JP2010074991A - Independent power demand controller and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an independent power demand controller and its method which reduces the fluctuations in the power demand of a specific load device from among a plurality of load devices which are supplied with power from a power system. <P>SOLUTION: The independent power demand controller 11 includes an impedance measuring unit 12 and an operation and power consumption control unit 13. The impedance measuring unit 12 measures the impedance of a power system 1, as viewed from a load device 3-1. The power consumption control unit 13 searches for a table which shows the relationship between an impedance value and an amount of power demand of a load section 10 of the load device 3-1 and estimates the power demand of the load section 10, based on the measured impedance value, and determines whether the load section can be operated, based on the estimated power demand. When the load section 10 can be operated, it is decided that the target value for power consumption and instructs the load section 10 to operate with the targeted power consumption. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for controlling power consumption of a load device installed in a consumer who receives power supplied from an electric power system.

  In small household fuel cells and gas engine generators, control is generally performed so as not to cause so-called reverse power flow in which generated electric power is supplied to the power system. For this purpose, it is necessary to always control the output so that the power generation output does not exceed the power demand. However, when a load device is used in a random manner in ordinary households, the power demand changes rapidly over time, and it is necessary to change the power generation output frequently and over a wide output range. Cause a decrease in operating rate or operating rate.

  Apart from the above problems, the spread of high-load equipment such as IH (Induction Heating) cooking heaters and bathroom heaters and dryers has rapidly increased the maximum power in general households. The basic fee is forced to rise. In particular, in apartment buildings, the peak time periods of demand for electricity in each unit overlap, which necessitates excessive equipment for the average daily load, which has been a factor in reducing the equipment usage rate.

  The above problems will become more serious if electric vehicles and plug-in hybrid vehicles become widespread in the future. This is because it is necessary to cover the amount of power consumed in the order of several hours on the order of several hours of household power consumption per day, and the charge demand periods of each household tend to overlap. Expected to be. Further, at the end of charging, charging and stopping are repeated intermittently along with the control of the battery voltage, and this can be a serious problem that cannot be compared with the conventional one in terms of demand fluctuation. In order to cope with such a problem, some control for dispersion of demand generation time zones and suppression of the maximum demand is necessary.

  As a method for alleviating these problems, for example, the power demand at the power receiving point may be measured, and the load may be controlled so as to reduce the fluctuation of the power demand as much as possible or suppress the maximum power based on the measurement result. . It is conceivable to apply HEMS (Home Energy Management System) as a means for this control (Non-patent Document 1).

However, since the power demand measuring unit is provided at a point away from the load, standardized communication means and control specifications for exchanging measurement results or control information with the load are required. However, particularly in the case of household devices, the introduction time and device life are not constant, and the suppliers are diverse, so it is very difficult to standardize communication and control specifications.
NEDO (New Energy and Industrial Technology Development Organization), 2006 Survey Report “Survey on DC power supply for home use for fuel cells”, pp. 79-80

  An object of the present invention is to provide a self-contained power demand control device and method that alleviates fluctuations in power demand of a load (hereinafter referred to as a load device).

  In order to achieve this object, according to the present invention, a stand-alone power demand control device is provided in a specific load device, for example, a power device having a large power demand, in a consumer to which power is supplied from the power system. This self-contained power demand control device is based on impedance measurement means for measuring impedance on the power system side (line impedance of power supply line from the power system) viewed from the load device, and based on the measured impedance value. Then, a table showing the relationship between the impedance and the power demand amount of the load device is searched, the power demand of the load device is estimated, and at least the availability of the load device is determined based on the estimated power demand, If possible, it has an operation / power consumption control means for determining a target value of power consumption of the load device and commanding the target value to the load device.

  The line impedance of the power supply line is a combined impedance of the impedance of the power system and the impedance of the load device in the consumer. Among these, since the impedance of the load device is determined by the operation state of the load device, the power demand of the load device can be estimated from the combined impedance.

  When the impedance is low, that is, when it is estimated that the power demand is large, the target value of power consumption is set to be small so that the operation of the load device is refrained. On the contrary, when it is estimated that the impedance is high, that is, the power demand is small, the high load operation is performed in the necessary range or the load device is actively operated. Thereby, the electric power demand of a load apparatus can be optimized and the fluctuation | variation of an electric power demand can be suppressed.

  Basically, impedance and power demand are inversely related. However, this relationship is not simply determined due to the influence of wiring in the middle and the control method in the load device. Therefore, the relationship between the impedance and the power demand is created by matching with the demand measurement result obtained separately or the result obtained in advance by another experimental system, and correction at any time in the field by learning.

  Here, since the impedance of the power system is extremely lower than the impedance of the load device that is the target of power demand estimation, it is difficult to capture the operating state of the load device. However, by appropriately selecting the frequency at which the impedance is measured so as to capture the parasitic impedance of the power supply equipment such as the lead-in wire and the columnar transformer, the operating state of the load device can be captured separately from the power system. it can.

  Further, by inserting an impedance part for increasing the impedance to the signal for measuring the impedance between the power system and the load device group, the impedance of the power system viewed from the load is increased, and the load device group It is possible to easily detect the change in the combined impedance.

  When measuring the impedance, the impedance between the power supply lines is not simply measured, but only the impedance above the load device is measured. As a result, the influence of the operating state of the load device can be eliminated, so that more accurate control is possible.

  According to the present invention, the impedance on the power system side viewed from a specific load device of a consumer supplied with power from the power system is measured, and the power demand of the load device is determined based on the measured impedance value. And at least whether the load device can be operated based on the estimated value of the power demand, and if possible, at least a target value of power consumption of the load device based on the estimated power demand By determining and commanding the target value to the load device, there is an effect that the power demand of the load device can be optimized and fluctuation of the power demand can be suppressed. As a result, the maximum power can be suppressed, investment in facilities for receiving and distributing power can be suppressed, and the daily load rate is improved, leading to an improvement in facility usage rate. At the same time, it contributes to the reduction of the basic electricity bill. Moreover, when it has power generation equipment on the load device side, power generation efficiency and equipment operation rate can be improved.

  Next, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
FIG. 1 shows a connection between a power system and a plurality of load devices in a consumer in the first embodiment of the present invention. The electric power of the power system 1 is distributed to the n load devices 3-1 to 3-n and the n load devices 4-1 to 4-n via the power supply line 2. Here, the load devices 3-1 to 3-n are load devices that incorporate the self-supporting power demand control device 11 of the present invention in addition to the load unit 10, and the load devices 4-1 to 4-n are self-supporting. The load device does not include the power demand control device 11. The load device incorporating the self-supporting power demand control device 11 is, for example, a load device with a large power demand. The self-supporting power demand control device 11 determines whether or not the load unit 10 can be operated based on the impedance measurement unit 12 that measures the impedance on the power system side viewed from the load device and the impedance measured by the impedance measurement unit 12. If it is possible, an operation / power consumption control unit 13 for determining a target value of the power consumption and instructing the target value to the load unit 10 is included.

  FIG. 2 shows the configuration of the impedance measuring unit 12. The impedance measurement unit 12 includes a signal generation unit 12a, a signal application unit 12b, a signal voltage measurement unit 12c, a signal current measurement unit 12d, and an impedance determination unit 12e. The signal generator 12a generates an impedance measurement signal that is a signal for measuring impedance. The frequency of the impedance measurement signal is set higher than the frequency of the power supplied from the power system 1. When setting the frequency, it is necessary to select a frequency range that makes the impedance of the power system 1 high and reflects the operation state of the load device incorporating the inverter and the switching power supply. Further, in order to facilitate measurement, it is necessary to avoid the influence of the frequency of the supplied power and its harmonic components, and a frequency region close to the power supply frequency is not preferable in terms of ease of measurement. Conversely, if a too high frequency is selected, if there is a noise filter at the entrance of the load device, the power supply lines are short-circuited at high frequencies, and information about the load device is cut off. Absent. In practice, for example, a signal frequency suitable for the measurement condition is selected within a frequency range of several kilohertz to several megahertz. The signal applying unit 12 b applies the impedance measurement signal to the power signal from the power supply line 2. The signal voltage measuring unit 12c measures the applied voltage of the signal. The signal current measuring unit 12 d measures the current value of the signal current that flows toward the power supply line 2. The impedance determination unit 12e obtains the impedance, that is, the ratio between the applied voltage measured by the signal voltage measurement unit 12c and the current value measured by the signal current measurement unit 12d. The impedance may be obtained by using a plurality of frequencies as the frequency of the signal for measurement, or by combining the results obtained while continuously changing the frequency.

  In the impedance measuring unit 12, the signal current measuring unit 12d is provided closer to the power supply line 2 than the signal applying unit 12b. Thereby, since the synthetic | combination impedance except the said load part 10 can be caught, electric power demand control does not depend on the driving | running state of the own load part 1, and control and determination become easier.

  FIG. 3 is a diagram showing a configuration of the operation / power consumption control unit 13. The operation / power consumption control unit 13 includes a storage unit 13a, a power demand estimation unit 13b, and an operation determination / power consumption target value setting unit 13c. The storage unit 13a stores a table as shown in Table 1 indicating the relationship between impedance and demand.

The power demand estimation unit 13b searches the table (Table 1) stored in the storage unit 13a based on the measurement result (impedance value) obtained from the impedance measurement unit 12, and the power demand corresponding to the impedance value. Estimate the size of. For example, the impedance value of the measurement result is Ix, this Ix is in the range of Ia and Ib (where Ia <Ib), and the range of power demand corresponding to this impedance range Ia-Ib is Pa-Pb (where Pa In the case of> Pb), the estimated value Py of the power demand is obtained by Pb + (Pa−Pb) × (Ib−Ix) / (Ib−Ia) by proportional calculation. The estimated value of power demand is not necessarily an absolute value. For example, it may be a maximum allowable power or a relative value with respect to the maximum target power. The operation determination / power consumption target value setting unit 13c determines whether or not the load unit 10 can be operated based on the obtained estimated power demand, and if the operation is possible, sets the target value of power consumption of the load unit 10. The target value is determined and commanded to the load unit 10. It should be noted that the operation information of the load unit 10 is referred to as necessary, and is used as a determination material when determining the availability of operation and target power consumption. This is because, depending on the process that the load unit 10 is executing, it may be difficult to interrupt the operation or change the consumption. The operation information of the load unit 10 indicates which process in the process group pre-installed in the load unit 10 in the recipe is currently being executed, or what control state (control margin) the device that is the load unit 10 has. The information indicates whether the request of the operation / power consumption control unit 13 is available or not. Data indicating the relationship between impedance and power demand may be stored in advance in the storage unit 13a, or may be stored in the storage unit 13a each time during actual operation.

  FIG. 4 is a flowchart showing the operation of the self-supporting power demand control apparatus 11. The impedance measuring unit 12 receives an activation request from the user (step 101), and measures the impedance in order to estimate the power demand situation (step 102). Based on the measurement result, the power demand estimation unit 13b of the operation / power consumption operation control unit 13 searches the table indicating the relationship between the impedance and the power demand stored in the storage unit 13a, and the magnitude of the power demand. Is estimated (step 103). The operation determination / power consumption target value setting unit 13c determines whether or not the operation is possible based on the obtained estimated value of power demand, that is, whether or not there is a margin in power (step 104). However, at this time, the operation information of the load unit 10 is taken in, for example, as a material for determining whether or not the operation can be interrupted. If it is determined in step 104 that there is no margin for operating power and “operation is not possible”, the load unit 10 is instructed to wait, and the processing in steps 102 and 103 is repeated at regular intervals. If it is determined in step 104 that “operation is possible”, a target value of power consumption is determined (step 105). At this time, similarly to the previous step 104, the operation information of the load unit 10 is taken and used as a material for determining the target value of power consumption. The obtained target value is commanded to the load unit 10 (step 106). At the same time, the processing from step 102 to step 105 is repeated at regular intervals to monitor the change in power demand. If there is a change, whether or not the operation is possible is determined according to the above (step 104), and the new power consumption is determined. A target value is determined (step 105).

[Second Embodiment]
FIG. 5 shows a connection between a power system and a plurality of load devices in a consumer in the second embodiment of the present invention. In the present embodiment, in the first embodiment, the impedance unit 5 is provided between the power system 1 and the load devices 3-1 to 3-n and 4-1 to 4-n in the power supply line 2. Is.

  The impedance unit 5 shows a high impedance when the power system 1 is viewed from the load devices 3-1 to 3-n, and captures a change in the combined impedance caused by a change in the operation state of the load devices 3-1 to 3-n. This is to make it easier. The impedance unit 5 only needs to exhibit a predetermined impedance with respect to the signal frequency for measuring the impedance, and the component may be an inductor or a resonance circuit.

[Third Embodiment]
FIG. 6 shows a connection between a power system and a plurality of load devices in a consumer in the third embodiment of the present invention. In the present embodiment, the independent power demand control devices 11-1 to 11-n are installed outside the load devices 6-1 to 6-n. The configuration and operation of the stand-alone power demand control devices 11-1 to 11-n are the same as the stand-alone power demand control device 11 in the first embodiment.

[Fourth Embodiment]
FIG. 7 shows a connection between a power system and a plurality of load devices in a consumer in the fourth embodiment of the present invention. In the third embodiment, in the third embodiment, the power supply line 2 is connected between the power system 1 and the independent power demand control devices 11-1 to 11-n and the load devices 4-1 to 4-n. An impedance unit 5 is provided.

[Fifth Embodiment]
The function of the power demand control apparatus is to record a program for realizing the function on a computer-readable recording medium, and cause the computer to read and execute the program recorded on the recording medium. There may be. The computer-readable recording medium refers to a recording medium such as a flexible disk, a magneto-optical disk, a CD-ROM, or a storage device such as a hard disk device built in a computer system. Furthermore, the computer-readable recording medium is a medium that dynamically holds the program for a short time (transmission medium or transmission wave) as in the case of transmitting the program via the Internet, and the computer serving as the server in that case Such as a volatile memory that holds a program for a certain period of time.

FIG. 1 is a diagram showing a connection between a power system and a load device in the first embodiment of the present invention. FIG. 2 is a block diagram of the impedance measurement unit of the self-contained power demand control apparatus. FIG. 3 is a block diagram of the operation / power consumption control unit of the self-contained power demand control apparatus. FIG. 4 is a flowchart showing the operation of the self-supporting power demand control apparatus. FIG. 5 is a diagram showing the connection between the power system and the load device in the second embodiment of the present invention. FIG. 6 is a diagram showing the connection between the power system and the load device in the third embodiment of the present invention. FIG. 7 is a diagram showing the connection between the power system and the load device in the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric power system 2 Electric power supply line 3-1 to 3-n Load apparatus 4-1 to 4-n Load apparatus 5 Impedance part 6-1 to 6-n Load apparatus 10 Load part 11 Self-supporting electric power demand control apparatus 11 -1 to 11-n Independent power demand control device 12 Impedance measurement unit 12a Signal generation unit 12b Signal application unit 12c Signal voltage measurement unit 12d Signal current measurement unit 12e Impedance measurement unit 13 Operation / power consumption control unit 13a Storage unit 13b Power Demand Estimation Unit 13c Operation Determination / Power Consumption Target Value Setting Unit 101-106 Steps

Claims (10)

It is installed for a specific load device in a consumer who is supplied with power from the power grid,
Impedance measuring means for measuring the impedance of the power system as seen from the load device;
Based on the measured impedance value, a table indicating the relationship between the impedance and the power demand amount of the load device is searched to estimate the power demand of the load device, and at least based on the estimated value of the power demand It is determined whether or not the load device can be operated. If possible, a target value of power consumption of the load device is determined based on at least the estimated value of the power demand, and the target value is commanded to the load device. Operation / power consumption control means,
A self-contained power demand control apparatus. The impedance measuring means includes
A signal generator for generating an impedance measurement signal which is a signal for measuring impedance;
A signal applying unit for applying the impedance measurement signal to a power signal from a power supply line of the power system;
A signal voltage measurement unit for measuring an applied voltage of the impedance measurement signal;
A signal current measurement unit that measures a current value of a signal current of the impedance measurement signal that flows toward the power supply line; and
An impedance determination unit for obtaining an impedance from a ratio of an applied voltage measured by the signal voltage measurement unit and a current value measured by the signal current measurement unit;
The self-supporting power demand control apparatus according to claim 1, comprising:   The self-supporting power demand control apparatus according to claim 2, wherein the signal current measuring unit is provided closer to the power supply line than the signal applying unit. The operation / power consumption control means is:
A storage unit storing a table showing the relationship between the impedance and the power demand of the load device;
Based on the impedance value that is the measurement result obtained by the impedance measurement means, a power demand measurement unit that searches the table stored in the storage unit and estimates the magnitude of the power demand of the load device;
It is determined whether or not the load device can be operated based on the estimated value of the power demand. If possible, at least a target value of power consumption of the load device is determined based on the estimated power demand, and the target An operation determination / power consumption target value setting unit for instructing a value to the load device;
The self-supporting electric power demand control apparatus according to any one of claims 1 to 3, further comprising:   The self-supporting power demand control apparatus according to any one of claims 1 to 4, wherein an impedance unit is provided between the power system and the load device of the power supply line.   The self-supporting power demand control apparatus according to any one of claims 1 to 5, wherein the impedance measurement unit measures impedance using a signal having a frequency higher than a frequency of supplied power.   The self-supporting power demand control apparatus according to any one of claims 1 to 6, wherein the impedance measuring unit measures an impedance on a power system side of the load device. Measuring the impedance on the power system side as viewed from a specific load device in a consumer supplied with power from the power system;
Based on the measurement result, searching a table showing the relationship between the impedance and the power demand of the load device, and estimating the magnitude of the power demand;
At least a step of determining whether or not the load device is operable based on the obtained estimated power demand value, and if determined to be operable, at least based on the estimated power demand value Determining a target value of power consumption of the load device,
Commanding the determined target value of power consumption to the load device;
An electric power demand control method.   If it is determined that the operation is impossible, the process returns to the step of measuring the impedance, the standby is instructed to the load device, and the process is repeated from the first step every predetermined period. The power demand control method described in 1. A procedure for measuring the impedance on the power system side as viewed from a specific load device in a consumer to which power is supplied from the power system;
Based on the measurement results, a table that shows the relationship between the impedance and the power demand of the load device is retrieved, and a procedure for estimating the magnitude of the power demand;
At least a step of determining whether or not the load device is operable based on the estimated value of power demand obtained;
When it is determined that the operation is possible, at least a procedure for determining a target value of power consumption of the load device based on the estimated value of the power demand;
A procedure for instructing the determined target value of power consumption to the load device;
Power demand control program for causing a computer to execute.

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