JP2011247901A - Watt-hour meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow powering and interruption for each load of a user.SOLUTION: A watt-hour meter comprises: system side terminals which are connected to a power distribution system and receive electric power supplied from the power distribution system; first load-side terminals which are connected with a first load for which interruption of power supply is acceptable, and supply the electric power received from the power distribution system to the first load; second load-side terminals which are connected with a second load for which interruption of power supply is not acceptable, and supply the electric power received from the power distribution system to the second load; a measuring electronic circuit which measures the amount of electric power used by the first and the second loads; an interruption signal receiving unit which receives an interruption signal indicating that the loads should be cut off via a communication line; and a circuit breaker which interrupts the power supply to the first load-side terminals when the interruption signal receiving unit receives the interruption signal.

Description

The present invention relates to a watt-hour meter that can be turned on and off for each load.

  In order to level the power used by the load, there is a method of providing cheaper power during the midnight hours. On the other hand, a load such as an electric water heater that operates in the midnight time zone is controlled to be input at a preset time by using a time switch or a microcomputer. Patent Document 1 discloses a watt-hour meter having a switch unit for stopping and restarting power supply.

JP 2006-170787 A

  In the future, if the demand for power during the midnight hours increases due to the spread of electric vehicles, it is expected that it will be necessary to adjust the load during the midnight hours according to the specifications of the power distribution equipment (transformer capacity and transmission capacity). However, in the watt-hour meter with a switch unit of Patent Document 1, there is no circuit that cuts off only a specific load, and it is difficult to perform load adjustment.

  This invention is made | formed in view of the said subject, The main objective is to enable insertion and interruption | blocking for every load of a consumer.

In order to achieve the above object, the present invention is a watt-hour meter, which is connected to a power distribution system, receives a power supplied from the power distribution system, and the power supply is allowed to be cut off. A load is connected and a first load side terminal that supplies power received from the power distribution system to the first load and a second load that is not allowed to interrupt power supply are connected and received from the power distribution system. The load should be cut off via a second load side terminal for supplying power to the second load, a measuring electronic circuit for measuring the amount of power used by the first and second loads, and a communication line. A cut-off signal receiving unit that receives a cut-off signal to the effect, and a breaker that cuts off power supply to the first load-side terminal when the cut-off signal receiving unit receives the cut-off signal. Features.
According to this configuration, since the power supply to the adjustable load (first load) is interrupted by the circuit breaker, the normal load (second load) that is not adjustable is always supplied with power. It does not interfere with the use of normal loads at home. According to this, the electric power company can perform load adjustment without causing inconvenience to the consumer.

  According to the present invention, it is possible to perform charging and closing for each load of a consumer.

It is a figure which shows the structure of the electric power load adjustment system. It is a figure which shows the structure and principle of a watt-hour meter, (a) shows the structure of a watt-hour meter 2, (b) shows the basic composition of an electronic watt-hour meter, (c) is a watt-hour meter. A block diagram is shown. It is a figure which shows the hardware constitutions of the electric power load adjustment apparatus. It is a figure which shows the structure of the data memorize | stored in the memory | storage part 45 of the electric power load adjusting apparatus 4, (a) shows the structure of the prediction electric energy data 45A, (b) shows the structure of the measurement electric energy data 45B, (C) shows the structure of the input list 45C. 4 is a flowchart showing processing of the power load adjustment device 4.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the power load adjustment system according to the embodiment of the present invention, a circuit capable of load adjustment is installed in the watt-hour meter separately from a normal load circuit, instead of a switching device that uniformly stops and starts power supply. Using that circuit, for example, only a 200 V load represented by an electric water heater or the like is turned on or off at any time. According to this, it is possible to adjust the turning on and off of a specific load.

≪System configuration and overview≫
FIG. 1 is a diagram illustrating a configuration of the power load adjustment system S. The load adjustment system S includes a power distribution system L <b> 1, a transformer 1, an electric wire L <b> 2, a watt hour meter 2, a load 3, and a power load adjustment device 4. The distribution system L1 transmits power from the substation and supplies power to the transformer 1 connected to each interconnection point. The transformer 1 is, for example, a pole transformer, is linked to the power distribution system L1, and steps down the power received from the linked power distribution system L1 to supply the power to the electric wire L2. The electric wire L <b> 2 is a lead-in line provided for each transformer 1, and distributes electric power to each load 3 in a customer's house in the jurisdiction area of the transformer 1.

  The watt-hour meter 2 is installed in each customer's house, is supplied to the load 3 from the electric wire L2, and measures the amount of power consumed, and in accordance with an instruction from the power load adjustment device 4 Shut off. Since the load 3 is installed in each customer's house, receives power supply through the electric wire L2 and the watt-hour meter 2, and does not know when it is used like lighting equipment or air conditioning equipment, It is known that it operates in the late-night time period, such as an electric water heater, etc., and can be adjusted to be switched on or off, such as an electric water heater.

  The power load adjusting device 4 is installed in an electric power company and can communicate with the transformer 1 and the watt hour meter 2 via a network (communication line). Get the measured power. Then, the watt hour meter 2 is instructed to turn on or off the adjustable load 3 so that the amount of power consumed by each consumer in the subordinate system of the transformer 1 is leveled. One power load adjusting device 4 may be installed for one transformer 1 and a plurality of watt-hour meters 2 of its subordinate system, or a plurality of transformers 1 and a subordinate system of each transformer 1. One power meter 2 may be installed. When targeting a plurality of transformers 1 and the like, the power load adjusting device 4 divides the data to be acquired and the processing thereof for each transformer 1.

<< Device configuration >>
FIG. 2 is a diagram showing the configuration and principle of the watt-hour meter 2. FIG. 2A shows the configuration of the watt-hour meter 2. The watt hour meter 2 includes a system side terminal 11 and a load side terminal 12 on the outside, and includes an opening / closing operation unit (breaker) 20 and a metering unit 30 inside.

  System side terminal 11 consists of system side terminals 111, 112, and 113 connected to electric wire L2. The load side terminal 12 includes load side terminals 121, 122, 123 and 124 to which the load 3 is connected. The load side terminals 121, 122, and 123 are connected to a normal load 3 </ b> A that uses the load wiring of the customer's house. A 100V load 3A is connected between the terminals 121-122 and 122-123, and a 200V load 3A is connected between the terminals 121-123. Between the load side terminals 121-124, a 200V load 3B that can be adjusted to be turned on or off is connected. The adjustable load 3B is, for example, an electric water heater or the like.

  The opening / closing operation unit 20 includes opening / closing switches SW 1, SW 2, and SW 3, and performs load adjustment in the following three modes in accordance with an opening / closing instruction from the power load adjustment device 4. That is, in the stop mode, all the open / close switches SW1, SW2, and SW3 are shut off (open). In the normal use mode, all the open / close switches SW1, SW2 and SW3 are turned on (closed). In the load adjustment mode, the on / off switches SW1 and SW2 are turned on and the on / off switch SW3 is shut off. Note that turning on and off the on / off switches SW1, SW2, and SW3 means turning on and off the load 3 connected to the load side terminals 121, 123, and 124 connected to the on / off switches SW1, SW2, and SW3, respectively. A cutoff signal receiving unit (not shown) receives an opening / closing instruction (shutoff signal) from the power load adjusting device 4, and the opening / closing switches SW1, SW2, and SW3 are turned on and off according to the opening / closing instruction.

  The weighing unit 30 includes a weighing electronic circuit 31, wirings W1 to W7, and current sensors CT1 to CT3. The weighing electronic circuit 31 measures a voltage value between the wirings W1, W2, and W3, acquires a current value from the current sensors CT1, CT2, and CT3, and calculates an electric energy from the measured voltage value and the acquired current value. . The wirings W1, W2, and W3 connect the system side terminals 111, 112, and 113 to the weighing electronic circuit 31, respectively. The wiring W4 connects the wiring W1 to the open / close switch SW2. The wiring W5 connects the wiring W2 to the load side terminal 122. The wiring W6 connects the wiring W3 to the open / close switch SW1. The wiring W7 connects the wiring W4 to the open / close switch SW3. The current sensors CT1, CT2, and CT3 are current transformers (CT: Current Transformer) that measure alternating current, and measure the currents of the wirings W4, W6, and W7, respectively.

It is possible to adjust the normal metering P1, which is the amount of power consumption of the load 3A in the normally on state connected between the load side terminals 121, 122 and 123, and the on / off state connected between the load side terminals 121 and 124. The load adjustment metric P2 that is the power consumption amount of the load 3B is calculated by the following equations 1 and 2.

Here, the measurement principle of the watt-hour meter will be described. The watt-hour meter is a measuring instrument that integrates the product of the instantaneous value v (t) of the load voltage of the distribution line and the instantaneous value i (t) of the current consumption. FIG. 2B shows a basic configuration of the electronic watt-hour meter. As shown in FIG. 2B, the instantaneous voltage v (t) and the instantaneous current i (t) are converted into signals proportional to v (t) × i (t) (instantaneous power) multiplied by the multiplier. Is done. Next, this signal is integrated and converted into a signal proportional to the electric energy, and the electric energy is integrated and displayed on the display. The electric energy P is shown by the following formula 3.

  FIG.2 (c) shows the block diagram of a watt-hour meter. A signal proportional to the load voltage is detected by PT (Potential Transformer), while a signal proportional to the current consumption is detected by CT (Current Transformer), and these two signals are supplied to a power-voltage (power-current) converter. send. Here, it is converted into a voltage (current) proportional to the product of voltage and current, that is, power, and then converted to a pulse frequency proportional to the amount of power by a voltage-frequency (current-frequency) converter. That is, the instantaneous power that is an analog amount is converted into the number of pulses that is proportional to the power amount that is a digital amount. As a result, the pulse constant of the output pulse from the integrator is represented by the number of pulses per unit electric energy, such as 1000 pulses / kWs. That is, in this case, one pulse per 1 Ws is output from the integrator. Since this pulse has a small “time width” of electric energy per pulse (1 Ws per pulse at 1000 pu1se / kWs), it is not possible to drive a register that records the electric energy in units of kWh with this pulse. Therefore, this pulse frequency is divided to an appropriate frequency by the frequency divider (the frequency is lowered and the time width of one pulse is increased), and is displayed by the display device. Note that the multiplication factor for conversion into the actual power amount in the register is set based on the frequency division number of the frequency divider.

  FIG. 3 is a diagram illustrating a hardware configuration of the power load adjusting device 4. The power load adjustment device 4 includes a communication unit 41, a display unit 42, an input unit 43, a processing unit 44, and a storage unit 45. The communication unit 41 is a part that communicates with the transformer 1 and each watt hour meter 2 via a communication line, and is realized by, for example, a NIC (Network Interface Card) or the like. The display unit 42 is a part that displays data according to an instruction from the processing unit 44, and is realized by, for example, a liquid crystal display (LCD). The input unit 43 is a part in which an operator inputs data (for example, data of a predicted value of power consumption for each customer and for each hour), and is realized by, for example, a keyboard or a mouse. The processing unit 44 exchanges data between the units and controls the entire power load adjusting device 4. A CPU (Central Processing Unit) executes a program stored in a predetermined memory. Realized. The storage unit 45 stores data from the processing unit 44 and reads the stored data, and is realized by, for example, a nonvolatile storage device such as a flash memory or a hard disk device.

<< Data structure >>
FIG. 4 is a diagram illustrating a configuration of data stored in the storage unit 45 of the power load adjustment device 4. FIG. 4A shows the configuration of the predicted power amount data 45A. The predicted power amount data 45A is a normal load that is predicted for each customer (subcontractor of a power usage contract) of a subordinate system of a certain transformer 1 in the midnight time zone (for example, 23:00 to 8:00 on the next day). It shows the amount of power used by 3A and adjustable load 3B, and consists of a record for each customer including customer ID 45A1, predicted power amount 45A2, and total value 45A3. The consumer ID 45A1 is identification information unique to the consumer and may be identification information of a power usage contract, but is information corresponding to the normal load 3A and the adjustable load 3B in the consumer's house. Therefore, the customer ID 45A1 may be substituted with identification information unique to the load 3B. The same applies to customer IDs 45B1 and 45C1. The predicted power amount 45A2 indicates the power amount predicted for the normal load 3A and the adjustable load 3B between 23:00 and 8:00 on the next day, and includes a normal load component 45A21 and an adjustable load component 45A22. The total value 45A3 of the predicted power amount indicates the total value of the predicted power amount between 23:00 and 8:00 on the next day. In the last previous record, the total value of the predicted power amount 45A2 in the midnight time zone is set, and in the last record, the average value of the predicted power amount per unit time (30 minutes) is set.

  In addition, about the method of estimating the power consumption for every transformer, for example, Unexamined-Japanese-Patent No. 2006-352996 WHEREIN: As a transformer load assumption method, the measurement consumer with daily load measurement data and the non-measurement consumer without In a distribution system that includes both non-measurement consumers and measurement consumers, based on the annual fluctuations in past monthly power consumption, the daily load measurement of measurement consumers that is assumed to be similar to each non-measurement consumer The data is specified, and the daily load based on the specified daily load measurement data is obtained for the non-measurement consumer, and the daily load based on the daily load measurement data is obtained for the measurement consumer, and the power supply destination is determined for each transformer. The method of calculating | requiring the daily load according to a transformer by integrating the daily load about the said consumer is disclosed.

  FIG. 4B shows the configuration of the measured power amount data 45B. The measured power amount data 45B indicates the amount of power used by the adjustable load 3B, which is measured for each time of the consumers of the subordinate system of a certain transformer 1, and the consumer ID 45B1 and the measured power amount for each hour. It consists of records for each customer including 45B2, total value 45B3 of measured electric energy, and achievement rate 45B4. The customer ID 45B1 is identification information unique to the customer. The measured power amount 45B2 for each hour is a value obtained by actually measuring the power amount for a predetermined 30 minutes. The total value 45B3 of the measured power amount is a value obtained by totaling the measured power amount 45B2 for each hour for each day. The achievement rate 45B4 indicates the ratio of the total value 45B3 of the measured power amount to the adjustable load 45A22 in the predicted power amount 45A2. At this time, the total value 45B3 and the achievement rate 45B4 are updated each time the measured power amount 45B2 for each hour is updated.

  FIG. 4C shows the configuration of the input list 45C. The input list 45C indicates the order of the customer ID 45C1 of a subordinate system of a certain transformer 1 for each 30-minute time zone, and is referred to when instructing to input and shut off the load 3B. The customer IDs 45C1 are sorted in advance in descending order of the predicted electric energy 45A2, and are sorted in descending order of the achievement rate 45B3 after the time period has elapsed.

≪System processing≫
FIG. 5 is a flowchart showing processing of the power load adjustment device 4. In this process, the adjustable load 3B is sequentially turned on and off in the midnight time zone. As an idea of the processing, at the beginning of the midnight time zone, the load 3B is likely to use a lot of power based on the predicted power amount. Thereafter, the load 3B having a low achievement rate, which is a ratio of the actual measured power amount to the predicted power amount, is not reached the predicted power amount and is considered to have room for using more power. The load 3B having a high achievement rate exceeds the predicted power amount and is considered to be already using the power sufficiently, and therefore is cut off.

  First, the power load adjustment device 4 predicts the amount of power in bank units in advance (S501). The bank unit means that the load 3 of each customer's house in the subordinate system of the transformer 1 is a target, and the load 3B in the load 3 and the load 3B that can be adjusted to be turned on / off are Predict the amount of electricity for each customer. As a result, the predicted power amount 45A2 of each customer ID 45A1 is set in the predicted power amount data 45A of the storage unit 45. For the prediction method, see, for example, Japanese Patent Application Laid-Open No. 2006-352996.

  Next, the power load adjusting device 4 calculates a total 45A3 of the predicted power amounts 45A2 of the respective customer IDs 45A1, and calculates an average value per unit time based on the total 45A3 (S502). As a result, the average value (last record) of the predicted power amount 45A3 is set in the predicted power amount data 45A of the storage unit 45.

  Then, the power load adjustment device 4 performs initial setting of the input list 45C in the storage unit 45 (S503). That is, the customer IDs 45C1 are arranged in the descending order of the predicted power amount data 45A (that is, the order of the consumers who use a lot of power in the midnight time zone from usual). This is because the load 3B having the large predicted power amount data 45A is given priority. With the above, preparations are made before entering the midnight time zone.

  Subsequently, when entering the midnight time zone from 23:00 to 8:00 on the next day, the processing of S505 to S517 is repeated every 30 minutes set in advance (S504 to S518).

  First, the power load adjusting device 4 determines whether or not the elapsed time t = 0 (S505). The elapsed time t is an elapsed time from 23:00. Since t = 0 at first (Yes in S505), the process of S509 is executed. Since t> 0 after the second time (No in S505), the measurement data is collected from the watt-hour meter 2 through the communication line (S506). As a result, the measured power amount 45B2 of each customer ID 45B1 is set in the measured power amount data 45B of the storage unit 45. Subsequently, the achievement rate of the adjustable load 3B is calculated (S507). The achievement rate is calculated by dividing the total value 45B3 of the measured power amount by the adjustable load 45A22 in the predicted power amount 45A2, and is set to the achievement rate 45B4. Then, in the input list 45C of the storage unit 45, the customer IDs 45C1 in the time period are rearranged in ascending order of the achievement rate 45B4 (S508). This is suitable for giving priority to the load 3B having a low achievement rate 45B4 and cutting off the adjustable load 3B having a high achievement rate 45B4.

  Here, the power load adjusting device 4 acquires measurement data of the bank power amount (total power amount) (S509). The bank power amount is a total value of the power amount used in the lower system, which is collectively measured by the transformer 1. Then, it is determined whether or not the measured value is larger than the average value × α (second predetermined value) (S510). α is a coefficient larger than 1 and indicates the likelihood of the predicted electric energy, and the average value × α is a lower limit value for determining that the measured value is excessive. If the measured value is larger than the average value × α (Yes in S510), it means that the actual power amount is out of the predicted value and is large (excessive), so it is necessary to suppress the power amount. Therefore, the power load adjustment device 4 extracts a lower load (high achievement rate) 3B from the input list 45C of the storage unit 45 (S511). Next, the watt hour meter 2 at the customer's house is instructed to shut off the load 3B (S512). Then, re-blocking of the load 3B at the time is prohibited (S513). As a specific method of prohibiting re-blocking, there is a method of deleting the customer ID 45C1 of the blocked load 3B from the data in the time zone of the input list 45C. Thereby, the load 3B once interrupted at the time is not interrupted again in the process at the same set time. Thereafter, the process returns to S509.

  When the measured value is not larger than the average value × α (No in S510), the power load adjusting device 4 determines whether or not the measured value is larger than the average value (first predetermined value) (S514). If the measured value is not larger than the average value (No in S514), it means that the actual power amount is lower than the predicted value, so the power amount needs to be increased. Therefore, the upper load 3B (low achievement rate) is extracted from the input list 45C of the storage unit 45 (S515). Next, the watt hour meter 2 of the customer's house is instructed to input the load 3B (S516). Then, recharging of the load 3B at the time is prohibited (S517). As a specific method of prohibiting re-input, there is a method of deleting the customer ID 45C1 of the input load 3B from the data in the time zone of the input list 45C. Thereby, the load 3B once input at the time is not input again in the process at the same set time. Thereafter, the process returns to S509.

  When the processes of S515 to S517 are performed twice or more in the process at the same set time, the second and subsequent loads 3B from the top of the input list are sequentially instructed.

  When the measured value is larger than the average value (Yes in S514), the actual power amount is between the average value of the predicted power amount and the average value × α (α> 1) together with the determination result in S510. Since it is close to the value, it is considered that the electric energy of the adjustable load 3B is leveled. Accordingly, in this case, the power load adjustment device 4 waits for the next set time after the instruction to turn on or off the load 3B at that time is finished.

  When the elapsed time t = 0 in S505 (Yes in S505), the measured value of the bank power acquired in S509 is close to zero, so it is considered that the determinations in S510 and S514 are both No. Therefore, the power load adjusting device 4 extracts the higher-order load 3B (S515), and gives an instruction to input the load 3B (S516). At this time, the input list 45C is in the descending order of the predicted power amount initially set in S503, and from the load 3B predicted to use a large amount of power at the first set time when entering the midnight time zone. Will be thrown in.

  Although the embodiment of the present invention has been described above, in order to make each unit in the power load adjusting device 4 shown in FIG. 3 function, a program executed by the processing unit 44 is recorded on a computer-readable recording medium, It is assumed that the power load adjustment system S according to the embodiment of the present invention is realized by causing the computer to read and execute the recorded program. Note that the program may be provided to the computer via a network such as the Internet, or a semiconductor chip or the like in which the program is written may be incorporated in the computer.

  According to the embodiment of the present invention described above, the opening / closing operation unit 20 (see FIG. 2A) corresponding to the adjustable load 3B connected between the load side terminals 121-124 of FIG. Since the terminals 213-223) are provided, the load can be turned on and off for each adjustable load 3B. And since each load 3B is interrupted | blocked and turned on according to the order based on prediction electric energy or achievement rate according to the magnitude of the total electric energy of load 3B which can be adjusted of the subordinate system of transformer 1, electric power of each load 3B The amount can be leveled. According to this, the bottleneck that the transformer 1 is overloaded can be eliminated. For example, when charging an electric vehicle, there is room for the power to be supplied, so the transformer 1 can be used efficiently.

  According to the above, the electric energy of each adjustable load 3B of the subordinate system of the transformer 1 can be leveled, so that effective use of distribution equipment, reduction of transmission loss of low-voltage distribution lines, and prevention of double weighing Can do.

<< Other embodiments >>
As mentioned above, although the form for implementing this invention was demonstrated, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention. For example, the following embodiments can be considered.

(1) In the above embodiment, the opening / closing operation unit 20 in the watt hour meter 2 performs turning on and off of the adjustable load 3 </ b> B, but it is limited to turning on and off in the watt hour meter 2. Never happen. For example, a circuit breaker may be provided between the watt-hour meter 2 and the adjustable load 3B, and the circuit breaker may be turned on and off. In this case, the power load adjusting device 4 communicates with each circuit breaker and gives instructions for turning on and off.

(2) In the above embodiment, the adjustable load 3B is connected between the load-side terminals 121-124 of the watt-hour meter 2, but one watt-hour meter 2 is one adjustable load 3B. The watt-hour meter 2 may connect two or more adjustable loads 3B and measure the electric energy of these loads 3B. In that case, a new load-side terminal and a current sensor are provided in the watt-hour meter 2, and a customer ID corresponding to the new load 3B (as identification information unique to the load) is stored in each data in the storage unit 45 of the power load adjusting device 4. Will be added). And you may make it allocate an electric vehicle and an electric water heater as 2 or more adjustable load 3B.

(3) The electric power company may measure the amount of power in the load adjustment portion between the load-side terminals 121-124 of the watt-hour meter 2, and may discount the electricity rate related to the amount of power. Since the consumer cooperates with load adjustment in the midnight time zone, it is considered that such a privilege may be provided. For example, since it is desired to charge a lot when going out with an electric vehicle, a method of using the load-side terminals 121-124 with lower electric charges instead of the normal load-side terminals 121-123 can be considered.

1 Transformer 2 Electricity meter 20 Switching operation part (breaker)
30 Metering unit 3 Load 4 Power load adjusting device 44 Processing unit 45 Storage unit 45A2 Predicted power amount 45B2 Measured power amount 45B3 Achievement rate L1 Distribution system L2 Electric wire S Load adjustment system

Claims (1)

A system-side terminal connected to the power distribution system and receiving power supplied from the power distribution system;
A first load that is connected to a first load that is allowed to interrupt power supply, and that supplies power received from the distribution system to the first load;
A second load that is connected to a second load that is not allowed to interrupt power supply, and that supplies power received from the distribution system to the second load;
A metering electronic circuit for measuring the amount of power used by the first and second loads;
A cut-off signal receiving unit for receiving a cut-off signal indicating that the load should be cut off via the communication line;
A circuit breaker that cuts off the power supply to the first load side terminal when the interruption signal receiving unit receives the interruption signal;
A watt-hour meter comprising:

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