Power measurement system and active power measurement method in power measurement system

Abstract

This power measurement system comprises: an amplitude coefficient acquisition sensor (1A) that performs direct measurement from a conductor MLc or BLc in a power line ML or BL, and acquires an amplitude coefficient a based on data of a measured voltage amplitude; a non-contact type current sensor (20) that measures a current of a commercial power supply (9) supplied to a branch power line BL, without electrical contact with the conductor BLc in the branch power line BL being measured; a non-contact type voltage sensor (30) that measures a voltage of a commercial power source P supplied to the branch power line BL being measured, without electrical contact with the conductor BLc in the branch power line BL being measured; and a power calculation unit in a data processing and communication unit (40), the power calculation unit calculating active power on the basis of a calibrated voltage calculated from the voltage measured by the non-contact type voltage sensor (30) using the amplitude coefficient acquired by the amplitude coefficient acquisition sensor 1A, and the current measured by the non-contact type current sensor (20).

Description

Power measurement system and method for measuring active power in the power measurement system

[0001] The present disclosure relates to a power measurement system including a plurality of power sensor devices each having a non-contact current sensor and a non-contact voltage sensor, and configured to measure the active power of a commercial power source, and a method for measuring active power in the power measurement system.

[0002] When measuring the current and voltage of a power line, a non-contact sensor is required to avoid and prevent serious accidents such as short circuits and electric shock. A non-contact current sensor using a clamp-type probe is known as a non-contact current sensor. Various non-contact voltage sensors have been studied, and one example is shown in Patent Document 1.

[0003] The contents of Patent Document 1 are as follows: Power line sensors are arranged on each phase of a medium-voltage three-phase power supply line (power line), and each power line sensor includes a sensor plate at the bottom of the main body and a detection circuit. The detection circuit measures the extremely small current that flows back and forth between the power line and the surface of the sensor due to the capacitive impedance C0 between the sensor plate and the ground surface, and transmits the detected voltage to a data collection device. The data collection device uses the voltage detected by the power line sensor as a substitute voltage measurement value.

[0004] For each phase, a calibration process for the power line sensor voltage measurements is performed in the field using a high-speed, shafted setup device (calibration device). The calibration process for each phase power line sensor obtains and determines calibration coefficients for the sensor's phase voltages by comparing the power line sensor voltage measurements with phase-to-neutral voltage measurements by the time-synchronized setup device. When the power line sensor is in use, an automatic setup process is used to generate alternative voltage measurements for each phase by changing the magnitude of the power line sensor's sensed voltage to match the phase-to-neutral voltage measurements by the setup device.

[0005] Special table 2017-516983 publication

[0006] When measuring the voltage of a power line without contact, a calibration process for the voltage measurement value is required, and in Patent Document 1, a setup device is provided separately from the power line sensor. Meanwhile, in a power measurement system that measures the power consumption (active power) of a commercial power source (50 Hz, 60 Hz) in a power distribution system such as a building or factory, a power sensor device (slave) is installed for each of a plurality of branch power lines branching off from a main power line.

[0007] In a power sensor device, when a power line arrangement sensor and a setup device as shown in Patent Document 1 are applied as a non-contact voltage sensor, the power sensor device installed for each of the multiple branch power lines must be equipped with a setup device, which increases the size of the power sensor device and leads to an increase in the number of devices that make up the power measurement system.

[0008] The present disclosure has been made in consideration of the above points, and aims to provide a power measurement system that is equipped with a non-contact current sensor and a non-contact voltage sensor as power sensor devices installed on each of a plurality of branch power lines, and that can be made compact.

[0009] The power measurement system according to the present disclosure includes an amplitude coefficient acquisition sensor that receives and measures the voltage of commercial power supplied to a power line having a conductor and an insulator covering the conductor directly from the conductor in the power line and acquires an amplitude coefficient based on data on the measured voltage amplitude; non-contact current sensors that measure the current of commercial power supplied to different branch power lines, each having a conductor and an insulator covering the conductor, without electrically contacting the conductor in the branch power line being measured; non-contact voltage sensors that measure the voltage of commercial power supplied to the branch power line being measured, without electrically contacting the conductor in the branch power line being measured; and a plurality of power sensor devices having a power calculation unit that calculates active power from a calibrated voltage calculated using the voltage measured by the non-contact voltage sensor and an amplitude coefficient acquired by the amplitude coefficient acquisition sensor, and a current measured by the non-contact current sensor.

[0010] According to the present disclosure, serious accidents such as short circuits and electric shocks can be avoided and prevented when measuring the active power of each of a plurality of branch power lines, and each of a plurality of power sensor devices can be made smaller.

[0011] FIG. 1 is a schematic diagram showing an example of the configuration of a power measurement system according to embodiment 1. FIG. 2 is a block diagram showing an example of the internal configuration of a contact voltage sensor of a power sensor device in the power measurement system according to embodiment 1. FIG. 3 is a block diagram showing an example of the configuration of a power sensor device in the contact power measurement system according to embodiment 1. FIG. 4 is a block diagram showing an example of the internal configuration of a non-contact voltage sensor of a power sensor device in the contact power measurement system according to embodiment 1. FIG. 5 is a diagram showing one cycle of current waveforms and voltage waveforms in a branch power line measured by a non-contact current sensor and a non-contact voltage sensor in a power sensor device in the non-contact power measurement system according to embodiment 1. FIG. 6 is a flowchart showing a method of measuring the active power of a commercial power supply supplied to a branch power line in the non-contact power measurement system according to embodiment 1.

[0012] Embodiment 1. A power measurement system according to embodiment 1 will be described with reference to Figures 1 to 5. The power measurement system according to embodiment 1 is a power measurement system that measures the power consumption (active power) of a commercial power supply (50 Hz, 60 Hz) in a power distribution system of, for example, a building or a factory building. When measuring active power, it is necessary to measure not only the current value but also the voltage value, which varies from the specified voltage value of the commercial power supply, so that accurate calculation of active power requires measurement of the voltage value.

[0013] The power measurement system according to the first embodiment includes a plurality of branch power lines BL branched from a main power line ML. １ , B.L. ２ , B.L. ３ , ... and each of them receives commercial power P from the power receiving device R １１ , R １２ , ..., R ２１ , R ２２ , ..., R ３１ , ... in a power distribution system supplying a plurality of branch power lines BL １ , B.L. ２ , B.L. ３, ... power receiving device R that receives commercial power A from each １１ , R １２ , ..., R ２１ , R ２２ , ..., R ３１ , . . . is a power measurement system that accurately measures the active power consumed by

[0014] Power receiving device R １１ , R １２ , ..., R ２１ , R ２２ , ..., R ３１ , ... are devices whose power consumption you want to measure. The main power line ML is the conductor ML ｃ and conductor ML ｃ Insulator ML covering Ｉ A cable having a plurality of branch power lines BL １ , B.L. ２ , B.L. ３ , ...each is a conductor BL that serves as a core wire Ｃ and conductor BL Ｃ Insulator BL covering Ｉ It is a cable having the following.

[0015] The power measurement system according to the first embodiment includes a plurality of branch power lines BL. １ , B.L. ２ , B.L. ３ , ... the current in each of the branch power lines BL is measured by the non-contact current sensor 20, and the voltage is measured by the non-contact voltage sensor 30. １ , B.L. ２ , B.L. ３ , ... is a power measurement system that measures the power of a commercial power source P in each of the following locations. １ , B.L. ２ , B.L. ３ , ... are installed within a practical distance range, and a main power line ML and a plurality of branch power lines BL １ , B.L. ２ , B.L. ３ , ..., the same voltage waveform is obtained regardless of the position of the power line.

[0016] In FIG. 1, the power receiving device R １１ , R １２ , ... are branch power lines BL １ A commercial power source P is supplied from the branch power line BL １ By measuring the current and voltage values ​​in the power receiving device R １１ , R １２ , ... can measure the active power consumed by the power receiving device R ２１ , R ２２ , ... are branch power lines BL ２ A commercial power source P is supplied from the branch power line BL ２ By measuring the current and voltage values ​​in the power receiving device R ２１ , R ２２ , ... can measure the active power consumed by the power receiving device R ３１ , ... are branch power lines BL ３ A commercial power source P is supplied from the branch power line BL ３ By measuring the current and voltage values ​​in the power receiving device R ３１ ...the active power consumed can be measured.

[0017] As shown in FIG. 1, the power measurement system according to the first embodiment includes a data collection device (parent device) 1 and a power sensor device (child device) 2. １ , 2 ２ , 2 ３ , .... The data collection device 1 is installed on the main power line ML. The power sensor device 2 １ , 2 ２ , 2 ３ , ... are branch power lines BL １ , B.L. ２ , B.L. ３ , ... are installed in a one-to-one relationship with each other.

[0018] The data collection device 1 is a power sensor device 2 １ , 2 ２ , 2 ３ , ... and relays it to the host system. １ , 2 ２ , 2 ３, . . . are performed by, for example, the commonly known short-range wireless communication.

[0019] The data collection device 1 includes an amplitude coefficient acquisition sensor 1A and a data processing and communication unit 1B. The amplitude coefficient acquisition sensor 1A measures the voltage of the power from a commercial power source P supplied to a main power line ML by measuring the voltage of the conductor ML in the main power line ML. ｃ The amplitude coefficient acquisition sensor 1A receives and measures the voltage directly from the contact-type voltage sensor 10a and acquires an amplitude coefficient a based on the measured voltage value (voltage amplitude) data. The amplitude coefficient acquisition sensor 1A includes a contact-type voltage sensor 10a and an amplitude coefficient calculation unit 10b.

[0020] The contact type voltage sensor 10a is connected to a conductor ML in the main power line ML. ｃ and conductor ML ｃ The contact voltage sensor 10a has a probe electrode 11, a sensor section 12, and a probe cable 13, as shown in FIG.

[0021] The probe electrode 11 is a conductor ML in the main power line ML. ｃ In the first embodiment, the probe electrode 11 is a power plug that is inserted into a power outlet connected to the main power line ML. By adopting a configuration in which the power plug is inserted into a power outlet connected to the main power line ML, a safe electrode connection (contact measurement) can be achieved.

[0022] The sensor unit 12 digitizes the voltage waveform detected by the probe electrode 11 into voltage data. The sensor unit 12 has a gain capacitor 12 a, an amplifier element 12 b, and an analog-to-digital (AD) converter 12 c. One electrode of the gain capacitor 12 a is electrically connected to the probe electrode 11 via a probe cable 13.

[0023] The amplifier element 12b is an operational amplifier having a non-inverting input terminal (+), an inverting input terminal (-), and one output terminal, with a negative feedback circuit connected between the output terminal and the inverting input terminal. The negative feedback circuit is a parallel circuit of a resistor and a capacitor. The inverting input terminal of the amplifier element 12b is electrically connected to the other electrode of the gain capacitor 12a. The non-inverting input terminal of the amplifier element 12b is grounded.

[0024] The AD converter 12c converts into digital data the output from the amplifier element 12b, i.e., the analog voltage obtained by amplifying the voltage detected by the probe electrode 11. The digital data converted by the AD converter 12c corresponds to the voltage value on the main power line ML to which power is supplied from the commercial power source P.

[0025] The amplitude coefficient calculation unit 10b calculates an amplitude coefficient a, which is the ratio of the voltage value (voltage amplitude) on the main power line ML measured by the contact voltage sensor 10a to the specified voltage value (voltage amplitude) of the commercial power source P. The specified voltage value of the commercial power source P is an effective voltage of 100 V and a peak voltage of 141 V. For example, if the voltage value on the main power line ML measured by the contact voltage sensor 10a is 98 V, the amplitude coefficient a is 0.98 (= 98 / 100). The hardware configuration of the amplitude coefficient calculation unit 10b is a microcomputer or the like.

[0026] The voltage value on the main power line ML measured by the contact voltage sensor 10a may not be the specified voltage value of the commercial power supply P due to fluctuations in power consumption in the power transmission and distribution systems. The fluctuations in the voltage value are, for example, from a few percent to 10% or less.

[0027] In addition, the power receiving device R １１ , R １２ , ..., R ２１ , R ２２ , ..., R ３１ , ..., nonlinear distortion or pulse noise may occur in the voltage waveform, which is essentially a sine wave, and as a result, the voltage value on the main power line ML measured by contact voltage sensor 10a may not be the specified voltage value of the commercial power supply P. Note that while a commercial power supply P with a specified voltage value of an effective voltage of 100 V will be described, the same applies to a commercial power supply P with a specified voltage value of an effective voltage of 200 V.

[0028] The data processing and communication unit 1B instructs the amplitude coefficient calculation unit 10b on the timing of acquiring the amplitude coefficient a, stores the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b, and transmits the amplitude coefficient a to all the power sensor devices 2 via short-distance wireless communication. １ , 2２ , 2 ３ , .... The amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b is transmitted to all the power sensor devices 2 １ , 2 ２ , 2 ３ , . . . store the amplitude coefficient a transmitted from the data processing and communication unit 1B in the data collecting device 1.

[0029] That is, the data collection device 1 and all the power sensor devices 2 １ , 2 ２ , 2 ３ , ... share the same amplitude coefficient a. １ , 2 ２ , 2 ３ , ... by short-distance wireless communication, and the collected data is collected by the power sensor device 2 １ , 2 ２ , 2 ３ It also has the function of aggregating data from these and relaying it to a higher-level system.

[0030] Power sensor device 2 １ , 2 ２ , 2 ３ , ... each has a non-contact type current (I) sensor 20, a non-contact type voltage (V) sensor 30, and a data processing and communication unit 40. １ , 2 ２ , 2 ３ , ... respectively represent the data collection device 1 and all power sensor devices 2 １ , 2 ２ , 2 ３ , ..., the instantaneous voltage value measured by the non-contact voltage sensor 30 is converted into a corrected instantaneous voltage value (hereinafter referred to as instantaneous corrected voltage) based on the same amplitude coefficient a shared among the non-contact current sensors 20, and the active power is calculated using the instantaneous corrected voltage and the instantaneous current value measured by the non-contact current sensor 20. １ , 2 ２ , 2 ３ , ... have the same configuration, and therefore, in order to simplify the explanation, the subscripts will be omitted.

[0031] The non-contact current sensor 20 measures the current of the commercial power supply P supplied to the corresponding branch power line BL by measuring the conductor BL of the branch power line BL. Ｃ The non-contact current sensor 20 measures the current in a non-contact state. Ｃ 5 shows the current waveform and voltage waveform for one cycle in the branch power line BL measured by the non-contact current sensor 20 and the non-contact voltage sensor 30 when a commercial power source P (for example, 50 Hz) is supplied to the branch power line BL.

[0032] As an example, the current value measured by the non-contact current sensor 20 is input as instantaneous current values ​​ten times at equal intervals per cycle into the data processing and communication unit 40 under the control of the data processing and communication unit 40, as shown by black circles in Fig. 5. Although ten times is shown as an example, any number of times may be used.

[0033] The non-contact current sensor 20 is, for example, a non-contact current sensor that uses a clamp-type probe. As shown in Fig. 3, the non-contact current sensor 20 has a current clamp core 21, a sensor unit 22, and a probe cable 23. The current clamp core 21 is disposed so as to surround the branch power line BL, and detects the value of the current (current waveform) flowing through the branch power line BL.

[0034] The sensor unit 22 digitizes the current waveform detected by the current clamp core 21 into current data. The sensor unit 22 has an amplifier element 22a and an analog-to-digital (AD) converter 22b. The amplifier element 22a is an operational amplifier having a non-inverting input terminal (+), an inverting input terminal (-), and one output terminal, with a negative feedback circuit connected between the output terminal and the inverting input terminal. The negative feedback circuit is a parallel circuit of a resistor and a capacitor. The inverting input terminal and non-inverting input terminal of the amplifier element 22a are each electrically connected to the current clamp core 21 via a probe cable 23.

[0035] The AD converter 22b converts the output from the amplifying element 22a, that is, the analog voltage obtained by amplifying the current detected by the current clamp core 21, into digital data. The digital data converted by the AD converter 22b corresponds to the value of the current flowing through the branch power line BL to which power is supplied from the commercial power source P. The value of the current flowing through the branch power line BL detected by the sensor unit 22 is used by the data processing and communication unit 40 to calculate the active power in the branch power line BL.

[0036] The non-contact voltage sensor 30 measures the voltage of the commercial power supply P supplied to the corresponding branch power line BL by measuring the voltage of the conductor BL in the branch power line BL. Ｃ The non-contact voltage sensor 30 measures the voltage of the conductor BL in a non-contact state. Ｃ 5 as black circles, the voltage values ​​measured by the non-contact voltage sensor 30 are input into the data processing and communication unit 40 as instantaneous voltage values ​​ten times at equal intervals per cycle in synchronization with the input of the instantaneous current values ​​from the non-contact current sensor 20. Although ten times is shown as an example, any number of times may be used.

[0037] 3 and 4, the non-contact voltage sensor 30 has a probe electrode 31, a sensor unit 32, and a probe cable 33. The non-contact voltage sensor 30 is connected between the probe electrode 31 and the conductor BL of the branch power line BL. Ｃ By utilizing the minute coupling capacitance 50 that occurs between the conductor BL Ｃ The voltage value (voltage amplitude) at

[0038] The probe electrode 31 is connected to the insulator BL of the branch power line BL. Ｉ The insulator BL surrounds Ｉ As a result, the probe electrode 31 is placed in contact with the surface of the conductor BL of the branch power line BL. Ｃ By being disposed close to the probe electrode 31, the conductor BL of the branch power line BL Ｃ A coupling capacitance 50 occurs between them.

[0039] The probe electrode 31 is connected to the conductor BL via a coupling capacitance 50.Ｃ Without contacting the conductor BL Ｃ The voltage waveform at the probe electrode 31 and the conductor BL of the branch power line BL is detected. Ｃ The coupling capacitance 50 generated between the probe electrode 31 and the branch power line BL varies in capacitance depending on the amount of attachment of the probe electrode 31 to the branch power line BL.

[0040] Conductor BL using coupling capacitance 50 Ｃ The absolute value of the voltage amplitude in the conductor BL of the branch power line BL detected by the non-contact voltage sensor 30 is determined by using the amplitude coefficient a acquired by the amplitude coefficient acquisition sensor 1A in the data processing and communication unit 40. Ｃ A calibration process is performed on the voltage value at

[0041] The sensor unit 32 digitizes the voltage waveform detected by the probe electrode 31 into voltage data. The sensor unit 32 has an amplifier element 32a and an analog-to-digital (AD) converter 32b. The amplifier element 32a is an operational amplifier having a non-inverting input terminal (+), an inverting input terminal (-), and one output terminal, with a negative feedback circuit connected between the output terminal and the inverting input terminal.

[0042] The negative feedback circuit is a parallel combination of a resistor and a capacitor. The inverting input terminal of the amplifier element 32a is electrically connected to the probe electrode 31 via the probe cable 33. The non-inverting input terminal of the amplifier element 32a is grounded.

[0043] The AD converter 32b converts into digital data the output from the amplifier element 32a, i.e., the analog voltage obtained by amplifying the voltage detected by the probe electrode 31. The digital data converted by the AD converter 32b is the voltage value detected by the probe electrode 31 via the branch power line BL supplied with power from the commercial power source P.

[0044] The voltage value detected by the probe electrode 31 may not be a specified voltage value, or may be a voltage value in which nonlinear distortion or pulse noise occurs in the voltage waveform. ＣSince the detection is performed via the coupling capacitance 50 generated between the conductor BL of the branch power line BL Ｃ In order to obtain the voltage value at the branch power line BL, it is necessary to perform a calibration process on the voltage value detected by the probe electrode 31. The voltage value for the branch power line BL detected by the sensor unit 32 is used by the data processing and communication unit 40 to calculate the active power in the branch power line BL.

[0045] The data processing and communication unit 40 has a power calculation unit that performs data processing to obtain active power, and a data communication unit that transmits the active power data calculated by the power calculation unit to the data collection device 1 via short-range wireless communication.

[0046] The power calculation unit in the data processing and communication unit 40 calculates active power from the calibrated voltage calculated using the amplitude coefficient a acquired by the contact voltage sensor 10a and the voltage measured by the non-contact voltage sensor 30, and the current measured by the non-contact current sensor 20. The hardware configuration of the power calculation unit in the data processing and communication unit 40 is, for example, a microcomputer. The power calculation unit in the data processing and communication unit 40 simultaneously captures the voltage value measured by the non-contact voltage sensor 30 and the current value measured by the non-contact current sensor 20 as an instantaneous voltage value and an instantaneous current value.

[0047] In the following description, time t ｉ The instantaneous voltage value V measured at ｉ and the instantaneous current value I ｉ The following explanation will be given using the example where i is the time t ｉ From time t cycle In this example, it is an integer from 0 to 9.

[0048] The power calculation unit in the data processing and communication unit 40 has first to third functions. The first function is to calculate the instantaneous voltage value V ｉ The instantaneous corrected voltage (absolute value) V corrected by the amplitude coefficient a ｉ_ｃｏｒｒ This is a function that calculates the

[0049] The second function is to generate an instantaneous correction voltage V ｉ_ｃｏｒｒand an instantaneous current value I based on the current value measured by the non-contact current sensor 20 in synchronization with the time when the non-contact voltage sensor 30 measured the voltage value. ｉ The instantaneous power P ｉ The third function is to calculate the instantaneous power P ｉ In this example, the average value in one cycle is calculated and used as the active power P.

[0050] Time t in the first function ｉ Instantaneous correction voltage V ｉ_ｃｏｒｒ is calculated by the following formula (1).

[0051] In the above formula (1), Vpp is the peak voltage value of the voltage measured by the non-contact voltage sensor 30, and 141 is the peak voltage value at the specified voltage value of the commercial power supply P. That is, according to the above formula (1), Ｃ Even if the coupling capacitance 50 between the conductor BL and the branch power line BL is unknown, the capacitance value of the coupling capacitance 50 is not specified. Ｃ The voltage value at the instantaneous correction voltage V ｉ_ｃｏｒｒ Although the peak voltage value is used in the calculation, the effective voltage value may also be used.

[0052] Time t in the second function ｉ Instantaneous power P ｉ is calculated by the following equation (2).

[0053] In the third function, the active power P per cycle is calculated by the following equation (3).

[0054] In the above equation (3), Ecycle [·], which indicates the effective power P, is the expected value over one cycle (20 ms in the case of 50 Hz) of the commercial power supply P. For example, multiple (n) instantaneous powers P obtained in one cycle are expressed as ｉ In this first embodiment, n is 10.

[0055] In the power calculation section of the data processing and communication section 40, the instantaneous voltage value V measured by the non-contact voltage sensor 30 is ｉ The instantaneous correction voltage V calculated using the amplitude coefficient a ｉ_ｃｏｒｒ and the instantaneous current value I measured by the non-contact current sensor 20. ｉ The instantaneous power P ｉ Since the active power P is obtained by calculating the above, the active power value P in the branch power line BL can be obtained even if transient noise or distortion of the voltage waveform occurs in the branch power line BL.

[0056] Furthermore, since the non-contact voltage sensor 30 is used to measure the voltage value and the non-contact current sensor 20 is used to measure the current value when acquiring the active power value P in the branch power line BL, serious accidents such as short circuits and electric shocks can be avoided or prevented when acquiring the active power value P in the branch power line BL. The data communication unit in the data processing and communication unit 40 transmits the data of the active power P calculated by the power calculation unit in the data processing and communication unit 40 to the data collection device 1 via short-range wireless communication.

[0057] Next, a method for measuring the active power of the commercial power source P supplied to the branch power line BL using the non-contact type current sensor 20 and the non-contact type voltage sensor 30 included in the power sensor device 2 in the power measurement system according to the first embodiment will be described with reference to FIG. 6. In step ST1, the amplitude coefficient acquisition sensor 1A mounted on the data collection device 1 measures the active power of the conductor ML. ｃ and conductor ML ｃ Insulator ML covering Ｉ The voltage of the power of the commercial power source P supplied to the main power line ML having the conductor ML in the main power line ML is ｃ The voltage is directly received and measured, and an amplitude coefficient a is obtained based on the measured voltage amplitude data. Step ST1 is an amplitude coefficient obtaining step.

[0058] In step ST2, the non-contact current sensor 20 detects the conductor BL Ｃ and conductor BL Ｃ Insulator BL covering Ｉ The current of the power of the commercial power source P supplied to the branch power line BL having the conductor BL in the branch power line BL is measured.Ｃ The measurement is performed in a non-contact state. Step ST2 is a current measurement step.

[0059] In step ST3, the non-contact voltage sensor 30 detects the conductor BL Ｃ and conductor BL Ｃ Insulator BL covering Ｉ The voltage of the power from the commercial power source P supplied to the branch power line BL having the conductor BL in the branch power line BL to be measured is Ｃ The voltage is measured in a non-contact manner. Step ST3 is a voltage measurement step.

[0060] In step ST4, the power calculation unit in the data processing and communication unit 40 of the power sensor device 2 calculates active power from the current value of the commercial power supply P measured in step ST2 and the calibrated voltage value calculated by applying the amplitude coefficient a to the voltage value of the commercial power supply P measured in step ST3 at the same timing as the current value of the commercial power supply. Step ST4 is an active power calculation step.

[0061] In step ST4, the amplitude coefficient a is used to calculate the voltage value measured by the non-contact voltage sensor 30 at time t ｉ Instantaneous correction voltage V ｉ_ｃｏｒｒ and calculating at time t ｉ Instantaneous correction voltage V ｉ_ｃｏｒｒ and the time t ｉ Instantaneous current value I ｉ Using the above equation (2), the instantaneous power P ｉ and calculating all the instantaneous powers P calculated in one cycle. ｉ The method includes a step of calculating the effective power P per cycle by the above equation (3) using

[0062] The power measurement system according to the first embodiment measures the voltage of the power of the commercial power source P supplied to the power line ML or BL by measuring the voltage of the conductor ML in the power line ML or BL. ｃ or BL ｃand an amplitude coefficient acquisition sensor 1A that directly receives and measures the voltage amplitude from the conductor BL of the branch power line BL and acquires an amplitude coefficient a based on the measured voltage amplitude data. ｃ The non-contact current sensor 20 measures the voltage of the power of the commercial power source P supplied to the branch power line BL to be measured in an electrically non-contact state, and the voltage of the power of the commercial power source P supplied to the branch power line BL to be measured is measured by the conductor BL of the branch power line BL to be measured. ｃ The power sensor device 2 includes a non-contact voltage sensor 30 that measures in an electrically non-contact state, and a power calculation unit in a data processing and communication unit 40 that calculates effective power using a calibrated voltage calculated using the voltage measured by the non-contact voltage sensor 30 and an amplitude coefficient acquired by an amplitude coefficient acquisition sensor 1A, and a current measured by a non-contact current sensor 20.

[0063] As a result, serious accidents such as short circuits and electric shocks can be avoided and prevented when obtaining the active power value P in the branch power line BL, and the active power value P in the branch power line BL, i.e., the active power consumed by the power receiving device R supplied with commercial power P from the branch power line BL, can be measured with high accuracy.

[0064] In addition, for all of the power sensor devices 2, in order to calibrate the voltage values ​​measured by the non-contact voltage sensors 30, the probe electrodes 31 and the conductors BL in the branch power lines BL are connected to each other. Ｃ Without specifying the capacitance value of the coupling capacitance 50 occurring between the conductor BL of the branch power line BL Ｃ This makes it possible to reduce the size of each power sensor device 2 and to prevent the power measurement system from becoming too large.

[0065] In the power measurement system according to the first embodiment, the calculation of the effective power P in the power calculation unit of the power sensor device 2 is performed based on the instantaneous voltage value V at the voltage value V measured by the non-contact voltage sensor 30. ｉ The instantaneous corrected voltage V is corrected by the amplitude coefficient a. ｉ_ｃｏｒｒ Calculate the instantaneous correction voltage V ｉ_ｃｏｒｒ and instantaneous correction voltage V ｉ_ｃｏｒｒ The instantaneous current value I at the current value I measured by the non-contact current sensor 20 synchronized with the measurement time forｉ The instantaneous power P ｉ The calculated instantaneous power P ｉ As a result, even if transient noise or distortion of the voltage waveform occurs in the branch power line BL, a highly accurate active power value P can be obtained in the branch power line BL.

[0066] In the power measurement system according to the first embodiment described above, the amplitude coefficient acquisition sensor 1A is mounted on the data collection device 1, but the amplitude coefficient acquisition sensor 1A may be mounted on any one of the plurality of power sensor devices 2. When the amplitude coefficient acquisition sensor 1A is mounted on one power sensor device 2, the probe electrode 11 of the amplitude coefficient acquisition sensor 1A is a power plug that is inserted into an outlet connected to the branch power line BL.

[0067] In addition, in the power sensor device 2 equipped with the amplitude coefficient acquisition sensor 1A, the data communication unit in the data processing and communication unit 40 instructs the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A on the timing to acquire the amplitude coefficient a, stores the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A, and transmits the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b to all other power sensor devices 2 and the data collection device 1 via short-range wireless communication.

[0068] All other power sensor devices 2 and the data collecting device 1 store the amplitude coefficient a transmitted from the data communication unit in the data processing and communication unit 40 of the power sensor device 2 in which the amplitude coefficient acquisition sensor 1A is implemented. As a result, the data collecting device 1 and all power sensor devices 2 share the same value of the amplitude coefficient a.

[0069] Embodiment 2. The power measurement system according to embodiment 2 differs from the power measurement system according to embodiment 1 in that a function is added to the data processing and communication unit 1B to periodically acquire the amplitude coefficient a at a fixed time interval as the timing for acquiring the amplitude coefficient a for the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A, but is otherwise the same.

[0070] The components of the power measurement system according to the second embodiment are substantially the same as those of the power measurement system according to the first embodiment shown in Figures 1 to 4, and therefore the following description will focus on the amplitude coefficient acquisition sensor 1A and the data processing and communication unit 1B. The data processing and communication unit 1B provides a command signal indicating the timing for periodically acquiring the amplitude coefficient a at a fixed time interval to the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A. In the second embodiment, the fixed time interval is, for example, one second or one minute.

[0071] The amplitude coefficient calculation unit 10b acquires the amplitude coefficient at the timing indicated by the command signal from the data processing and communication unit 1B. That is, the amplitude coefficient calculation unit 10b acquires the voltage value (voltage amplitude) on the main power line ML measured by the contact voltage sensor 10a at the timing indicated by the command signal from the data processing and communication unit 1B, and calculates an amplitude coefficient a, which is the ratio of the acquired voltage value (voltage amplitude) to the specified voltage value (voltage amplitude) of the commercial power source P.

[0072] The data processing and communication unit 1B updates the stored contents of the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b every time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, and transmits the updated amplitude coefficient a to all the power sensor devices 2 via short-range wireless communication. １ , 2 ２ , 2 ３ , ..., each time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the amplitude coefficient calculation unit 10b transmits the calculated amplitude coefficient a. Every time an amplitude coefficient a is transmitted from the data processing and communication unit 1B in the data collection device 1, all the power sensor devices 2 update their stored contents with the amplitude coefficient a transmitted from the data processing and communication unit 1B in the data collection device 1 and store the updated content.

[0073] The data collection device 1 and all power sensor devices 2 share the same updated amplitude coefficient a each time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a. In the power calculation unit in the data processing and communication unit 40 of each power sensor device 2, the instantaneous voltage value V ｉ The instantaneous corrected voltage (absolute value) V corrected by the amplitude coefficient a updated and stored ｉ_ｃｏｒｒCalculate.

[0074] In the power measurement system according to the second embodiment, the amplitude coefficient a is acquired periodically at regular time intervals by the amplitude coefficient acquisition sensor 1A, and the amplitude coefficient a is updated at regular time intervals. Therefore, in addition to having the same effect as the power measurement system according to the first embodiment, even if fluctuations occur in the effective voltage of the commercial power supply P depending on the amount of power consumed by the equipment or power receiving device R inside or outside the building or other surrounding environments, the system can accurately measure the active power consumed by the power receiving device R to which the commercial power supply P is supplied from the branch power line BL.

[0075] In the power measurement system according to the second embodiment described above, the amplitude coefficient acquisition sensor 1A may be implemented in any one of the multiple power sensor devices 2. In this case, in the selected power sensor device 2, the data communication unit in the data processing and communication unit 40 provides a command signal indicating the timing for periodically acquiring the amplitude coefficient a at a fixed time interval to the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A.

[0076] In addition, the data communication unit in the data processing and communication unit 40 updates the stored contents of the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b each time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, and transmits the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b to all other power sensor devices 2 and the data collection device 1 via short-range wireless communication each time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a.

[0077] Every time the amplitude coefficient a is transmitted from the data communication unit in the data processing and communication unit 40 of the power sensor device 2 in which the amplitude coefficient acquisition sensor 1A is implemented, all other power sensor devices 2 and the data collecting device 1 update and store the stored contents of the amplitude coefficient a transmitted from the data communication unit in the data processing and communication unit 40 of the power sensor device 2 in which the amplitude coefficient acquisition sensor 1A is implemented. As a result, every time the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the data collecting device 1 and all power sensor devices 2 share the same updated amplitude coefficient a.

[0078] Embodiment 3. The power measurement system according to embodiment 3 differs from the power measurement system according to embodiment 1 in that a function is added to the data processing and communication unit 1B to acquire the amplitude coefficient a for the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A when a transient abnormality is detected in the voltage waveform of the power of the commercial power source P supplied to the main power line ML, but is otherwise the same.

[0079] 1 to 4, the components of the power measurement system according to the third embodiment are substantially the same as those of the power measurement system according to the first embodiment shown in FIG. 1 to 4, and therefore the following description will focus on the amplitude coefficient acquisition sensor 1A and the data processing and communication unit 1B. When the data processing and communication unit 1B detects a transient abnormality in the voltage waveform of the power from the commercial power source P, it issues a command to the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A to acquire the amplitude coefficient a.

[0080] In the third embodiment, data processing and communication unit 1B constantly monitors the voltage value (voltage amplitude) on main power line ML measured by contact voltage sensor 10a, and when the amplitude of the measured voltage waveform shows nonlinear distortion or a waveform shape that transiently differs from a normal voltage waveform, it determines that a transient abnormality has occurred in the voltage waveform of power from commercial power source P and issues a command to amplitude coefficient calculation unit 10b to acquire amplitude coefficient a. When the amplitude of the voltage waveform on main power line ML measured by contact voltage sensor 10a stabilizes, data processing and communication unit 1B restores amplitude coefficient a to the preset amplitude coefficient a.

[0081] The amplitude coefficient calculation unit 10b acquires the amplitude coefficient at the timing indicated by the command signal from the data processing and communication unit 1B. That is, the amplitude coefficient calculation unit 10b acquires the voltage value (voltage amplitude) on the main power line ML measured by the contact voltage sensor 10a at the timing indicated by the command signal from the data processing and communication unit 1B, and calculates an amplitude coefficient a, which is the ratio of the acquired voltage value (voltage amplitude) to the specified voltage value (voltage amplitude) of the commercial power source P.

[0082] When the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the data processing and communication unit 1B updates the stored content of the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b, and transmits the amplitude coefficient a to all the power sensor devices 2 via short-range wireless communication. １ , 2 ２ , 2 ３ , ..., the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, and transmits the calculated amplitude coefficient a. When the amplitude coefficient a is transmitted from the data processing and communication unit 1B in the data collection device 1, all the power sensor devices 2 update their stored contents with the amplitude coefficient a transmitted from the data processing and communication unit 1B in the data collection device 1 and store the updated content.

[0083] When the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the data collection device 1 and all the power sensor devices 2 share the same updated amplitude coefficient a. In the power calculation unit in the data processing and communication unit 40 of each power sensor device 2, the instantaneous voltage value V based on the voltage value measured by the non-contact voltage sensor 30 is calculated. ｉ The instantaneous corrected voltage (absolute value) V corrected by the amplitude coefficient a updated and stored ｉ_ｃｏｒｒ Calculate.

[0084] In the power measurement system according to the third embodiment, the amplitude coefficient a is acquired by the amplitude coefficient acquisition sensor 1A when a transient abnormality is detected in the voltage waveform of the power from the commercial power source P, and the amplitude coefficient a is updated. Therefore, in addition to having the same effect as the power measurement system according to the first embodiment, the system can accurately measure the active power consumed by the power receiving device R to which the commercial power source P is supplied from the branch power line BL, even if a transient fluctuation occurs in the commercial power source P, such as nonlinear distortion in the amplitude of the voltage waveform on the main power line ML or a waveform shape that is transiently different from the normal voltage waveform, depending on the operating status of the power receiving device R inside or outside the building.

[0085] In the power measurement system according to the third embodiment described above, the amplitude coefficient acquisition sensor 1A may be mounted in any one of the plurality of power sensor devices 2. In this case, in the selected power sensor device 2, when a transient abnormality is detected in the voltage waveform of the power from the commercial power source P, the data communication unit in the data processing and communication unit 40 issues a command signal to acquire the amplitude coefficient a to the amplitude coefficient calculation unit 10b in the amplitude coefficient acquisition sensor 1A.

[0086] In addition, when the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the data communication unit in the data processing and communication unit 40 updates the stored contents of the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b, and when the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, transmits the amplitude coefficient a calculated by the amplitude coefficient calculation unit 10b to all other power sensor devices 2 and the data collection device 1 via short-range wireless communication.

[0087] When the amplitude coefficient a is transmitted from the data communication unit in the data processing and communication unit 40 of the power sensor device 2 in which the amplitude coefficient acquisition sensor 1A is implemented, all other power sensor devices 2 and the data collecting device 1 update and store the stored contents of the amplitude coefficient a transmitted from the data communication unit in the data processing and communication unit 40 of the power sensor device 2 in which the amplitude coefficient acquisition sensor 1A is implemented. As a result, when the amplitude coefficient calculation unit 10b calculates the amplitude coefficient a, the data collecting device 1 and all power sensor devices 2 share the updated amplitude coefficient a of the same value.

[0088] Furthermore, in the power measurement system according to the above-described embodiment 3, similar to the power measurement system according to the embodiment 2, a configuration may be added in which the acquisition of the amplitude coefficient a by the amplitude coefficient acquisition sensor 1A is performed periodically at regular time intervals, and the amplitude coefficient a is updated at regular time intervals.

[0089] It should be noted that the embodiments may be freely combined, any of the components of the embodiments may be modified, or any of the components of the embodiments may be omitted.

[0090] The power measurement system according to the present disclosure is suitable for use as a power measurement system that measures active power in each of a plurality of branch power lines in a power distribution system such as a building or factory building.

[0091] P Commercial power supply, ML Main power line, BL １ , B.L. ２ , B.L. ３ , ... Branch power line, 1 Data collection device (parent unit), 1A Amplitude coefficient acquisition sensor, 10a Contact type voltage sensor, 10b Amplitude coefficient calculation unit, 11 Probe electrode, 12 Sensor unit, 13 Probe cable, 1B Data processing and communication unit, 2 １ , 2 ２ , 2 ３ , ... Power sensor device (slave unit), 20 Non-contact current sensor, 21 Current clamp core, 22 Sensor unit, 23 Probe cable, 30 Non-contact voltage sensor, 31 Probe electrode, 32 Sensor unit, 40 Data processing and communication unit.

Claims

1. An amplitude coefficient acquisition sensor that directly receives and measures the voltage of commercial power supplied to a power line having a conductor and an insulator covering the conductor from the conductor in the power line, and acquires an amplitude coefficient based on the measured voltage amplitude data, The power sensor device comprises a plurality of power sensor devices having a power calculation unit that calculates active power using a calibrated voltage calculated using the amplitude coefficient acquired by the amplitude coefficient acquisition sensor and the current measured by the non-contact current sensor, each having a conductor and an insulator covering the conductor, respectively, and a power calculation unit that calculates active power using a calibrated voltage calculated using the amplitude coefficient acquired by the amplitude coefficient acquisition sensor and the current measured by the non-contact current sensor, respectively, and the voltage measured by the non-contact voltage sensor. The amplitude coefficient acquisition sensor is implemented in a data acquisition device installed on a main power line to which multiple branch power lines are connected. Power measurement system.

2. The acquisition of the amplitude coefficient by the amplitude coefficient acquisition sensor is performed periodically at regular time intervals. The amplitude coefficient used by the power calculation unit in the power sensor device is updated each time the amplitude coefficient is acquired by the amplitude coefficient acquisition sensor. The power measurement system according to claim 1.

3. The acquisition of the amplitude coefficient by the amplitude coefficient acquisition sensor is performed when a transient anomaly is detected in the voltage waveform of the commercial power supplied to the power line. The amplitude coefficient used by the power calculation unit in the power sensor device is updated with the amplitude coefficient acquired by the amplitude coefficient acquisition sensor. The power measurement system according to claim 1 or claim 2.

4. The amplitude coefficient acquisition sensor comprises a contact-type voltage sensor and an amplitude coefficient calculation unit. The aforementioned contact-type voltage sensor has a probe electrode directly connected to a power line, and a sensor unit connected to the probe electrode via a probe cable, which digitizes the voltage waveform detected by the probe electrode in the contact-type voltage sensor into voltage data. The acquisition of the amplitude coefficient in the amplitude coefficient acquisition sensor is performed by the amplitude coefficient calculation unit, which calculates the amplitude coefficient as the ratio of the voltage waveform detected by the probe electrode of the contact-type voltage sensor to the specified voltage value of the commercial power supply, and the voltage data digitized by the sensor unit of the contact-type voltage sensor. The power measurement system according to claim 1 or claim 2.

5. The non-contact voltage sensor in the power sensor device has a probe electrode positioned to surround the insulator of the branch power line to be measured, and a sensor unit connected to the probe electrode via a probe cable, which digitizes the voltage waveform in the conductor obtained by utilizing the coupling capacitance between the probe electrode of the non-contact voltage sensor and the conductor of the branch power line to be measured, into voltage data. The calculation of active power in the power calculation unit of the power sensor device involves calculating an instantaneous calibration voltage value by calibrating the voltage data, which represents the instantaneous voltage value obtained by the sensor unit of the non-contact type voltage sensor from the voltage waveform in the conductor of the branch power line to be measured, using the amplitude coefficient obtained by the amplitude coefficient acquisition sensor; calculating an instantaneous active power value using the calculated instantaneous calibration voltage value and the digitized instantaneous current value in the conductor of the branch power line measured by the non-contact type current sensor, which is measured in synchronization with the time when the voltage waveform in the conductor of the branch power line measured by the non-contact type voltage sensor that calculates the instantaneous calibration voltage value was measured; and calculating the calibration active power value of the active power in one cycle from the calculated instantaneous active power value. The power measurement system according to claim 1 or claim 2.

6. A method for measuring the active power of commercial power supplied to a power line using a non-contact current sensor and a non-contact voltage sensor of a power sensor device, wherein the amplitude coefficient acquisition sensor is implemented in a data acquisition device installed on a main power line to which multiple branch power lines are connected, The amplitude coefficient acquisition step involves the amplitude coefficient acquisition sensor directly receiving and measuring the voltage of the commercial power supplied to the power line having a conductor and an insulator covering the conductor from the conductor in the power line, and acquiring an amplitude coefficient based on the measured voltage amplitude data. The non-contact current sensor measures the current of the commercial power supplied to a power line having a conductor and an insulator covering the conductor, in a current measurement step in a state of non-electrical contact with the conductor in the power line to be measured. A voltage measurement step in which the voltage of the commercial power supplied to the power line to be measured by the non-contact type voltage sensor is measured in a state of electrical non-contact with the conductor in the power line to be measured. The power sensor device includes an active power calculation step which calculates active power using the current value of the commercial power supply measured in the current measurement step and a calibrated voltage value calculated using an amplitude coefficient on the voltage value of the commercial power supply measured at the same timing as the current value of the commercial power supply measured in the current measurement step, A method for measuring active power in a power measurement system equipped with the following features.