JPS6118770B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a demand control device that controls the amount of power used during a demand period (for example, 30 minutes) so that it does not exceed the contracted maximum amount of power demand.

A demand control device receives pulses from a power meter with a transmitting device, and calculates the current value of power consumption, predicted value at the end of the demand period, corrected value of power at present, etc. from the number of received pulses. However, since the amount of power per input pulse to the demand control device is fixed,
If the PT ratio, CT ratio, or pulse constant is changed due to a contract change or a meter change, there is an inconvenience that the demand control device cannot be used as is. Also, the synthesis metamorphic ratio and pulse constant may differ depending on the industry, so
It was necessary to separately manufacture a demand control device for that industry.

The purpose of the present invention is to provide a versatile demand control system that can easily handle cases where the composite transformation ratio or pulse constant changes after installation, or where the composite transformation ratio or pulse constant differs depending on the type of industry. The purpose is to provide equipment.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a demand control device 1. The demand control device 1 measures the amount of power used by a load 2 and receives pulses from a power meter 3 with a transmitting device that transmits pulses proportional to the measured value. . PT is a potential transformer and CT is a current transformer. The composite transformation ratio setter 4 sets the composite transformation ratio of the potential transformer PT and the current transformer CT.
As an example, the figure shows PT66000/110V, CT ratio
200/5A, composite metamorphic ratio (66000÷110)×200÷5)
=24000 value is shown. The pulse constant setter 5 is used to set the pulse constant of the power meter 3 with a transmitting device, and FIG. 1 shows an example of 2000 pulses/KWH. The amount of electric power per pulse is (synthetic transformation ratio/pulse constant). The pulse number conversion circuit 6 multiplies the number of pulses input from the power meter 3 with transmitting device by (synthetic transformation ratio/pulse constant) and inputs the result to the current counter 7 and the sampling value counter 8. The current value counter 7 counts the output pulses of the pulse number conversion circuit 6 and measures them as the current value _W1 of the amount of power used in the demand time period T. If the demand time limit T is 30 minutes, simply counting the number of output pulses from the pulse number conversion circuit 6 will yield a unit of KWH, so double the counted value to obtain KWT (T=30 The unit is minutes).
The current value display 9 displays the current value _W1 . The sampling value counter 8 converts the output pulses of the pulse number conversion circuit 6 into sampling times Δt (for example, 1 minute, 3
minutes, etc.), and calculate the amount of electricity used per unit time (1 minute, etc.).
Measure the sampling value △W/△t per minute).

The remaining time clock circuit 10 generates the remaining time (Tt) of the demand time limit T (t is the current time), and the remaining time display 11 displays the remaining time (Tt). Multiplier circuit 1
2 is the sampling value △W/△t and the remaining time (T-
t) to calculate the amount of power △W/△t× if the current power usage continues for the remaining time (T-t)
Calculate (T-t). The adder circuit 13 outputs the current value W ₁
and △W/△t×(T-t) to obtain the predicted value of the amount of power used at the end of the demand period T.
Calculate Wx. The predicted value Wx is displayed by the predicted value display 14.

The target value setter 15 sets a target value Wb of the amount of power used at the end of the demand time period T. The subtraction circuit 16 subtracts the target value Wb from the predicted value Wx, and when the difference becomes positive, that is, when the predicted value Wx exceeds the target value Wb as shown in FIG. 2, it operates the alarm display circuit 17. Sound a buzzer, etc., and turn on or flash a warning light or other indicator. The multiplication/division circuit 18 calculates the correction value Px=T(Wx
−Wb)/T−t). The correction value Px is the amount of electricity used at the end of the demand time period T and the target value
This means the load capacity that should be cut off or turned on within the remaining time (Tt) in order to match Wb, and is displayed by the correction value display 19.

The shear failure recovery value setter 20 is used to set the width of the correction value Px when the load is cut off or applied.The correction value Px is compared with the shear failure recovery value in the comparison circuit 21, and a positive correction is made. When the value Px exceeds the failure recovery value, the load control circuit 22 operates and the load 2
cut off a part of the Also, the negative correction value Px
When the voltage exceeds the disconnection recovery value, the load control circuit 22 turns on a part of the load 2 that has been disconnected.

After the installation of the demand control device 1, the synthesis transformation ratio and pulse constant may change due to a change in the contract or the meter, or before the installation of the demand control device 1, the synthesis may vary depending on the industry. If the setting values of the composite transformation ratio setter 4 or pulse constant setter 5 are adjusted to the transformation ratio and pulse constant, the amount of power per pulse output by the pulse number conversion circuit 6 will be fixed. Therefore, the demand control device 1 can be used as is.

In FIG. 1, the pulse number conversion circuit 6 includes a current value counter 7 and a sampling value counter 8.
However, at any stage inside these counters 7 and 8, the number of pulses from the electricity meter with transmitter 3 is multiplied by (synthetic transformation ratio ÷ pulse constant). It can also be connected to.

The present invention includes a composite transformation ratio setter that sets the composite transformation ratio of an instrument transformer and a current transformer, a pulse constant setter that sets the pulse constant of a power meter with a transmitter, and a current value counter and a sampling Since it is equipped with a pulse number conversion circuit that multiplies the number of pulses from the watt-hour meter with a transmitting device by (synthetic transformation ratio ÷ pulse constant) at any stage from the stage before the input of the value counter to the inside of the counter, Even if the composite transformation ratio or pulse constant changes after installation, or if the composite transformation ratio or pulse constant differs depending on the type of industry, it can be easily accommodated and has versatility.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram showing a time-power amount characteristic curve. DESCRIPTION OF SYMBOLS 1... Demand control device, 3... Electric energy meter with pulse transmitting device, 4... Synthetic transformation ratio setting device, 5...
Pulse constant setter, 6...Pulse number conversion circuit, 7...
Current value counter, 8...Sampling value counter,
10... Remaining time clock circuit, 12... Multiplication circuit, 13...
Addition circuit, 15...Target value setter, 16...Subtraction circuit, PT...Instrument transformer, CT...Current transformer, W ₁ ...Current value, △W/△t...Sampling value, △t...Sampling time, T ...Demand time limit, t...Current time,
Wx...Predicted value, Wb...Target value.

Claims (1)

[Claims] 1. A current value counter that measures the current value of the amount of power used during the demand period based on the number of pulses from the watt-hour meter with a transmitter, and a current value counter that measures the amount of power used per unit time during the sampling period based on the number of pulses from the watt-hour meter with the transmitter. a sampling value counter for measuring the sampling value of the transformer; a composite transformation ratio setting device for setting the composite transformation ratio of the instrument transformer and the current transformer; and a pulse constant setting device for setting the pulse constant of the electricity meter with transmitter. , a pulse number conversion circuit that multiplies the number of pulses from the watt-hour meter with transmitter by (synthetic transformation ratio ÷ pulse constant) at any stage from the stage before the input of the current value counter and the sampling value counter to the inside of the counter. , a remaining time clock circuit that indicates the remaining time of the demand time limit, a target value setter that sets the target value of the power consumption at the end of the demand time limit, and a remaining time clock circuit that indicates the remaining time of the demand time limit, a target value setter that sets the target value of the power consumption at the end of the demand time limit, and a A demand control device that includes an arithmetic circuit that predicts power consumption and compares the predicted value with a target value.