JP3561186B2 - Inductive watt-hour meter with average current measurement function - Google Patents

Description

これら各式において、回路の力率ｃｏｓφは１として簡易に計算される。
【００２５】
このようにして算出された積算使用電力量Ｗおよび平均電流値Ｉは、液晶表示器９に表示される。また、必要に応じて通信機能用Ｉ／Ｆ回路１０を介して外部機器へ通信され、外部機器で確認される。
【００２６】
本実施形態による誘導形電力量計によれば、従来の誘導形電力量計に電流計測カウンタ８を備え、一定時間ｔ毎に電気パルスｐを計数することで、被測定回路に流れる平均電流値Ｉを求めることができる。従って、被測定回路の平均電流値Ｉは誘導形電力量計単独で計測される。このため、従来のように専用の電流測定器を設置する必要が無くなり、安価に電流計測が行えるようになる。また、専用の電流測定器を必要としなければ、これを設置するスペースも必要としなくなり、設置機器は需要家家屋の壁面に電力量計単独でコンパクトに収まり、家屋の美観を損ねることもなくなる。
【００２７】
また、誘導形電力量計では被測定回路の回路電圧や力率を計測する手段を備えておらず、また、単相２線式以外の配電方式では、複数回路の合成による電力量パルスしか得られない。つまり、被測定回路が多相の場合には、回転子１の回転は、各相の電流コイルが合成して発生する磁束および各相の電圧コイルが合成して発生する磁束によって電磁誘導されるからである。しかし、上述した本実施形態のように、電流計測カウンタ８の計数値に基づき、式（１）〜（４）の演算式によって平均電流値Ｉを算出する構成にすると、精密な電流計測は行えないが、目安としての電流計測を安価に行えるようになる。
【００２８】
また、本実施形態では、被測定回路に平均して流れる電流値が一定時間毎に繰り返し算出されるため、被測定回路の平均電流値Ｉは一定時間毎にリアルタイムに把握される。しかし、本構成のように、一定時間ｔ毎に繰り返して平均電流値Ｉを算出する構成に必ずしもする必要はなく、一定時間ｔの間のみにおいて被測定回路に平均して流れる電流値Ｉを算出する構成としてもよい。この場合には被測定回路の平均電流値Ｉはリアルタイムに把握されないが、被測定回路の一定時間ｔにおける平均電流値Ｉを把握することは可能である。
【００２９】
【発明の効果】
以上説明したように本発明によれば、予め設定された一定時間の間に発生されたパルス数はパルス計数手段によって計数され、この計数値に基づき、電流演算手段は一定時間の間に被測定回路に平均して流れる電流値を算出する。従って、被測定回路の平均電流値は誘導形電力量計単独で計測される。このため、専用の電流測定器を設置する必要が無くなり、安価に電流計測が行え、また、専用の電流測定器を設置するスペースが不要になり、需要家家屋の美観を損ねることもなくなる。
【００３０】
また、被測定回路に平均して流れる電流値を一定時間毎に繰り返し算出する構成にすると、被測定回路の平均電流値は一定時間毎にリアルタイムに把握されるようになる。また、電流演算手段で所定の演算式によって平均電流値を算出する構成にすると、精密な電流計測は行えないが、目安としての電流計測を安価に行えるようになる。
【図面の簡単な説明】
【図１】本発明の一実施形態によるハイブリッド型の誘導形電力量計の構成の概略を示すブロック図である。
【図２】電流計測カウンタおよび電力量計測カウンタにおける計数機構を示すタイミングチャート図である。
【符号の説明】
１…回転子
２…信号円板
２ａ…信号円板２の羽部
２ｂ…信号円板２の切り欠き部
３…光結合素子
４…ＣＰＵ
５…電源回路
６…パルスＩ／Ｆ回路
７…電力量計測カウンタ
８…電流計測カウンタ
９…液晶表示器
１０…通信機能用Ｉ／Ｆ回路
１１…停電検出回路
１２…不揮発性メモリ
１３…保護回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inductive power amount that detects the power consumption of a circuit under measurement by a mechanical rotor, converts the detected power consumption into an electric pulse, and electronically calculates the power consumption of the circuit under test. About the total.
[0002]
[Prior art]
Conventionally, in this type of hybrid inductive watt-hour meter, the voltage of the circuit under test is detected by a voltage coil and the current of the circuit under test is detected by a current coil, and the voltage is induced by the electromagnetic field generated by the voltage coil and the current coil. And the mechanical rotor rotates. The rotation of the rotor is converted into electric pulses by an optical sensor, and the number of pulses is counted by an electronic circuit using a microcomputer. The number of electric pulses to be converted is the number of pulses according to the power consumption since the rotation speed of the rotor is in accordance with the power consumption of the circuit to be measured. Accordingly, the power consumption of the circuit under measurement is calculated as an integrated value from the integrated count value of the pulse number, and the calculated power amount is displayed on the liquid crystal display.
[0003]
[Problems to be solved by the invention]
However, the above-mentioned conventional inductive watt-hour meter is used for measuring only the electric energy, and cannot measure the current flowing through the circuit to be measured. Therefore, in order to measure the current, conventionally, a current measuring sensor such as a CT (current transformer) and a dedicated measuring device for visually displaying the current detected by the sensor are separately prepared, and these are used for power measurement. It is often installed in a meter to measure current.
[0004]
For this reason, when performing current measurement with a conventional inductive watt-hour meter, a space for installing a current measurement sensor and a dedicated measuring device is required separately from a space for installing a watt-hour meter. Since the inductive watt-hour meter is generally installed on the wall of a customer's house, it is difficult to secure a large equipment installation space on the wall of the customer's house. Also, if such equipment is installed on a wall of a customer house occupying a large space, the aesthetic appearance of the house will be impaired. Also, in order to maintain the aesthetics of the house, it is necessary to install equipment that takes into account the aesthetics on the wall.
[0005]
Also, when it is desired to simply measure the current flowing through the circuit under measurement as a guide, a measuring instrument similar to that for accurately measuring the current is installed, which increases the cost.
[0006]
[Means for Solving the Problems]
The present invention has been made to solve such a problem, and the magnetic flux generated by combining the current coils of each phase and the inter-phase magnetic flux according to the amount of electric power used by the circuit to be measured distributed by the polyphase distribution system. A rotor that is electromagnetically induced to rotate by a magnetic flux generated by the combination of the voltage coils, a pulse generator that generates a predetermined number of electric pulses per unit power consumption according to the rotation of the rotor, and a pulse generator. Means for calculating an integrated power amount of the circuit to be measured by integrating the number of pulses generated by the means. Pulse counting means for counting the number of pulses generated by the generating means, and current calculation for calculating a current value flowing through the circuit under test for a predetermined time based on the number of pulses counted by the pulse counting means Characterized by comprising a built-in and stage.
[0007]
In such a configuration, when power is consumed in the circuit under test distributed in the multi-phase distribution system, the magnetic flux generated by the combination of the current coils of each phase and the voltage coil between the phases are generated according to the amount of power. The rotor is rotated by electromagnetic induction by the magnetic flux generated by the combination, and the number of electric pulses corresponding to the power consumption is generated by the pulse generating means. The number of pulses is integrated by the power amount measuring means, and the integrated power consumption of the circuit to be measured is calculated from the integrated value. In addition, the number of pulses generated during a predetermined period of time is counted by the pulse counting unit, and based on the counted value, the current calculation unit averages a current value flowing through the circuit under measurement during the predetermined period of time. calculate. Therefore, the average current value of the circuit under measurement is measured by the inductive watt-hour meter alone.
[0008]
Further, according to the present invention, the pulse counting means counts the number of pulses generated by the pulse generating means at regular time intervals, and the current calculating means averages a current value flowing through the circuit under measurement at regular time intervals. It is characterized in that it is calculated.
[0009]
In such a configuration, the average value of the current flowing through the circuit to be measured is repeatedly calculated at regular intervals. Therefore, the average current value of the circuit to be measured is grasped in real time at regular intervals.
[0010]
Further, according to the present invention, the current calculation means determines the number of pulses counted by the pulse counting means as the circuit voltage of the circuit to be measured, the predetermined number of pulses generated per unit power consumption by the pulse generation means, and a predetermined time. The average current value flowing through the circuit to be measured is calculated by dividing by the product of the coefficient and the coefficient corresponding to the phase of the power distribution system to be distributed to the circuit to be measured.
[0011]
Inductive watt-hour meters do not have means for measuring the circuit voltage or power factor of the circuit under test, and for circuits under test distributed using the multi-phase power distribution method, the number corresponding to the combined power consumption of each phase However, if the average current value is calculated in this manner by the current calculation means, accurate current measurement cannot be performed, but current measurement can be performed as a guide.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of an inductive watt-hour meter with an average current measuring function according to the present invention will be described.
[0013]
FIG. 1 is a block diagram schematically showing a configuration of a hybrid inductive watt-hour meter according to the present embodiment.
[0014]
A hybrid inductive watt-hour meter detects a voltage and a current of a circuit under test of a customer, and generates an electric pulse corresponding to the amount of electric power used, and an electric pulse generated by the power detecting unit. And an arithmetic unit for calculating and processing the integrated power consumption and the average current value of the circuit to be measured based on the number.
[0015]
The power detection unit includes a rotator 1, a signal disk 2, and an optical coupling element 3 as main elements. The rotator 1 is guided by an electromagnetic field generated by a voltage coil and a current coil for detecting the voltage and current of the circuit under measurement, and rotates according to the amount of power used. The signal disk 2 is provided on a rotation shaft of the rotor 1 and rotates with the rotation of the rotor 1. The signal disk 2 has a wing portion 2a and a notch portion 2b. The optical coupling element 3 is configured by an optical sensor such as a photo interrupter, and is arranged so that the signal disk 2 rotating in the “U” -shaped valley passes therethrough.
[0016]
The optical coupling element 3 emits a light beam between the U-shaped valleys, and while the light ray is blocked by the wings 2a of the signal disk 2, the optical coupling element 3 outputs a low-level signal. I do. However, while the signal disk 2 rotates and the light beam crosses the notch 2b, the optical coupling element 3 outputs a high-level signal. Therefore, the optical coupling element 3 generates an electric pulse p according to the rotation of the signal disk 2. Since the rotation of the signal disk 2 is synchronized with the rotation of the rotor 1, the number of electric pulses p generated by the optical coupling element 3 is a number corresponding to the power consumption of the circuit under test. The number of electric pulses p generated by the optical coupling element 3 per unit power consumption becomes a predetermined number of pulses according to an instrument constant [pulse / kWh] preset for the inductive watt-hour meter.
[0017]
The arithmetic unit has a CPU (Central Processing Unit) 4 that performs a control operation according to a preset program. The CPU 4 operates by receiving power supply from the power supply circuit 5. The CPU 4 includes a pulse I / F (interface) circuit 6, a power measurement counter 7, a current measurement counter 8, a liquid crystal display 9, a communication function I / F circuit 10, a power failure detection circuit 11, and a non-volatile memory 12. Is connected. The power input terminal is connected to a protection circuit 13 for protecting an incoming abnormal voltage or the like due to lightning or the like.
[0018]
The integrated value of the electric pulse p input from the optical coupling element 3 via the pulse I / F circuit 6 is counted by the electric energy measurement counter 7. Further, the current measurement counter 8 constitutes a pulse counting unit that counts the electric pulse p input from the optical coupling element 3 via the pulse I / F circuit 6 at a predetermined time interval. The CPU 4 constitutes a current calculation means for calculating a value of a current flowing through the circuit under measurement for a certain period of time based on the number of pulses counted by the current measurement counter 8. The liquid crystal display 9 visually displays the integrated power consumption and the average current value of the circuit to be measured calculated by the CPU 4 based on the count values of the power amount measurement counter 7 and the current measurement counter 8. The communication function interface 10 sends the calculated integrated power consumption and average current value to the external device.
[0019]
Further, when the power failure is detected by the power failure detection circuit 11, the CPU 4 writes the count value of the power amount measurement counter 7 at that time into the nonvolatile memory 12. Therefore, even if a power failure occurs, the integrated power amount at the time of the power failure is stored and held in the nonvolatile memory 12 until the power is restored.
[0020]
FIG. 2 is a timing chart showing a counting mechanism in the electric energy measurement counter 7 and the current measurement counter 8.
[0021]
When the electric pulse p is generated as shown in FIG. 4B, the electric energy measurement counter 7 sets the count value to 1 each time an edge change of the electric pulse p is detected as shown in FIG. Count up to 2, 3, ... and increase the integrated value over time. The CPU 4 calculates an integrated power consumption W [kWh] based on the count value counted by the power measurement counter 7 and an instrument constant [pulse / kWh] preset for the inductive watt-hour meter.
[0022]
Also, the counting by the current measurement counter 8 is performed as shown in FIG. 3C at every predetermined time t, for example, every 30 [sec] shown in FIG. That is, the current measurement counter 8 counts up the count value to 1, 2, 3,..., N−1, n every time the edge change of the electric pulse p is detected during the first fixed time t. . Then, every time the edge change of the electric pulse p is detected during the next fixed time t, the count value is counted up to 1, 2, 3,..., K-1, k. Thereafter, the edge change of the number of electric pulses p input within that time is counted at regular time intervals t in the same manner.
[0023]
The CPU 4 calculates the number of power amount pulses from the count value of the current measurement counter 8 at each of the timings t1, t2,. Separately, it is stored in the memory. Then, the obtained power amount pulse number P [pulses] within the measurement time, the rated voltage V [V] of the circuit to be measured, the measurement time (constant time) t [h], and the instrument constant α [pulse / kWh] are obtained. The average current value I [A] of the circuit to be measured is calculated by substituting the following arithmetic expressions (1) to (4). The arithmetic expression (1) is used when the power distribution system of the circuit under measurement is a single-phase two-wire system, the arithmetic expression (2) is a single-phase three-wire system, the arithmetic expression (3) is a three-phase three-wire system, and an arithmetic expression (4) is used in the case of a three-phase four-wire system.
[0024]

In each of these equations, the power factor cos φ of the circuit is simply calculated as 1.
[0025]
The integrated power consumption W and average current value I thus calculated are displayed on the liquid crystal display 9. In addition, communication is performed with an external device via the communication function I / F circuit 10 as necessary, and the external device confirms the communication.
[0026]
According to the inductive watt-hour meter according to the present embodiment, the conventional inductive watt-hour meter is provided with the current measuring counter 8 and counts the electric pulse p at every predetermined time t, so that the average current value flowing through the circuit to be measured I can be obtained. Therefore, the average current value I of the circuit to be measured is measured by the inductive watt-hour meter alone. For this reason, it is not necessary to install a dedicated current measuring device unlike the related art, and current measurement can be performed at low cost. In addition, if a dedicated current measuring device is not required, a space for installing the current measuring device is not required, and the installed device is compactly fitted on the wall surface of the customer's house with the watt-hour meter alone, so that the appearance of the house is not spoiled.
[0027]
In addition, inductive watt-hour meters do not have means for measuring the circuit voltage or power factor of the circuit under test, and in power distribution systems other than the single-phase two-wire system, only electric energy pulses obtained by combining multiple circuits are obtained. I can't. That is, when the circuit to be measured has multiple phases, the rotation of the rotor 1 is electromagnetically induced by the magnetic flux generated by the combination of the current coils of each phase and the magnetic flux generated by the combination of the voltage coils of each phase. Because. However, when the average current value I is calculated based on the count values of the current measurement counter 8 using the arithmetic expressions of the equations (1) to (4) as in the above-described embodiment, accurate current measurement can be performed. However, current measurement as a guide can be performed at low cost.
[0028]
Further, in the present embodiment, the average value of the current flowing through the circuit under measurement is repeatedly calculated at regular intervals, so that the average current value I of the circuit under measurement is grasped in real time at regular intervals. However, it is not always necessary to adopt a configuration in which the average current value I is repeatedly calculated every predetermined time t as in the present configuration, and the current value I flowing through the circuit under measurement only during the predetermined time t is calculated. It is good also as a structure which performs. In this case, the average current value I of the circuit under test is not grasped in real time, but it is possible to grasp the average current value I of the circuit under test at a fixed time t.
[0029]
【The invention's effect】
As described above, according to the present invention, the number of pulses generated during a predetermined period of time is counted by the pulse counting unit. The average value of the current flowing through the circuit is calculated. Therefore, the average current value of the circuit under measurement is measured by the inductive watt-hour meter alone. For this reason, it is not necessary to install a dedicated current measuring device, and the current can be measured at low cost. Further, a space for installing the dedicated current measuring device is not required, and the aesthetic appearance of the customer house is not spoiled.
[0030]
Further, if the average current value flowing through the circuit under measurement is repeatedly calculated at regular time intervals, the average current value of the circuit under measurement can be grasped in real time at regular time intervals. In addition, when the average current value is calculated by a predetermined arithmetic expression by the current arithmetic means, accurate current measurement cannot be performed, but current measurement as a guide can be performed at low cost.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing a configuration of a hybrid inductive watt-hour meter according to an embodiment of the present invention.
FIG. 2 is a timing chart illustrating a counting mechanism in a current measurement counter and a power amount measurement counter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Signal disk 2a ... Wing part 2b of signal disk 2 ... Notch 3 of signal disk 2 ... Optical coupling element 4 ... CPU
5 power supply circuit 6 pulse I / F circuit 7 electric power measurement counter 8 current measurement counter 9 liquid crystal display 10 communication function I / F circuit 11 power failure detection circuit 12 nonvolatile memory 13 protection circuit

Claims (3)

According to the power consumption of the circuit to be measured distributed by the multi-phase power distribution method, the magnetic flux generated by combining the current coils of each phase and the magnetic flux generated by combining the voltage coils between each phase are electromagnetically induced to rotate. A rotor, pulse generating means for generating a predetermined number of electric pulses per unit power consumption according to the rotation of the rotor, and integrating the number of pulses generated by the pulse generating means to integrate the circuit to be measured. In an induction-type watt-hour meter comprising: a power-amount measuring unit for calculating the power amount,
A pulse counting unit for counting the number of pulses generated by the pulse generating unit during a predetermined period of time; and the circuit to be measured during the predetermined period of time based on the number of pulses counted by the pulse counting unit. An inductive watt-hour meter with an average current measuring function, which comprises a built-in current calculating means for calculating a current value flowing on average. The pulse counting means counts the number of pulses generated by the pulse generation means at each fixed time, and the current calculation means calculates a current value flowing on average to the circuit under measurement at each fixed time. The inductive watt-hour meter with an average current measuring function according to claim 1. The current calculation means, the number of pulses counted by said pulse counting means, wherein a predetermined number of pulses generated in the unit power usage per in the circuit voltage of the circuit under test wherein the pulse generating means and said predetermined time and said The average according to claim 1 or 2, wherein an average current value flowing through the circuit under test is calculated by dividing by a product of a coefficient corresponding to a phase of a power distribution method distributed to the circuit under test. Inductive watt-hour meter with current measurement function.

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