Watt hour meter and anomaly detection method of watt hour meter

Abstract

The electricity metering unit (12) calculates the consumer's electricity consumption based on the current and voltage values ​​of the terminal fittings (14) of the electricity meter (11) and outputs electricity consumption data. The temperature detection unit (31) outputs temperature data indicating the internal temperature of the electricity meter (11). When the temperature data exceeds a predetermined temperature threshold and the electricity consumption data is equal to or less than a predetermined electricity consumption threshold, the determination processing unit (32) determines that the terminal fittings (14) are abnormal.

Description

[Technical Field]

[0001] This disclosure relates to electricity meters, and in particular to techniques for detecting overheating caused by malfunctions in electricity meters. [Previous Technology]

[0002] Electricity meters used to accumulate and measure consumer electricity consumption need to be protected against damage to the meters and the resulting damage to the consumer's electrical equipment.

[0003] For example, Patent Document 1 discloses an electricity meter that outputs an alarm when the temperature of the meter's conductive parts and terminals is equal to or higher than a certain value. Furthermore, Patent Document 2 discloses an electricity meter that, by measuring the temperature inside the meter and the temperature at a location closer to the outside of the meter, determines whether the fire originated from the inside or outside when the meter burns out, and records the determination result. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2010-19680 [Patent Document 2] Japanese Patent Application Publication No. 2018-72248 [Summary of the Invention]

[0005] [Problem to be Solved by the Invention] The main reason for the overheating and burning of electricity meters is that the screws at the terminals of the electricity meter are not secure enough or are loose, resulting in poor contact. Therefore, when detecting the temperature rise inside the electricity meter, a temperature sensor is usually installed near the terminals. However, when the consumer consumes a large amount of electricity, the terminals will also generate heat. Therefore, the temperature sensor installed near the terminals cannot distinguish whether the temperature rise of the electricity meter is due to poor contact at the terminals or whether the consumer is consuming too much electricity. Therefore, it is difficult to accurately detect the heat caused by poor contact at the terminals of the electricity meter.

[0006] This disclosure is made to solve the above-mentioned problems and aims to provide a detection technology to distinguish between the heat caused by poor contact at the terminals of an electricity meter and the heat caused by the electricity consumption of consumers.

[0007] [Means for solving the problem] The electricity meter disclosed herein includes: terminal fittings for connecting a power cord; an electricity metering unit for calculating the consumer's electricity consumption based on the current and voltage values ​​of the terminal fittings and outputting electricity consumption data representing the aforementioned electricity consumption; a temperature detection unit for outputting temperature data representing the internal temperature of the aforementioned electricity meter; and a determination processing unit for determining that the aforementioned terminal fittings are malfunctioning when the aforementioned temperature data exceeds a predetermined temperature threshold and the electricity consumption data is equal to or less than a predetermined electricity consumption threshold.

[0008] [Effect of the Invention] According to the method for detecting the temperature rise of an electricity meter disclosed herein, it is possible to distinguish between the heat caused by poor contact at the terminals of the electricity meter and the heat caused by the electricity consumption of the consumer.

[0009] The purpose, features, appearance and advantages of this disclosure will become more apparent from the following detailed description and accompanying drawings.

Implementation Method

[0011] [Forms for Implementing the Invention] [Example 1] Figure 1 is a configuration diagram of the electricity meter 11 in Example 1. The electricity meter 11 is a so-called smart meter, including an electricity metering unit 12 for measuring the electricity consumption of consumers, a communication terminal unit 13 for periodically transmitting the measured electricity consumption to an upper-level server, and terminal fittings (i.e., terminal metal fittings) 14 for connecting the power line supplying power to consumers. The electricity consumption measured by the electricity meter 11 is transmitted to the upper-level server, allowing managers to remotely understand the electricity consumption.

[0012] The meter 11 includes, for example, a housing 15 molded from resin. Furthermore, the meter 11 has terminal fittings 14, which include: a lead-line side terminal fitting 14a for connecting a lead-line from a distribution line, and a residential side terminal fitting 14b for connecting a lead-line from a residential distribution panel. In this embodiment, the meter 11 is a single-phase three-wire meter. The lead-line side terminal fitting 14a consists of three terminal fittings 1S, 2S, and 3S connecting to the power supply line; the residential side terminal fitting 14b consists of three terminal fittings 1L, 2L, and 3L connecting to the lead-line from the distribution panel.

[0013] Figure 2 is a functional block diagram of the electricity meter 11 of Embodiment 1. As shown in Figure 2, the power metering unit 12 of the electricity meter 11 includes a voltage detection unit 21, a first current detection unit 22, a second current detection unit 23, a clock 24, a power calculation unit 25, a device control unit 26, a memory unit 27, and an external communication unit 28.

[0014] The voltage detection unit 21 detects the voltage value between terminal fitting 1S and terminal fitting 1L, and the voltage value between terminal fitting 3S and terminal fitting 3L. The voltage values ​​detected by the voltage detection unit 21 are used as voltage value data and transmitted to the power calculation unit 25.

[0015] The first current detection unit 22 detects the current value between terminal fitting 1S and terminal fitting 1L, and the second current detection unit 23 detects the current value between terminal fitting 3S and terminal fitting 3L. The current values ​​detected by the first current detection unit 22 and the second current detection unit 23 are used as current value data and transmitted to the power calculation unit 25.

[0016] Clock 24 outputs the current year, month, day, hour, minute, and second time data to device control unit 26.

[0017] The power calculation unit 25 calculates the amount of electricity per unit time using voltage data obtained from the voltage detection unit 21 and current data obtained from the first current detection unit 22 and the second current detection unit 23. The amount of electricity calculated by the power calculation unit 25 is transmitted to the device control unit 26 as electricity data.

[0018] The device control unit 26 transmits the power data obtained from the power calculation unit 25 and the time data obtained from the clock 24 to the memory unit 27. The memory unit 27 stores the power data and time data received from the device control unit 26 in association.

[0019] The device control unit 26 may request the memory unit 27 to transmit stored power data and time data to the device control unit 26. The memory unit 27, which is requested to transmit power data and time data, transmits the stored power data and time data to the device control unit 26. The device control unit 26 inputs the power data and time data received from the memory unit 27 to the external communication unit 28.

[0020] The external communication unit 28 transmits the power data and time data input from the device control unit 26 to the communication terminal unit 13.

[0021] The communication terminal unit 13 includes a temperature detection unit 31, a device control unit 32, a memory unit 33, a wireless communication unit 34, and an external communication unit 35. In addition, the communication terminal unit 13 is connected to the upper-level server 41 of the communication terminal unit 13 via wireless communication.

[0022] The temperature detection unit 31 is a temperature sensor that periodically measures the internal temperature of the meter 11, specifically, it is a temperature sensor that periodically measures the temperature around the communication terminal 13. The temperature detection unit 31 transmits the measured temperature value as temperature data to the device control unit 32.

[0023] The device control unit 32 transmits the temperature data received from the temperature detection unit 31 to the memory unit 33. In addition, the device control unit 32 transmits the power data and time data received by the external communication unit 35 from the power metering unit 12 to the memory unit 33.

[0024] Furthermore, the device control unit 32 operates as a determination processing unit, which determines whether the overheating of the terminal fitting 14 is due to an abnormality in the terminal fitting 14 (e.g., poor contact) or excessive power consumption by the consumer. When the device control unit 32 determines that the overheating of the terminal fitting 14 is caused by an abnormality in the terminal fitting 14, it outputs a terminal fitting abnormality notification indicating this fact. This determination processing procedure will be described in detail later.

[0025] The memory unit 33 stores temperature data, power data, and time data received from the device control unit 32. The device control unit 32 may request the memory unit 33 to transmit the stored power data, time data, and temperature data to itself. The memory unit 33, which is requested to transmit time data and temperature data to the device control unit 32, transmits the stored power data, time data, and temperature data to the device control unit 32. The device control unit 32 inputs the power data, time data, and temperature data received from the memory unit 33, as well as the aforementioned terminal hardware abnormality notification, to the wireless communication unit 34.

[0026] The wireless communication unit 34 transmits the power data, time data, temperature data, and terminal hardware abnormality notifications input from the device control unit 32 to the communication unit of the upper server 41 via wireless communication.

[0027] The external communication unit 35 communicates with the external communication unit 28 of the power metering unit 12, receives power data and time data sent from the external communication unit 28, and sends them to the device control unit 32.

[0028] The upper-level server 41 receives power data, time data, temperature data, and terminal hardware abnormality notifications sent from the wireless communication unit 34 of the communication terminal unit 13. The received data will be sent to the administrator. In this way, the administrator can know in advance which meter 11 may burn out.

[0029] In addition to the general electricity meter function of measuring the electricity consumption of consumers, the electricity meter 11 also has the function of sending a terminal hardware abnormality notification to the upper server 41 when the terminal hardware 14 is overheated due to abnormality.

[0030] Hereinafter, referring to the flowchart in FIG3, the process by which the meter 11 determines whether the heating of the terminal fitting 14 is caused by an abnormality of the terminal fitting 14 will be explained. This process is mainly performed by the device control unit 32 of the communication terminal unit 13.

[0031] The device control unit 32 periodically (e.g., every 5 minutes) acquires the temperature data inside the meter 11 measured by the temperature detection unit 31 (step S101). The device control unit 32 determines whether the temperature data exceeds a predetermined temperature threshold (e.g., 60°C) (step S102). If the temperature data does not exceed the temperature threshold (step S102: No), the device control unit 32 determines that the temperature is not abnormal and returns to step S101 to continue monitoring the temperature data.

[0032] If the temperature data exceeds the temperature threshold (step S102: Yes), the device control unit 32 determines that the temperature is abnormal and obtains the power consumption data for the same period as the temperature data from the power metering unit 12, that is, the power consumption data associated with the time data for the same period as the temperature data (step S103). Then, the device control unit 32 determines whether the obtained power consumption data exceeds a predetermined power consumption threshold, for example, 500Wh (step S104). If the power consumption data exceeds the power consumption threshold (step S104: Yes), the device control unit 32 determines that the heating of the terminal hardware 14 is caused by excessive power consumption by the consumer (the terminal hardware 14 is not abnormal) and returns to step S101 to continue monitoring the temperature data.

[0033] If the power data does not exceed the power threshold (step S104: No), the device control unit 32 determines that the overheating of the terminal hardware 14 is caused by an abnormality in the terminal hardware 14 (step S105), and sends a terminal hardware abnormality notification to the upper-level server 41 through the wireless communication unit 34 to inform the terminal hardware 14 of the abnormality (step S106). At this time, the device control unit 32 can transmit the power data, time data, and temperature data to the upper-level server 41 to notify the administrator.

[0034] According to this embodiment, the electricity meter 11 can distinguish between heat generation caused by poor contact of the terminal fitting 14 and heat generation caused by the consumer's electricity consumption. Furthermore, when the electricity meter 11 determines that the temperature rise inside the meter 11 detected by the temperature detection unit 31 is caused by an abnormality in the terminal fitting 14, the meter 11 sends a terminal fitting abnormality notification to the upper server 41, allowing the administrator to quickly grasp the abnormality of the terminal fitting 14. This prevents damage to the electricity meter 11 and the consumer's electrical equipment caused by the heat generation due to the abnormality of the terminal fitting 14.

[0035] In the meter 11 according to this embodiment, the temperature is measured by a temperature detection unit 31 provided in the communication terminal 13. The temperature detection unit 31 detects the ambient temperature of the communication terminal 13, which rises due to convection within the casing 15 of the meter 11 caused by heat generated by the terminal fittings 14. Since the communication terminal 13 is far from the terminal fittings 14, which is a heat source, the communication terminal 13 is easily affected by the ambient temperature, and it may be difficult to accurately measure the internal temperature of the meter 11 that rises due to heat generated by the terminal fittings 14.

[0036] Therefore, the meter 11 has the function of acquiring ambient temperature data representing the ambient temperature of the area where the meter 11 is installed. The device control unit 32 can detect only the temperature rise inside the meter 11 and determine whether the temperature rise is caused by an abnormality in the terminal fitting 14 by calculating the difference between the temperature data measured by the temperature detection unit 31 and the ambient temperature. Specifically, the device control unit 32 can subtract the ambient temperature data from the temperature data measured by the temperature detection unit 31 and use the result as the temperature data to be compared with a predetermined temperature threshold. In addition, the ambient temperature data of the area where the meter 11 is installed can be, for example, data that can be obtained by the Japan Meteorological Agency through the network, and is periodically transmitted from the upper server 41 to the device control unit 32 via the wireless communication unit 34.

[0037] There are advantages to placing the temperature detection unit 31 in the communication terminal unit 13. As with a typical smart meter, if the power metering unit 12 and the communication terminal unit 13 in the meter 11 are independent structures, only the communication terminal unit 13 can be replaced. Furthermore, by replacing the communication terminal unit of an existing smart meter that does not have a temperature detection function with the communication terminal unit 13 of this embodiment, the effects of this embodiment can be obtained.

[0038] [Example 2] Since a consumer's electricity consumption varies over time, the heat generated by excessive electricity consumption is usually temporary. On the other hand, heat generated due to an abnormality in the terminal fitting 14 is expected to last for a longer period of time. Therefore, in Example 2, the condition for determining that the temperature rise inside the meter 11 is caused by an abnormality in the terminal fitting 14 is expanded to include: the temperature rise is continuous. Furthermore, the configuration of the meter 11 in Example 2 is similar to that in Example 1 (Figures 1 and 2).

[0039] Figure 4 is a flowchart showing the process by which the meter 11 in Embodiment 2 determines whether the overheating of the terminal fitting 14 is caused by an abnormality in the terminal fitting 14.

[0040] The flowchart in Figure 4 is obtained by adding step S110 to the flowchart in Figure 3. Since the other steps are the same as in Figure 3, only step S110 will be described here.

[0041] When the determination in step S102 is "yes" and the determination in step S104 is "no", that is, when the temperature data measured by the temperature detection unit 31 exceeds the temperature threshold and the consumer's power data is equal to or less than the power threshold, then step S110 is executed. In step S110, the device control unit 32 determines whether the state of "yes" in step S102 and "no" in step S104 has lasted for a certain period of time (e.g., 1 day or 2 days).

[0042] If the state of "yes" in step S102 and "no" in step S104 does not last for a certain period of time (step S110: no), then the device control unit 32 retains the determination that the heating of the terminal fitting 14 is caused by the abnormality of the terminal metal fitting 14, and returns to step S101 and continues to monitor the temperature data.

[0043] Afterwards, if the state of "yes" in step S102 and "no" in step S104 continues for a certain period of time (step S110: yes), then the device control unit 32 determines that the heating of the terminal hardware 14 is caused by an abnormality (step S105), and sends a terminal hardware abnormality notification to the upper server 41 through the wireless communication unit 34 to notify the upper server 41 of the abnormality of the terminal hardware 14 (step S106).

[0044] According to Embodiment 2, since the condition for determining that the temperature rise inside the meter 11 is caused by an abnormality in the terminal fitting 14 has been added that the temperature rise is continuous, the determination accuracy will be improved compared to Embodiment 1.

[0045] In addition, the various embodiments can be freely combined, and appropriate modifications or omissions can be made to each embodiment.

[0046] It should be understood that all the states described above are merely illustrative, and variations not illustrated can be conceived. [Simplified Explanation of the Diagram]

[0010] Figure 1 is a configuration diagram of the electricity meter in Embodiment 1. Figure 2 is a functional block diagram of the electricity meter in Embodiment 1. Figure 3 is a flowchart showing the process of determining whether the overheating of the electricity meter's terminal fittings (i.e., terminal metal accessories) is caused by an abnormality in the terminal fittings in Embodiment 1. Figure 4 is a flowchart showing the process of determining whether the overheating of the electricity meter's terminal fittings is caused by an abnormality in the terminal fittings in Embodiment 2.

Claims

1. An electricity meter, comprising: Terminal fittings for connecting power cords; The electricity metering unit calculates the consumer's electricity consumption based on the current and voltage values ​​of the front terminal fittings and outputs electricity data representing the aforementioned electricity consumption; the temperature detection unit outputs temperature data representing the internal temperature of the aforementioned electricity meter; and the judgment processing unit determines that the aforementioned terminal fittings are malfunctioning when the aforementioned temperature data exceeds a predetermined temperature threshold and the electricity data is equal to or less than a predetermined electricity threshold.

2. The electricity meter described in claim 1 further includes: The communication unit is configured to send a notification indicating the abnormality of the terminal fitting to the upper-level server when the aforementioned determination processing unit determines that the aforementioned terminal fitting is abnormal.

3. The electricity meter as described in request item 1 or 2, wherein, The aforementioned determination processing unit obtains ambient temperature data representing the ambient temperature of the area where the aforementioned electricity meter is installed, and subtracts the aforementioned ambient temperature data from the aforementioned temperature data, using the result as temperature data to compare with the aforementioned temperature threshold.

4. The electricity meter as described in request item 1 or 2, wherein, When the aforementioned temperature data exceeds the aforementioned temperature threshold and the aforementioned electrical quantity data is equal to or less than the aforementioned electrical quantity threshold for a certain period of time, the aforementioned determination and processing unit determines that the aforementioned terminal hardware has malfunctioned.

5. The electricity meter as described in request item 3, wherein, When the aforementioned temperature data exceeds the aforementioned temperature threshold and the aforementioned electrical data is equal to or less than the aforementioned electrical data for a certain period of time, the aforementioned determination processing unit determines that the terminal hardware has malfunctioned.

6. A method for detecting malfunctions in an electricity meter, comprising: The electricity metering unit calculates the consumer's electricity consumption based on the current and voltage values ​​of the meter's terminal fittings and outputs electricity consumption data; the temperature detection unit outputs temperature data indicating the internal temperature of the meter; when the temperature data exceeds a predetermined temperature threshold and the electricity consumption data is equal to or less than the predetermined electricity consumption threshold, the meter's determination processing unit determines that the terminal fittings are malfunctioning.

7. The method for detecting meter malfunctions as described in claim 6 further includes: When the aforementioned determination and processing unit determines that the aforementioned terminal hardware is abnormal, the aforementioned meter's communication unit will transmit a notification indicating that the aforementioned terminal hardware is abnormal to the upper-level server.

8. The method for detecting meter malfunctions as described in request item 6 or 7, wherein, The aforementioned determination processing unit obtains ambient temperature data representing the ambient temperature of the area where the aforementioned electricity meter is installed, and uses the result obtained by subtracting the aforementioned ambient temperature from the aforementioned temperature data as temperature data to compare with the aforementioned temperature threshold.

9. The method for detecting meter malfunctions as described in request item 6 or 7, wherein, When the aforementioned temperature data exceeds the aforementioned temperature threshold and the aforementioned electrical quantity data is equal to or less than the aforementioned electrical quantity threshold for a certain period of time, the aforementioned determination and processing unit determines that the aforementioned terminal hardware has malfunctioned.

10. The method for detecting meter malfunctions as described in claim 8, wherein, When the aforementioned temperature data exceeds the aforementioned temperature threshold and the aforementioned electrical data is equal to or less than the aforementioned electrical data for a certain period of time, the aforementioned determination processing unit determines that the terminal hardware has malfunctioned.

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