JPH11206015A - Method and apparatus for monitoring demand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easier for customers to judge to what extent loads in operation should be adjusted, if an predicted demand exceeds a target demand, and allow the customers to appropriately monitor the demand. SOLUTION: If an predicted electrical energy required R calculated from an electrical energy presently consumed by loads P and the rate of increase in electrical energy consumed (power consumed) expressed as the electrical energy consumed with respect to a certain the frame Δt,(ΔP/Δt) exceeds a target electrical energy required Q which is set for a specified time limit T, an alarm is issued and an instruction is provided to cut the present power consumed. In order to control the electrical energy presently consumed P to be within a predicted electrical energy required R, a rate of reduction B indicating to what extent the present power consumed should be reduced is calculated, based on the value for the estimated electrical energy required R, and is displayed in percent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demand power monitoring method and apparatus for monitoring and controlling a demand power amount contracted by a power customer with a power supply company.

[0002]

2. Description of the Related Art A demand power monitoring device monitors and controls a power consumption within a demand time period (a predetermined time, generally 15 minutes or 30 minutes) so as not to exceed a contract power amount (target demand power). FIG. 6 is a time chart showing the operation of the conventional demand power monitoring device disclosed in Japanese Patent Publication No. 60-9412, for example. In FIG. 6, the horizontal axis indicates time, and the demand time period is T, and the elapsed time within the demand time period is t.
The vertical axis indicates the power demand, and Q is a preset target power demand, for example, a contract power demand. P is the power consumption from the start of the time period to the elapsed time t, that is, the current power demand.

[0003] At the time point of the elapsed time t, a fixed time width Δt is set at a shorter interval, and an increment of the power consumption of the fixed time width Δt is set as ΔP. Where ΔP /
By the calculation of ΔT, the rate of increase of the power consumption, that is, the current power consumption, is obtained, and the value of the current power consumption P is extended assuming that the remaining time (Tt) until the demand time limit T continues in this state. And the predicted value of the required power amount in the demand time period T, that is, the predicted required power amount R is obtained.
The predicted power demand R is represented by the following equation (1). R = P + (T−t) · ΔP / Δt (1) Then, when a calculation result in which the predicted demand power R exceeds the target demand power Q appears, a supervisor issues a warning and performs load control. It is to call attention.

As information for performing load control, a difference between a predicted demand power amount R and a target demand power amount Q is represented by a remaining time (T−
From the value divided by t), the adjusted power to reduce the power consumption at the present time is obtained. Assuming that the adjusted power is U, it is expressed by the following equation (2). U = (R−Q) / (T−t) (2) That is, if the adjusted power U is cut from the current use power (instantaneous power) over the remaining time (T−t),
The power consumption in the demand time period falls within the target power demand Q. The observer stops the operation of the load equipment or reduces the output corresponding to the adjusted power U.

[0005]

In the demand power monitoring for performing the load control as described above, for example, in the case of a customer who does not have a specialist in electrical equipment, there is a case where the load capacity of each equipment cannot be sufficiently grasped. In many cases, it is not possible to grasp how much the load capacity (adjusted power) to be controlled in the entire load, so that it may not be possible to narrow down the target of the load to be controlled.

The present invention has been made to solve such a problem, and a demand power monitoring method and apparatus for constantly informing a supervisor of a load capacity to be controlled as a ratio to operating equipment. It is intended to provide.

[0007]

A demand power monitoring method according to the present invention is based on a current power consumption of a load and a power consumption increase rate (power consumption) represented by a power consumption for a fixed time width. A demand power monitoring method in which a warning is issued when the calculated expected demand power exceeds a target demand power set in advance for a predetermined time period and a current power consumption is cut off. In order to store the power amount, a suppression rate indicating how much the current power consumption should be suppressed is obtained by calculation based on the value of the predicted demand power amount, and is displayed as a percentage.

In the above method, the suppression rate is a ratio of the power to be cut to the current power consumption.

[0009] The suppression rate is a ratio of the available power after the present to the current used power.

[0010] Further, when the predicted power demand exceeds the target power demand, the predetermined time width for obtaining the rate of increase in the power consumption is reduced.

Further, the demand power monitoring apparatus according to the present invention comprises a pulse transmitting means for transmitting a pulse proportional to the power consumption of the load, and a current power consumption for counting the pulses from the pulse transmitting means in a predetermined time period. Counting means, first calculating means for counting pulses from the pulse transmission means at a fixed time width, and calculating a current power consumption increasing rate (power consumption) from the number of pulses counted at the fixed time width; A second calculating means for calculating a predicted power demand based on an output of the used power counting means, the current rate of increase of the used power, and the remaining time until the predetermined time period; A comparing means for outputting an output when the output exceeds a preset target demand power amount; an alarm means for issuing an alarm by the output of the comparison means; and a means for keeping the predicted demand power amount within the target demand power amount. A third calculating means for calculating the adjusted power to be adjusted for the current used power, and a fourth calculating means for calculating the current power used suppression rate as a percentage from the third calculating means and the output of the first calculating means. It is provided with a calculating means and a display means for displaying a percentage which is an output of the fourth calculating means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing a demand power monitoring apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a time chart showing the operation thereof. In the figure, reference numeral 1 denotes a device for transmitting the number of pulses in proportion to the power consumption, for example, a power meter with a transmitter. Reference numeral 2 denotes a current power consumption counter that counts the transmission pulses of the watt hour meter 1 with the transmission device, and is reset at every demand time T by a signal of a clock unit 4 described later. Reference numeral 3 denotes a power consumption increment counter, which repeats resetting at predetermined time intervals Δt in response to a signal from the clock unit 4 to count pulses during each fixed time width Δt to obtain a power consumption increment ΔP. Reference numeral 4 denotes a clock section, which measures a demand time period T and a fixed time width Δt, and outputs a reset signal for the two counters 2 and 3 at each time interval. Reference numeral 5 denotes a remaining time counter which counts a difference between the demand time period T and the current time t, that is, a remaining time (T-t) of the demand time period, based on a reference signal from the clock unit 4.

Reference numeral 6 denotes a first arithmetic circuit, which is a circuit for calculating an increase rate Y (Y = ΔP / Δt) of the current power consumption, that is, the current power consumption, and a power consumption increment counter for every fixed time width Δt. Calculate from the value of 3. 7 is a second arithmetic circuit,
The predicted power demand R in the above equation (1) is calculated from the output signals of the current power consumption counter 2, the power consumption increment counter 3, and the remaining time counter 5, and the fixed time width Δt. 8
Is a target power demand setting device for setting a target power demand, for example, a contract power demand. Reference numeral 9 denotes a third arithmetic circuit, which calculates the adjusted power U from the output signal of the second arithmetic circuit 7, the target demand power setting device 8, and the remaining time counter 5 by the above equation (2). Reference numeral 10 denotes a fourth arithmetic circuit. The output power of the first arithmetic circuit 6 and the third arithmetic circuit 9 is used as a percentage to cut the current power consumption in order to keep the power consumption within the target demand power Q. Suppression rate B (B = U / Y)
× 100%). This suppression rate B is a negative value if “target demand power Q> predicted demand power R”.

Reference numeral 11 denotes a comparison circuit, and the second operation circuit 7
Is compared with the target demand power Q which is the output from the target demand power setting unit 8, and when the former exceeds the latter, an alarm output is generated and the alarm circuit 12 is operated. . Reference numeral 13 denotes a display, which displays a predicted power demand R, a suppression rate B, a target power demand Q, and the like. The display on the display 13 and the operation of the alarm device 12 inform the user of the necessity of load adjustment, and call attention to the monitor.

Next, the display 13 will be described with reference to FIG. 3, reference numeral 14 denotes a remaining time display unit, 15 denotes a predicted power demand display unit that digitally displays the predicted power demand R, 16 denotes a power consumption display unit that digitally displays the power demand P at the current time t, 17 Is a target power demand display section for digitally displaying the target power demand Q. Reference numeral 18 denotes a suppression rate display unit for displaying the suppression rate B as a digital value as a percentage, reference numeral 19 denotes a used power amount analog display unit for displaying the current used power amount P in an analog manner, and reference numeral 22 denotes a scale for the used power amount analog display unit 19. Numeral, 20 is a suppression rate analog display section for displaying the suppression rate B in an analog manner, 21 is a scale numeral for the suppression rate analog display section 20, and 23 is an instruction for instructing the suppression rate on the analog display section 20 for displaying the suppression rate B. Mark. These display units are constituted by LEDs or LCDs. When the condition of the alarm output is satisfied in the comparison circuit 11 that compares the predicted demand power R and the target demand power Q, the position of the value corresponding to the suppression rate B is set. Is indicated by the instruction mark 23, and the entire screen flashes to indicate an alarm state.

Then, when the monitor disconnects the load that can be stopped at the present time, the predicted demand power R and the suppression rate are calculated with the used power after the load disconnection in the next fixed time width Δt + 1 and displayed on the display unit 13. . At this point, the suppression rate B is 0
%, The used electric energy P falls within the target demand electric energy Q without interruption for the remaining time (T-t). However, when a positive numerical value is displayed as the suppression rate B,
Another stoppable load corresponding to the suppression rate is additionally cut off to see how the suppression rate B becomes 0% or less.
When a negative value is displayed for the suppression rate B, it is possible to re-enter a part of the cut load within a range where the suppression rate B does not exceed 0%.

In the above description, the load cut target is displayed as a percentage as a suppression rate. However, it is also possible to calculate and display what percentage the current power consumption should be. The suppression rate C in this case is: C = 100 * {(Q−P) / (T−t)} (ΔP / Δ
t) is calculated. That is, the ratio of the available electric power after the present to the present electric power is used. When the display of the suppression rate C is, for example, 90%, 10% is required to keep the electric power consumption P within the target demand electric power Q. Means that the load cut is necessary, and when the display of the suppression rate C is 120%, 20
% Means that there is room.

Embodiment 2 FIG. FIG. 4 is a block diagram showing a demand power monitoring apparatus according to Embodiment 2 of the present invention, and FIG. 5 is a partial view of a time chart of Embodiment 2. In the figure, 1 to 13 are the same as those in the first embodiment. 4a is a time width switching means, which receives the output from the comparison circuit 11 and shortens the fixed time width Δt. The normal fixed time width Δt is set to 1 to 3 minutes, but after switching, it is set to 15 seconds to 1 minute. If the time is shorter than this, the calculation result varies due to the influence of the power fluctuation of the load, so that about 30 seconds is desirable.

The operation of the second embodiment will be described with reference to FIG. When predicted power demand R at point P in FIG. 5 exceeds target power demand Q, an alarm from alarm circuit 12 gives
The load cut operation is performed at the point P1 within the next fixed time width Δt + 1. The power consumption up to the time of the load cut is reflected in the predicted demand power amount in the next fixed time width Δt + 1,
The predicted demand power amount is a predicted demand power amount R1 different from the predicted demand power amount R2 based on the used power after the load is cut.
Therefore, in order to obtain the accurate predicted power demand R2, it is necessary to further wait for the calculation of the fixed time width Δt + 2. When the remaining time (T-t) until the demand time period T is short, the load adjustment result is quickly known and appropriate load adjustment is required. Therefore, when the normal fixed time width Δt is 1 to 3 minutes, the load adjustment timing is set. Lose. Therefore, in the second embodiment, the output from the comparison circuit 11 is detected as soon as possible, whereby the time width switching means 4a detects the fixed time width Δ
t is reduced, and the power demand prediction operation cycle is accelerated. As a result, a more accurate predicted power demand is obtained, and the timing of load adjustment is not lost.

[0020]

As described above, according to the present invention, when the predicted power demand exceeds the target power demand, an alarm is issued and the suppression rate is displayed as a percentage on the display. In addition, even an unskilled person can quickly and appropriately judge the degree of load reduction, and effective power demand monitoring can be performed.

Further, when the predicted power demand exceeds the target power demand, the time width for measuring the rate of increase of the power consumption is reduced, so that the power demand prediction operation cycle can be accelerated and more accurate. By obtaining the predicted power demand, the load adjustment can be performed more appropriately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a power demand monitoring device according to Embodiment 1 of the present invention.

FIG. 2 is a time chart illustrating the operation of the first embodiment.

FIG. 3 is a diagram illustrating a display unit of the display device according to the first embodiment.

FIG. 4 is a block diagram showing a power demand monitoring device according to Embodiment 2 of the present invention.

FIG. 5 is a partial view of a time chart explaining the operation of the second embodiment.

FIG. 6 is a time chart illustrating the operation of a conventional demand power monitoring device.

[Explanation of symbols]

1 watt-hour meter with transmitting device, 2 current power consumption counter, 3 power consumption increment counter, 4 clock section, 4a
Time width switching means, 5 remaining time counter, 6 first operation circuit, 7 second operation circuit, 8 target power demand setting device, 9 third operation circuit, 10 fourth operation circuit, 11
Comparison circuit, 12 alarm circuit, 13 display, 14 remaining time display, 15 predicted demand power display, 16 used power display, 17 target demand power display, 18
Suppression rate display, 19 Power consumption analog display, 20
Analog display of suppression rate.

Claims (5)

[Claims] 1. An expected power demand obtained from a current power consumption of a load and a power consumption increase rate (power consumption) expressed by a power consumption for a certain time width is set in advance for a predetermined time period. A demand power monitoring method that issues a warning when the target demand power is exceeded and instructs the current power consumption cut, and includes a value of the predicted demand power in order to store the power consumption within the target demand power. A demand power monitoring method characterized in that a suppression rate indicating how much the current power consumption should be suppressed is calculated by calculation based on the calculated power consumption, and is displayed as a percentage. 2. The demand power monitoring method according to claim 1, wherein the suppression rate is a ratio of power to be cut to current power consumption. 3. The demand power monitoring method according to claim 1, wherein the suppression rate is a ratio of the available power after the present to the current used power. 4. The system according to claim 1, wherein when the predicted power demand exceeds the target power demand, the predetermined time width for obtaining the power consumption increase rate is reduced. Demand power monitoring method described. 5. A pulse transmitting means for transmitting a pulse proportional to the power consumption of a load, a current power consumption counting means for counting pulses from the pulse transmitting means in a predetermined time period, and A first calculating means for counting pulses in a fixed time width and calculating a current power consumption increase rate (power consumption) from the number of pulses counted in the fixed time width; an output of the current power consumption counting means; A second calculating means for obtaining a predicted power demand based on the current power consumption increasing rate and the remaining time up to the predetermined time period, and an output of the second calculating means being a preset target demand power Comparing means for outputting an output when the power consumption exceeds, an alarming means for issuing an alarm based on the output of the comparing means, and an electric power to be adjusted for the current used electric power so as to keep the predicted electric power demand within the target electric power demand. A third calculating means, a fourth calculating means for obtaining a current power consumption suppression rate as a percentage from the third calculating means and the output of the first calculating means, and an output of the fourth calculating means. And a display means for displaying a percentage.