JPS5944855B2 - Demand power control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In order to prevent power demand from exceeding a target power demand, for example, contract power in power management, the present invention outputs a signal to perform load control when there is a risk of exceeding the target power demand, and performs load control. This relates to a power demand control device that controls power switches. Generally speaking, if the power demand exceeds the contract power, you will have to pay a relatively high penalty fee for the excess amount, so the power demand will exceed the contract power. If there is a risk of excess, it is necessary to know this in advance and prevent it from exceeding.

Conventionally, for this purpose, there has been a power demand meter with an alarm contact that generates an alarm when the demand power reaches a preset value, and thereby performs load shedding.

However, since this device generates an alarm regardless of the elapsed time of the demand time limit, many loads must be cut off when the elapsed time of the demand time limit is long. On the other hand, if the elapsed time is short, there are cases where it is not necessary to turn off the load again, which has the disadvantage that the optimum load control amount cannot be determined. In order to eliminate such drawbacks, the increment of power demand for a certain period of time is calculated, this value is multiplied by the remaining time of the demand period, and the current power demand value is added to this value to calculate the predicted power demand. Calculate the difference between this value and the target power demand, divide this by the ratio of the demand time period and the remaining time of the demand time period to calculate the adjusted power,
A device has been provided that performs load control based on this value. In other words, the system calculates the regulated power, which is a value that indicates how much load should be controlled, sets an alarm value for this value, and shuts off the circuit load one step at a time when the former exceeds this value. It was hot. However, this device has a drawback that when the power demand increases rapidly due to a sudden increase in load, the load control cannot keep up with the demand, and as a result, the power demand exceeds the target power demand. The present invention has been made in view of this point, and by setting an alarm value for the calculated regulated power, and when the regulated power exceeds the set value, the load of the number of circuits corresponding to the multiple of the set value is controlled. An object of the present invention is to provide a power demand control device that can keep demand monitoring power within a target power range even when power demand increases rapidly.

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes a power meter with a transmitting device that measures the amount of power in a circuit via a voltage transformer PT and a current transformer CT, and transmits a pulse signal proportional to the amount of power used. 2 is a counter that counts these pulses, and this count value is designated as P.

This value is reset to zero by a time limit end signal transmitted from the clock section 3 at the demand time limit T, for example, every 30 minutes. 4
is a counter that counts the increment Δp of the demand time limit, and the clock section 3
The signal is returned to zero at regular intervals Δt.

Reference numeral 5 denotes a subtraction counter that counts the reference pulse from the clock section 3 to count the remaining time T-t, which is the difference between the demand time limit T and the demand time limit excess time TO.

6 is a setting unit that sets the target power demand Q.

7 is an arithmetic circuit that calculates the adjusted power based on the above-mentioned count value and setting value, and specifically, it calculates the following equation.

In other words, it can be obtained by letting U be the adjusted awakening force.

Here, Q: Target demand power, P: Demand power at demand time t, Δp: Increment of demand power at time Δt, T-
t: Remaining time of demand time limit, T: Demand time limit (for example, 30 minutes). 8 is a display unit that displays the adjusted power U calculated by the above equation (a).

9 is an indicator of the polarity of the regulated power U. According to the above equation αa), when the regulated power U is positive, the demand power is unlikely to exceed the target power demand Q, and when the regulated power U is negative, the demand is This indicates that the power is likely to exceed the target power demand Q.

Therefore, when the regulated power U is negative, it is necessary to cut off the load, and when the regulated power U is positive, it indicates that there is room to turn on the load. However, if the load is simply controlled, the load may be turned off or turned on too much, or the load may be controlled too frequently, which may shorten the life of the load switch. 10 is a setting device for setting an alarm value V for the regulated power U. This is to provide a certain dead zone so that load control will not be performed unless the absolute value of the adjusted power U exceeds a certain value even if the polar range is negative, and this set value is the load capacity for one load control. All you have to do is set . That is, the regulated power U
When exceeds this value, load control is performed. 1
4 is a first division circuit that divides the value of the adjusted power U by a certain natural number, for example, 2.

Reference numeral 15 denotes a gate circuit, which allows the output of the first division circuit 14 to pass when the polar range of the regulated power U is positive, and passes the output of the arithmetic circuit 7, that is, the value of the regulated power U, when the pole l is negative. This is the switching operation that allows the

A second division circuit 11 divides the value passed through the gate circuit 15 by the alarm value V, obtains the quotient, and outputs the integer part of the quotient.

Then, the load of this quotient number is controlled. Reference numeral 12 denotes a load control circuit, which controls the load twice if the quotient is 2, and controls it three times if the quotient is 3, for example.

For example, it is composed of a relay circuit. Right load control circuit 13
A load equal to the value of the alarm value V is connected to each terminal. Next, the polar bend of the regulated power U and the first division circuit 1
4 and the operations of gate circuit 15 will be explained in detail.

If the display value of the extreme area indicator 9 is negative, it is assumed that the demand power is likely to exceed the target demand force Q, and it is necessary to perform load shedding. The gate circuit 15 passes the output of the arithmetic circuit 7 based on this extreme signal, inputs it to the second division circuit 11, divides the adjusted power U÷the alarm value V, and divides the load equal to the number of integer parts of the quotient. shut off and reduce power consumption. Next, when the display value of the extreme area indicator 9 is positive, it indicates that there is no fear that the power demand will exceed the target power demand Q, and that there is a margin for the power consumption. Therefore, if you want to use electricity efficiently at the very limit of the target demand power, you can increase the power usage by adding a load. However, if a load is applied in the same manner as load shedding, there is a risk that the load may have to be immediately shelved due to load fluctuations. This is undesirable because it shortens the life of the load switch. Therefore, when the polarity is positive, the gate circuit 5 passes the result of dividing the adjusted power U by any natural number n in the first division circuit 14, and inputs it to the second division circuit 11 in the same manner as above. , and a load equal to the integer part of the quotient is applied to increase the power consumption. Since the amount of load that is applied is less than the amount of load that is cut off, the number of times that the load has to be cut off again is reduced, and moreover, electricity can be used more efficiently. Although one embodiment of the present invention has the above-mentioned configuration, if the divisor n of the first division circuit 14 is configured to have a preset means that can be set arbitrarily, load application when there is a margin in the demand power is possible. Since the frequency can be set arbitrarily by the user, the effect is extremely large.

Further, it is also possible to configure the system so that the load is applied at all points when the demand time period ends, and the load control operation as described above is performed below. Alternatively, the numerator may be calculated as Δp {P+-(T-t)}-Q in the arithmetic expression, and the meanings of "+" and "-" displayed on the polar Δt area display 9 may be reversed.

In addition to △p of the adjusted power display 8, a display may be provided to display P+1(T-t)△t corresponding to the predicted power demand, the demand power P at the demand time limit t, and the remaining time (T-t). is also possible.

In addition, the arithmetic circuit 7 and the first and second division circuits 14 and 11
can be constructed using general-purpose C, but it can also be constructed using an arithmetic element such as a microcomputer. It is also possible to replace the demand power counter 2, the demand power increment counter 4, and the remaining time subtraction counter 5 with the memory of the microcomputer. Furthermore, in the above embodiment, the first division circuit 14 is arranged before the second division circuit 11, but as shown in FIG. It is also possible to arrange a divider circuit, switch it in the gate circuit 15 according to the range signal, and input it to the load control circuit 12.

Moreover, the calculation formula for calculating the adjusted power is not based on the above-mentioned formula (a), but can also be calculated using the following formula (b). That is, here, Q: target power demand, P: power demand at demand time limit t, Δp: increment of power demand at time Δt, T-t
;Remaining time of demand time limit, T;Demand time limit (for example, 30 minutes)
It is. Next, to explain the physical meaning of equation (b), the first term is to calculate the difference between the target power demand Q and the power demand P at time period t using the equation (Q-P), and calculate this for the remaining time of the demand time period ( The electric power that can be used in the time limit t, that is, the allowable electric power, is obtained by dividing the ratio of T-t) to the demand time limit T.

And the second term is the increase in demand force (△p) (Δt/T)
By dividing by , the instantaneous average power in time period t is obtained. This is based on the principle that the adjusted power is determined by the difference between the two. On the other hand, equation (a) is {P+for(
The adjusted power is calculated by subtracting the difference between the predicted power demand Δt and the target power demand, expressed by the formula T-t), by the ratio of the remaining time (T-t) and the demand time limit T, and as a result, Will it be the same formula? The way of thinking is completely different, and the circuit configuration will naturally be different.

As described above, according to the present invention, an alarm value is set for the adjusted power calculated, and when the adjusted power exceeds the set value,
Since the configuration is configured to control the load of the number of circuits corresponding to a multiple of the number of circuits, it is possible to accurately perform the load control necessary to keep the power demand within the target power, which has the effect of enabling efficient power use. In today's situation where energy saving and resource saving are in demand, the effects of the device of the present invention are extremely remarkable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. In the figure, 1 is a power consumption meter with a transmitter, 2 and 4 are counters, 3 is a clock section, 4 is a subtraction counter, 6 is a setting section, 7 is an arithmetic circuit, 8 is a display section, 9 is an indicator, and 10 is a Setting device, 1
4 and 11 are first and second division circuits, 12 is a load control circuit, and 15 is a gate circuit.

Claims (1)

[Scope of Claims] 1. Count the pulses transmitted by a power meter with a transmitter that transmits pulses proportional to the amount of electric power, and calculate the counted value, the increment of the counted value within a certain period of time, the demand time period, and this demand time period. The first step is to calculate the adjusted power from the remaining time and the target power demand.
means for displaying the regulated power; third means for setting an alarm value for the regulated power; fourth means for dividing the regulated power by a predetermined multiple of the alarm value to obtain an integer part of the quotient when the arithmetic code is different from the predetermined polarity; When the polarity is the predetermined polarity, the number of load circuits corresponding to the output of the fourth means is cut off, and when the operational sign is different from the predetermined polarity, the number of load circuits corresponding to the output of the fourth means is cut off. A demand power control device comprising a fifth means for controlling input. 2 The first means is U=(Q-{P+(△p/△t)(T-t)}/(T-
t)/T) where U: Adjusted power, Q: Target demand power, P
; Demand power at demand time limit t, Δp; Increment of demand power at time Δt, T-t; Remaining time of demand time limit, T;
2. The power demand control device according to claim 1, wherein the power demand control device performs calculation of demand time limit. 3 The first means is U={P+(△p/△t)(T-t)}-Q/(T-t
)/T) Here, U: Adjusted power, Q: Target power demand, P
; Demand power at demand time limit t, Δp; Increment of demand power at time Δt, T-t; Remaining time of demand time limit, T;
2. The power demand device according to claim 1, wherein the power demand device calculates a demand time limit. 4 The first means is U = (Q-P/(T-t)/T)-(△p/△t/T)
Here, U: Adjusted power, Q: Target power demand, P: Demand power at demand time limit t, Δp: Increment of demand power at time Δt, T-t: Remaining time of demand time limit, T; Claim 1, characterized in that a calculation of demand time limit is performed.
Demand power control device as described in section. 5. A fourth means includes a first division circuit that divides the regulated power by a predetermined natural number, and makes the regulated power valid when the arithmetic sign of the regulated power has a predetermined polarity, and the regulated power is different from the predetermined polarity. A gate circuit that validates the output of the first division circuit, and a second division circuit that divides the output of the gate circuit by an alarm value and obtains the integer part of the quotient. The power demand control device according to any one of the ranges 2 to 4. 6. The fourth means includes a second division circuit that divides the adjusted power by the alarm value and obtains an integer part of the quotient, and a first division circuit that divides the output of the second division circuit by a predetermined natural number. , comprising a gate circuit that validates the output of the second division circuit when the operational sign of the adjusted power has a predetermined polarity, and validates the output of the first division circuit when the operational sign of the adjusted power differs from the predetermined polarity. A power demand control device according to any one of claims 2 to 4, characterized in that: