecting the extra-high voltage customer grid, and the transformer connection method is the △(1st: extra-high voltage)-Yg (2nd: low-voltage) method.

Therefore, since the power metering point is the primary side (Δ) of the transformer, the three-phase current maintains balance when normal. Equilibrium is maintained, according to Blondel's theorem, any metering method with at least 2 elements (3-phase 4-wire and 3-phase 3-wire) can be applied.

By utilizing these characteristics, not only the error of the watt-hour meter, which is an instrument, but also the error of the MOF can be simultaneously checked and any abnormalities can be diagnosed. For example, in the case of dividing into abc phases, a three-phase, three-wire power consumption value according to Equation 1 below and a three-phase four-wire power consumption value according to Equation 2 below may be simultaneously obtained and applied. By using this value and comparing it according to the review conditions to be followed, the difference in the value of the amount of power in phase A (considering the tolerance for measurement error) can be found, and this difference can eventually confirm whether there is an abnormality in the phase.

5 is a flowchart illustrating an embodiment of an inspection method for a power metering device that performs integrated error determination on a power metering device (electronic meter + MOF) according to the spirit of the present invention.

The inspection method for the illustrated power metering device includes measuring the voltage and current of the MOF terminal block under test (S110); Calculating a power value in a three-phase, four-wire system from the measured values of the voltage and current of the MOF terminal block (S120); Acquiring a measured power value from a device under test (S130); Comparing the measured power value obtained from the device under test with the power value calculated for the 3-phase, 4-wire method to determine whether the device under test is normal (S140); If it is determined that the meter under test is normal, calculating a power value in a three-phase, three-wire system from the measured values of the voltage and current of the MOF terminal block (S150); and determining whether the MOF under test is normal by comparing the power consumption value calculated according to the three-phase, four-wire method with the power amount value calculated according to the three-phase, three-wire method (S160).

In explaining the inspection method for the power metering device shown in FIG. 5, for convenience of understanding, the PSM 5003 standard tester for checking the error of a general watt-hour meter (meter) is changed to perform the inspection method for the power metering device shown. I will illustrate the process in detail.

6 is a wiring schematic diagram showing the wiring relationship between the standard tester, the MOF terminal block, and the TTB during the watt-hour meter error test.

TTB is an uninterruptible terminal block as a device that maintains an uninterrupted state on the load during inspection, and in reality, most error testers and inspection devices are equipped with sensors for testing (inspection) of the TTB.

The connection structure of the MOF terminal block (30), TTB (50), meter (40), and standard tester (10) shown in FIG. When the following method is applied to the standard tester 10 for measuring the error of the illustrated watt-hour meter 40, the MOF error as well as the incorrect wiring of the watt-hour meter 10 can be checked at the same time.

When calculating the power value with a 3-phase 3-wire method and when calculating the power value with a 3-phase 4-wire method, there are some differences in the wiring structures of the standard tester shown, and accordingly, a means for converting the wiring structure is required, but the present invention In explaining the principle of , each switched wiring structure will be shown as a changed wiring in FIG. 6 .

First, as the initial wiring structure, the MOF is the same as the standard tester for the error test of the watt-hour meter.

Error between the voltage (R, S, T, N)/current (R, S, T) sensor and instrument for each phase between the secondary side and TTB (Uninterruptible Terminal Block) Connect the metering pulse detection device for comparison.

3-phase 4-wire and 3-phase 3-wire metering values are calculated as follows from the voltage and current information measured for each phase in the illustrated comprehensive error tester, but when the R, S, and T phases are applied, for example, Equation 3 below Based on , a 3-wire 4-wire type power value (metered value) can be calculated, and a 3-wire 3-wire type power value (metered value) can be calculated based on Equation 4 below.

7 is a wiring schematic diagram showing a state in which the above-described initial wiring structure is formed for a method for checking a power metering device according to the spirit of the present invention. Processes (S110 to S140) for checking the meter (watt hour meter) according to the spirit of the present invention may be performed on the illustrated wiring structure.

In step S120 of FIG. 5, when the 3-wire 4-wire type power value is calculated according to Equation 3, in step S140, the total error tester calculates the power amount of the 3-phase 4-wire type based on Equation 5 below and The error rate (%) is obtained by comparing the measured value in the phase 4-wire watt-hour meter. To this end, a metering value according to the number of metering pulses may be calculated and obtained by receiving metering pulses from the three-phase, four-wire watt-hour meter.

(In Equation 5, P(3p4w) is a 3-phase 4-wire power consumption value calculated according to the spirit of the present invention even if it is not in the form of a comprehensive error tester)

At this time, if it is within the allowable error range set by the relevant law, it is determined to be normal, and if it is exceeded, it is determined to be abnormal (S149). If it is within the tolerance (normal), it goes to the MOF check step as shown in FIG. 5 .

을 구한다.

(계측오차감안)이면, 도 6에 도시한 10개의 전압·전류선이 착오 결선된 것으로 판단하고, 그렇지 않을 경우 다음 단계(MOF)를 점검한다.In the case of an abnormality exceeding the tolerance, the comprehensive tester measures or calculates through the current sensor

save

If it is (considering measurement error), it is determined that the 10 voltage/current lines shown in FIG. 6 are incorrectly wired, and if not, the next step (MOF) is checked.

이 유지되어야 한다. 그렇지 못한 경우는 계기내부의 CT(변류기)에 이상이 있거나, MOF의 CT(변류기)의 이상이 발생했을 때만 나타난다. PT는 점검에 대해서는 정해진 정격전압을 사용하므로 이상 여부를 쉽게 확인할 수 있어 추가 설명을 생략하겠다.Since the power metering point is the primary side (△) of the transformer, unless there is a problem with the device and connection, etc.

this should be maintained If not, it appears only when there is an error in the CT (current transformer) inside the instrument or when an error occurs in the CT (current transformer) of the MOF. Since the PT uses a fixed rated voltage for inspection, it is easy to check whether there is an abnormality, so additional explanation will be omitted.

8 is a wiring diagram showing a wiring structure for calculating the value of the S-phase (P2) common in calculating the value of the three-phase, three-wire power consumption for checking the MOF among the inspection methods for the power metering device according to the spirit of the present invention. It is an overview.

9 is a wiring diagram showing a wiring structure for calculating the value of the R phase (P1) common in calculating the value of the three-phase, three-wire type power consumption for checking the MOF among the inspection methods for the power metering device according to the spirit of the present invention. It is an overview.

10 is a wiring diagram showing a wiring structure for calculating the value of the T phase (P3) common in calculating the value of the three-phase, three-wire type power consumption for checking the MOF among the inspection methods for the power metering device according to the spirit of the present invention. It is an overview.

When performing the MOF check, the power value or energy value of the 3-phase 4-wire type based on the power in Equation 3 and the power value or power value of the 3-phase 3-wire type based on the power in Equation 4 above calculated by the comprehensive error tester It can be compared as shown in Equation 6 below.

If all the values of Equation 6 are within the allowable error range set by the relevant laws, it is determined to be normal, and if any one is exceeded, it is determined to be abnormal.

11 illustrates a process of determining a defective image and calculation of an error rate while performing the inspection method for the power metering device according to the flowchart of FIG. 5 by reflecting the above-described equations.

Next, an actual case in which the MOF is determined to be defective through the above-described process will be described.

This case is about an MOF that was found to be abnormal as a result of inspection with an actual MOF tester, and is a case where a failure occurred due to secular change or external surge.

The faulty MOF specifications are current transformer ratio: 10/5A, voltage ratio: 13,200/110V, rated load: PT (3*25VA), CT (3*25VA), precision grade: 05W, and during load operation, MOF secondary side limit An abnormality occurred in which the current was measured 600% less than the other phases.

1a and 1b show a disassembled state of a failed MOF, in which the MOF secondary current transformer coil is distorted due to manufacturing defects or accumulated external disturbances. Also, the twisted coil is connected to the enclosure.

A converter is formed, and the current flowing in the coil is distributed to other converters, so that the watt-hour meter measures a smaller amount of current than the actual current flowing in the primary side. In the end, the electricity price was reflected as a value measured less than the actual usage. The abnormal MOF in which the transformer ratio has been abnormal through inspection so far is of this type, and the case of over-metering does not occur, but due to leakage, it is under-metering than the actual usage.

Next, a method for determining a phase exceeding the tolerance is described. In the resultant values of R, S, and T in Equation 6, the phase underestimated (-%XX) can be determined as an abnormal phase. For example, when the current of one phase is undermeasured by 10%, it can be finally determined that the corresponding phase has an abnormality.

Next, detailed configurations of various embodiments of an inspection apparatus for a power metering device that performs the above-described inspection method according to the spirit of the present invention will be described.

12 is a block diagram showing a basic embodiment of a checking device for an electric power metering device. The illustrated inspection device is a single inspection device, and is configured to determine the integrated error of both the electronic meter of the power metering device and the MOF according to the spirit of the present invention. Accordingly, it can be used instead of the standard tester as shown in FIG. 5.

The inspection device for the illustrated power metering device includes a sensing module 110 for measuring voltage and current of the MOF terminal block under test; a 3-phase 4-wire power calculation unit 120 for calculating a 3-phase 4-wire wattage value (or power value) from the measured values of the voltage and current of the MOF terminal block; a three-phase, three-wire power calculation unit 150 that calculates a three-phase, three-wire power amount value (or power value) from the measured values of the voltage and current of the MOF terminal block; a meter interface 190 that receives information about power measurement from a device under test; a meter inspection unit 140 that determines whether the meter under test is normal by comparing the measured power value from the meter under test with the wattage value calculated by the three-phase, four-wire power calculation unit 120; and an MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire power calculator 120 with the power value calculated by the three-phase, three-wire power calculator 150 ( 160) may be included.

The sensing module 110, similar to the case of the general standard tester shown in FIG. 6, includes an R-phase voltage sensor for sensing the R-phase PT terminal of the MOF terminal block; an R-phase current sensor for sensing the R-phase CT terminal of the MOF terminal block; an S-phase voltage sensor for sensing the S-phase PT end of the MOF terminal block; an S-phase current sensor for sensing the S-phase CT terminal of the MOF terminal block; a T-phase voltage sensor for sensing the T-phase PT end of the MOF terminal block; a T-phase current sensor for sensing the T-phase CT terminal of the MOF terminal block; and a video voltage sensor for sensing the video PT terminal of the MOF terminal block.

The 3-phase 4-wire power calculation unit 120 may calculate a power value (or power value) in a 3-phase 4-wire type based on Equation 3 described above.

The 3-phase 3-wire power calculation unit 150 may calculate a power value (or power value) based on Equation 4 above using a 3-phase, 3-wire method.

In the case of a currently widely used electronic instrument, the instrument interface 190 may be implemented as an infrared light receiving device that receives a metering pulse emitted by the electronic instrument as an infrared ray. In this case, the meter check unit 140 may count the metering pulses and obtain a metering value by the meter under test based on the counting of the metering pulses.

In addition, the instrument inspection unit 140 may determine whether the time under test is normal/abnormal according to the conditions shown in Equation 5 above.

The MOF checking unit 160 may determine whether the MOF to be tested is normal/abnormal according to the conditions shown in Equation 6 above.

Looking at the temporal successive relationship of the operation of each component, first, the 3-phase 4-wire power calculation unit 120 calculates the 3-phase 4-wire power consumption value, and the instrument inspection unit 140 determines whether the instrument under test is normal. When is determined, the three-phase, three-wire power calculator 150 calculates a three-phase, three-wire power amount value, and the MOF checker 160 determines whether the MOF under test is normal.

In addition, when the MOF under test is determined to be abnormal, the MOF checking unit 140 may determine that there is an abnormality in a phase in which an undermetering occurs in calculating an energy value in the three-phase, three-wire system.

FIG. 13 is a block diagram showing another embodiment of a form in which a checking device for a power metering device according to the spirit of the present invention can be constructed by minimally improving a conventional standard tester.

The inspection device for the power metering device of the illustrated embodiment includes a sensing module 111 for measuring voltage and current of the MOF terminal block under test; a power calculator 121 for calculating a 3-phase 4-wire power consumption value and a 3-phase 3-wire power consumption value from the measured values of the voltage and current of the MOF terminal block; a path switcher 131 that converts paths of the measured values of the voltage and current of the MOF terminal block output from the sensing module 111 according to a power amount value calculation method and transfers them to the power calculator; a meter interface 190 that receives information about power measurement from a device under test; a meter inspection unit 141 for determining whether the meter under test is normal by comparing the measured power value from the meter under test with the power value calculated by the power calculation unit 121 for a 3-phase, 4-wire system; MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the power calculator 121 for the three-phase, four-wire method with the power value calculated for the three-phase, three-wire method in the power calculator 121 (161); and a test controller 180 that controls the path changer and the power calculation unit according to the calculation of the 3-phase 4-wire power consumption value or the 3-phase 3-wire power consumption value calculation.

If the inspection device for the power metering device of this embodiment is divided from the hardware point of view, a set of sensors mounted on the PT and CT terminals of the R, S, and T phases of the MOF terminal block, which is almost the same as the case shown in FIG. It can be seen as an improved standard tester for the general standard tester shown and an add-on device for function expansion indicated by A in the drawing.

A set of the sensors is implemented as the sensing module 111 . The improved standard tester includes the power calculator 121, the instrument interface 190, the instrument checker 141, and the MOF checker 161.

The add-on device may include the route changer 131 and the test control unit 180 indicated by A in the drawing.

In order to improve the conventional standard tester to the improved standard tester, a three-phase, three-wire power (quantity) value calculation function is added to the program module corresponding to the power calculation unit 121 in terms of software, and the MOF Add a program module that performs the function of the inspection unit 161, and in terms of hardware, add a terminal that can receive a trigger signal from the test control unit 180 or identify the trigger signal to an existing terminal You just need to add a function. Here, the trigger signal instructs MOF inspection, instructs the power calculation unit 121 to calculate a three-phase, three-wire power (amount) value, and activates the MOF inspection unit 161 .

Depending on the implementation, the test control unit 180 may emit the trigger signal when the instrument inspection unit 140 determines whether the instrument under test is normal, or emit the trigger signal when an inspector's manipulation is input. In the former case, the integrated inspection is automated, but the improvement request for the general standard testing machine is high, and in the latter case, the improvement request for the general standard testing machine is low, and the inspector determines whether the instrument under test is normal.

The path converter 131 is installed between the improved standard tester and the sensing module 110 to sequentially form the wiring structure shown in FIGS. 6 to 9, Paths between the power calculators 121 may be switched.

FIG. 14 shows another embodiment of a minimal form in which the inspection device for a power metering device according to the spirit of the present invention is used together with a conventional standard tester and performs only MOF inspection, which the conventional standard tester could not perform. It is a block diagram.

The inspection device for the power metering device of the illustrated embodiment includes a sensing module 110 for measuring voltage and current of the MOF terminal block under test; a 3-phase 4-wire power calculation unit 122 for calculating a 3-phase 4-wire wattage value from the measured values of the voltage and current of the MOF terminal block; a three-phase, three-wire power calculation unit 152 for calculating a three-phase, three-wire power consumption value from the measured values of the voltage and current of the MOF terminal block; and an MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire power calculator 122 with the power value calculated by the three-phase, three-wire power calculator 152 ( 162) may be included.

In actual use, the inspector carries the general standard tester shown in FIG. 6 and the inspection device of this embodiment together, and first checks the electronic meter of the power meter for abnormalities (errors) using the standard tester, and then checks the electronic meter. If there is no abnormality, the MOF inspection according to the spirit of the present invention can be performed by removing the standard tester and connecting the inspection device of the present embodiment.

Compared to the case of FIG. 12, the inspection apparatus for the power metering device of the illustrated embodiment has some components omitted, and since each remaining component is almost the same as that of FIG. 12, duplicate descriptions will be omitted.

Those skilled in the art to which the present invention pertains should understand that the embodiments described above are illustrative in all respects and not limiting, since the present invention can be embodied in other specific forms without changing the technical spirit or essential characteristics thereof. only do The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

110: sensing module 120: 3-phase 4-wire power calculation unit
121: power calculation unit 131: path switcher
150: 3-phase 3-wire power calculation unit 140: instrument inspection unit
160: MOF inspection unit 180: test control unit
190: instrument interface

Claims (16)

A sensing module that measures the voltage and current of the MOF terminal block under test;
a 3-phase 4-wire power calculation unit for calculating a 3-phase 4-wire wattage value from the measured values of the voltage and current of the MOF terminal block;
a three-phase, three-wire power calculation unit for calculating a three-phase, three-wire power consumption value from the measured values of the voltage and current of the MOF terminal block; and
MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire power calculator with the power value calculated by the three-phase, three-wire power calculator
Inspection device for a power metering device comprising a.
According to claim 1,
The sensing module,
an R-phase voltage sensor for sensing the R-phase PT end of the MOF terminal block;
an R-phase current sensor for sensing the R-phase CT terminal of the MOF terminal block;
an S-phase voltage sensor for sensing the S-phase PT end of the MOF terminal block;
an S-phase current sensor for sensing the S-phase CT terminal of the MOF terminal block;
a T-phase voltage sensor for sensing the T-phase PT end of the MOF terminal block;
a T-phase current sensor for sensing the T-phase CT terminal of the MOF terminal block; and
Zero phase voltage sensor for sensing the phase PT terminal of the MOF terminal block
Inspection device for a power metering device comprising a.
According to claim 1,
a device interface that receives information about power measurement from a device under test; and
A meter check unit for determining whether the meter under test is normal by comparing the measured power value from the meter under test with the power value calculated by the 3-phase, 4-wire power calculator
A check device for a power metering device further comprising a.
According to claim 3,
The instrument interface is
An inspection device for a power metering device that is an infrared light receiving device that receives metering pulses emitted by infrared rays from the instrument under test.
According to claim 3,
When the instrument inspection unit determines that the instrument under test is normal,
The inspection device for a power metering device in which the three-phase, three-wire power calculation unit calculates a three-phase, three-wire power consumption value, and the MOF inspection unit determines whether the MOF under test is normal.
According to claim 1,
The MOF inspection unit,
When the MOF under test is determined to be abnormal, it is determined that there is an abnormality in the phase in which undermetering has occurred in calculating the value of the electric energy in the three-phase, three-wire system.
A sensing module that measures the voltage and current of the MOF terminal block under test;
a power calculation unit for calculating a 3-phase 4-wire power consumption value and a 3-phase 3-wire power consumption value from the measured values of the voltage and current of the MOF terminal block;
a path switcher for converting the measured values of the voltage and current of the MOF terminal block outputted from the sensing module according to a power amount value calculation method and transferring the path to the power calculator;
a device interface that receives information about power measurement from a device under test;
a meter inspection unit comparing the measured power value from the meter under test with the wattage value calculated by the 3-phase, 4-wire system in the power calculation unit to determine whether the meter under test is normal;
an MOF checking unit that determines whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire method in the power calculator with the power amount value calculated by the three-phase, three-wire method in the power calculator; and
A test control unit for controlling the path switcher and the power calculation unit according to the three-phase, four-wire type power value calculation or the three-phase, three-wire type power amount value calculation
Inspection device for a power metering device comprising a.
According to claim 7,
The inspection device for a power metering device in which the path changer and the test control unit form a separate add-on device independent in terms of hardware.
According to claim 7,
The test control unit,
An inspection device for a power metering device that emits a trigger signal instructing MOF inspection when the meter inspection unit determines whether the meter under test is normal or emits the trigger signal when an inspector's operation is input.
Measuring voltage and current of the MOF terminal block under test;
Calculating a wattage value in a three-phase, four-wire system from the measured values of the voltage and current of the MOF terminal block;
obtaining a power measurement value from a device under test;
comparing the measured power value obtained from the device under test with the power value calculated by the three-phase, four-wire method to determine whether the device under test is normal;
Calculating an electric power value in a three-phase, three-wire system from the measured values of the voltage and current of the MOF terminal block when it is determined that the instrument under test is normal; and
Determining whether the MOF under test is normal by comparing the power value calculated by the three-phase, four-wire method with the power value calculated by the three-phase, three-wire method.
Inspection method for a power metering device comprising a.
According to claim 10,
In the step of obtaining the measured power value from the device under test,
An inspection method for a power metering device that receives metering pulses from the meter under test, which is a three-phase, four-wire watt-hour meter, and calculates and obtains a metering value according to the number of metering pulses.
According to claim 10,
In the step of calculating the energy value in the 3-phase 4-wire system, the 3-wire 4-wire system energy value is calculated based on the following equation.

According to claim 12,
In the step of calculating the energy value in the three-phase, three-wire system, the three-wire three-wire system energy value is calculated based on the following equation.

According to claim 13,
In the step of determining whether the instrument under test is normal, an error rate (%) is obtained based on the following equation.

According to claim 13,
In the step of determining whether the MOF to be tested is normal,
An inspection method for a power metering device that compares power values of each phase according to the following equation.

According to claim 15,
In the step of determining whether the MOF to be tested is normal,
When the MOF under test is determined to be abnormal, it is determined that there is an abnormality in the phase in which under-metering occurs in calculating the value of energy in the three-phase, three-wire system.

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