KR-102964007-B1 - 3-Phase Watt Hour Meter Insulation Resistance Measurement Device

Abstract

The insulation resistance measuring device for a three-phase power meter according to the present invention may include: a measuring terminal block having terminal pins arranged to conform to the specifications of the power meter; a line resistance measuring unit that measures the line resistance between two terminal pins among the terminal pins; a multi-relay unit that connects only two selected terminal pins among the terminal pins of the measuring terminal block to the line resistance measuring unit; a measuring control unit that instructs line resistance measurement while sequentially changing the two terminal pins connected to the line resistance measuring unit for a predetermined pair of terminal pins to be inspected consisting of two terminal pins among the terminal pins; and a result output unit that outputs a result for an abnormal value occurring among the line resistance values measured for the pair of terminal pins to be inspected.

Inventors

• 김시우
• 문정기
• 주영훈

Assignees

• 한국전력공사

Dates

Publication Date

20260512

Application Date

20240722

Claims (7)

1. A measuring terminal block with terminal pins arranged to meet the specifications of a power meter; A line resistance measuring unit for measuring the line resistance between two terminal pins among the above terminal pins; A multi-relay unit that connects only two selected terminal pins among the terminal pins of the above-mentioned measuring terminal block to the above-mentioned inter-line resistance measuring unit; A measurement control unit that instructs inter-line resistance measurement while sequentially changing two terminal pins connected to the inter-line resistance measuring unit for a predetermined pair of terminal pins to be inspected, consisting of two of the above terminal pins; and A result output unit that outputs results regarding abnormal values occurring among the inter-line resistance values measured for the above-mentioned terminal pin pairs subject to inspection. Includes, The above measurement control unit is, A three-phase power meter insulation resistance measuring device that performs line-to-line resistance measurements in the order according to the table below for a number of terminal pins as the predetermined pairs of terminal pins to be inspected according to the specifications of the power meter.
2. In paragraph 1, The above measurement control unit is, A three-phase power meter insulation resistance measuring device that receives specification information of a three-phase power meter to be inspected and determines predetermined pairs of terminal pins to be inspected according to the received specification information.
3. In paragraph 2, The above result output unit is, A three-phase power meter insulation resistance measuring device that determines a resistance threshold value judged as an abnormal value according to the above specification information.
4. In paragraph 1, A terminal spacing adjustment unit capable of adjusting the spacing of the terminal pins of the measuring terminal block to conform to the specifications of the power meter. A three-phase power meter insulation resistance measuring device further comprising
5. In paragraph 4, The above terminal spacing adjustment unit is, A three-phase power meter insulation resistance measuring device that guides manual movement at predetermined intervals using a tooth structure and an elastic material in the direction of pressure applied to each tooth, and provides a predetermined fixing force for the moved interval.
6. In paragraph 4, The above terminal spacing adjustment unit is, A three-phase power meter insulation resistance measuring device including a motor that automatically adjusts to an interval suitable for the specifications according to power meter specification information.
7. delete

Description

3-Phase Watt Hour Meter Insulation Resistance Measurement Device The present invention relates to equipment that prevents safety accidents caused by insulation failure by rapidly performing a one-stop resistance measurement of a power meter to pre-check for abnormalities before installation. More specifically, when measuring resistance between terminals using a conventional general tester for electricity meters, resistance must be measured at least 18 times and up to 30 times depending on the type of electricity meter. However, by using the One Stop 3-phase electricity meter terminal resistance measuring device, it is possible to measure resistance between all terminals in a single measurement, thereby allowing for the rapid identification of equipment abnormalities in advance and preventing safety accidents caused by internal insulation failures in the electricity meter. Table 1 below shows the current status of low-voltage electronic power meters. Table 2 below shows the current status of high-voltage standard electronic power meters. Electricity meters, which measure power consumption to collect usage fees, require fair measurement and reliability; therefore, they undergo regular inspections and have replacement periods stipulated by law for each meter. Additionally, situations arise where electricity meters are replaced or removed due to various reasons after installation. Table 3 below shows the validity period for electricity meter calibration. The implementation standards for pre-installation inspections of electricity meters, introduced in 2023 to strengthen safety management at internal wiring work sites, prevent safety accidents caused by the burning of electricity meters during work by conducting pre-installation inspections regardless of whether the meter is new or reused. According to the regulations, the resistance of the electricity meter to be newly attached must be measured before work begins, and installation is permitted only if it is normal. Additionally, if the resistance of the electricity meter is measured using a standard tester and the terminal resistance is less than 30 kΩ or the insulation resistance is less than 5 MΩ, it is deemed abnormal, and installation work must be stopped immediately. Table 4 below shows examples of internal circuit and resistance measurement standards for a high-voltage 3-phase 4-wire standalone electronic power meter (G type). As shown in Table 4 above, in the case of the G-type 3-phase 4-wire standalone electronic power meter, starting with the resistance measurement between the 1S-2S terminals, the resistance between the 1S-3S, 1S-0S, 1S-0L, 1S-3L, and 1S-2L terminals must be measured. At the 2S terminal, the resistance between the 2S-3S, 2S-0S, 2S-0L, 2S-3L, and 2S-1L terminals must be measured; at the 3S terminal, the resistance between the 3S-0S, 3S-0L, 3S-2L, and 3S-1L terminals must be measured; and at the 0S terminal, the resistance between the 0S-3L, 0S-2L, and 0S-1L terminals must be measured. Therefore, a total of 18 resistance measurements between terminals must be taken. Table 5 below shows examples of internal circuit and resistance measurement standards for a 3-phase 4-wire transformer-equipped electronic power meter (G-type, high voltage). As shown in Table 5 above, the process becomes more complex in the case of the G-type and high-voltage electronic power meter with a 3-phase 4-wire transformer. Starting with resistance measurements between P1-P2, P1-P3, and P1-P0, resistance measurements must be taken between P2-P3 and P2-P0, and between P3-P0. Additionally, resistance measurements must be taken between the 1S-P1, 1S-P2, 1S-P3, 1S-P0, 1L-P1, 1L-P2, 1L-P3, 1L-P0, and between the 2S terminals, between 2S-P1, 2S-P2, 2S-P3, 2S-P0, 2L-P1, 2L-P2, 3S-P0, 3L-P1, 3L-P2, 3L-P3, and 3L-P0. If all of these steps are performed, a total of 30 resistance measurements between terminals must be conducted. Although this is a pre-installation inspection intended to prevent safety accidents, performing 18 to 30 inter-terminal resistance measurements is time-consuming, and since omissions or omissions are common, it is a procedure that requires significant attention and effort from the worker. If even a single inter-terminal resistance measurement is missed out of a total of 30, it becomes impossible to verify any internal abnormalities in the power meter, which can lead to safety accidents. Figures 1a to 1d are photographs showing examples of safety accidents in the field of internal wiring instruments. Specifically, Figure 1a shows an example of instrument burnout due to insulation failure, Figure 1b shows an example of a short circuit accident between lines on the power side, Figure 1c shows an example of instrument burnout due to insulation failure, and Figure 1d shows an example of an arc occurring during instrument replacement. Table 6 below illustrates the status of safety accidents in the field of internal wiring instruments (2015–2022). Arc burn an