JPS63240326A - Power demand monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a power demand monitoring device, in particular, monitors to ensure that the amount of power used during a demand period (for example, 30 minutes) does not exceed the contracted maximum power demand, and issues an alarm. Alternatively, the present invention relates to a power demand monitoring device that generates a control signal.

"Prior Art" Fig. 2 is a block diagram showing a conventional power demand monitoring device shown in, for example, Japanese Patent Publication No. 60-9412. In Fig. 6, (1) is a wattmeter with a transmitter; , whose input side is connected to PT and CT, and emits a pulse number proportional to the amount of power used.(2) is a current demand power counter.

One input side is a power meter with transmitter (1).

The other input side is connected to the first output side of the clock section (4), and the electricity meter with transmitter (1)
Count the number of emitted pulses. (3) is a demand power increment counter, one input side of which is the output side of the power meter with transmitter (1), and the other input side is the second output side of the clock section (4).

They are connected to each other, count the number of pulses during a certain period of time (Δt), and are reset to a certain period of time (Δt) by the output signal from this clock section (4). Also, at this time 3
The first part (4) counts the demand time period (T) and fixed time (1), and outputs a reset signal to reset the current demand power counter (2) and the demand power increment counter (3) at each time interval. do.

(5) is a remaining time counter, the input side of which is connected to the third output side of the clock section (4).

The remaining time (T-) of the demand time limit (T>) is counted based on the reference signal from the clock unit (4). <6) is a first arithmetic circuit whose first input side is the current demand power counter (2) whose second input side is the demand power increment counter (
3), whose third input is connected to the second output of the hour 31 section (4), and whose fourth input is connected to the output of the remaining time counter (5), respectively. Demand power (R
) is calculated based on the output signals of the current demand power counter (2), the demand power increment counter (3), and the remaining time counter (5) and the value of the constant time (Δshi). (7) is a target power demand setting device, which manually sets the demand power 1, for example, the contract power, to be 90 rin. (8) is a second arithmetic circuit whose first input side is the output side of the target power demand setting device (7) and whose second input side is the output side of the first arithmetic circuit (6). , the third input side thereof is connected to the output side of the remaining time counter (5), and the first arithmetic circuit (6) is connected to the output side of the remaining time counter (5).
), the predicted adjusted power (U5) is calculated based on the output signal of the demand power setting 2ii (7) and the remaining time counter (5) and the value of the demand time limit (T). (9) is an indicator,
Its input side is connected to the output side of the second arithmetic circuit (8) and displays the output value of the second arithmetic circuit (8), that is, the predicted regulated power (U8).

(10) is an alarm setting device, and the predicted adjustment power (U, l
), set the first alarm shift. (11) is a comparison circuit, one input side of which is connected to the output side of the second arithmetic circuit (8), and the other input side connected to the output side of the 7Jm setting device (10), Alarm setting device (10)
The warning u value from and the prediction 111 from the second arithmetic circuit (8)
1 Comparing with ffi electric power (U5), is this child? 1
When the 1q regulated power (Un) exceeds the 1-time alarm value, an alarm output signal is supplied to the alarm circuit (12) to alert the observer.

1. The power demand monitoring device at end C is configured as above,
Now, the predicted adjusted power (U,) is expressed by the following formula.

UR=T(R-Q)/T-(t+Δshi>...(1
)here.

T-demand time limit, 1=elapsed time, Δt=certain time before elapsed time (L), R=preliminary, 1t! l Demand power.

Q - Target power demand.

Further, the expected power demand (R) is expressed by the following formula.

R=P+ΔP/Δt(T-t,)・・・・・・・・・・・・
(2) 72 points.

P - Demand power at elapsed time (1) ΔP - Increase in power demand within eight areas △L goes through; W, goes +P) in about 1 to 5 minutes.

As expressed by the above equations (1) and (2), the t8 power until the end of the subsequent time period is determined from the average power and remaining time for the past ΔL minutes at a certain point in time.

The difference from the target power demand (Q) is calculated, and the second calculation circuit (
8) Prediction: Find the A rectification power (U,) and t! A ratio 1F2 circuit (11) compares the alarm value from the J report setting device 0) and this predicted adjusted power (U, l), and issues an alarm when the alarm value is exceeded.

[Problems to be solved by the invention] In the conventional power demand monitoring device as described above,
l Adjusted power (U,) is calculated from the average power during a certain time (△t), the remaining time (T-t,) and the target power demand (Q>, and the certain time (Δhi) is usually 1 Since it is more than 1 minute, the load fluctuation is within △.

The predicted adjusted power (which is determined from the current power used by Sada (hereinafter referred to as current power (P)) and the target time power (Q))
UR), and as a result an error occurs between l1t11. J
! There is a problem in that even if the load is cut off by J regulated power (UR), the target demand may not be met.

This invention has been made to solve this problem, and provides a power demand monitoring device that can ensure that the power demand falls within the target power demand (Q) when the load corresponding to the predicted adjustment power (U,) displayed by 1 is cut off. Obtaining is [1 target].

[Means for resolving the points in between] The power demand monitoring device according to the present invention inputs the voltage and the τB current detected from the PT and CT, respectively, and converts them into a voltage proportional to the electric power and a pulse proportional to the electric energy. a power converter to convert; 1 a counter that counts the number of pulses proportional to the power from the power converter; and an A/D conversion 2 to convert the voltage proportional to the power from the power converter into a digital value;
and a CPU that is interconnected with the counter and the A/D converter via a bus and issues output commands and performs predetermined calculations as necessary; and a CPU that is interconnected with the CPU and the bus via the bus. , a ROM that stores a program for operation commands, an rtAM that stores calculation results obtained by the CPU using data from the counter and the A/D converter, and a clock that calculates predetermined time data. It is equipped with a section.

[Operation] In this invention, a power converter and an A/D converter convert load current and load voltage into a current power value (P,).

[Embodiment] FIG. 1 is a block diagram showing an embodiment of a power demand monitoring device according to the present invention. In the figure, (138) is a power demand monitoring device, which is a power converter fA (14).

Counter (15), A/D converter (16), ROM
(17), RAM (18), clock section (1, 9), display IC (20>).

Display (21), CPU (22), load control circuit (2
3).

It consists of a data setter (24) and an alarm circuit (25). Of the above devices, all but one display (21) are interconnected via a data bus (26) and an address bus (27). (14) is a power converter,
Its input side is PT and CT.

Its output side is an A/D converter (16) and a counter.

They are connected to each other. Further, one display device (21) is connected to a display IC (20).

In the power demand monitoring device configured as described above, P
The voltage and current from T and CT are transferred to a power converter (14)
and are converted into a voltage proportional to the power and a pulse proportional to the amount of power.

A voltage proportional to electric power is input to an A/D converter (16), and a pulse proportional to electric power is input to a counter (15). The A/D converter (16) converts the input voltage into a digital value, and outputs the digital value to the data bus (26) when an output command is given to the CPU (22) via the address bus (27).

Similarly, the counter (15) accumulates the counted number of pulses and outputs the number of pulses to the data bus (26) according to a command from the CPU (2'). CPtJ (22) is flOM
(17) operates according to the program stored in the RAM (17), and in addition to interacting with the counter (15) and A/D converter (16) described above, various data are stored or stored in the RAM (18). Take out the date and calculate the elapsed time (t) and fixed time (Δt) using the clock part (1).
Data to be displayed (for example, adjusted power (UG) or remaining time (Tt, )) is sent to the display IC (20), and data to be set (for example, target power demand (T)) is sent to the data setting device (24). Q)), and also the current power (P,),
Calculate the regulated power (U,) and predicted demand power (R,) to determine whether or not there is an alarm, and if an alarm occurs, the alarm circuit (
25) generates an alarm, and the load control circuit (23) cuts off the load.

The predicted power demand (R,) is calculated using the following formula.

R≠p+P, (T-t,)/T・・・・・・・・・・・・
(3) Here, P=current power demand Po-current power T=time limit T-t=remaining time 1 hour is expressed in units of Hr.

Adjusted power (Ua) is expressed by the following formula based on this predicted power demand (fl,).

U, =T (R, -Q)/ (T-t) ・-...
...(4) Here, by calculating the above equations (3) and (4) with the CPU (22), r(, -Q = excess demand power), the accurate current power (P,) is calculated from the true current power (P,) Regulated power (Uo) can be obtained.

In the above embodiment, the pulse proportional to the electric power I input to the counter (15) is from the power converter (14). Good too.

[Effects of the Invention] As explained above, the present invention provides a method for converting the voltage and current detected from the PT and CT into a voltage proportional to the electric power and a pulse proportional to the electric power.
'JH, and a counter that counts the number of pulses proportional to the amount of electric power from the power converter.

an A/D converter that converts a voltage proportional to power from a power converter into a digital value; the counter and the A/D;
A CPU that is interconnected with the converter via a bus and issues output commands as necessary and performs predetermined calculations;
and are mutually connected via the bus □, and 1! The CPU uses data from the ROM storing the program for the h operation command, the counter, and the A/D converter.
1. The current power can be obtained by the built-in power converter 2; and the A/D converter,
You will no longer have to pay a large penalty fee for exceeding the contracted power with the power company due to incorrect power supply.

Additionally, for electric power companies, this has the effect of reducing load during peak hours.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a power demand monitoring device according to this embodiment, and FIG. 2 is a block diagram showing a conventional power demand monitoring device. In the figure, ri13^)...power demand monitoring device, (1
4)...Power converter, (15)...Counter, (1
6)...A/D converter, (17)...ROM, (
18)...RAM, (19)...Clock part, (20
)...Display IC, (21)...Display device, (22)
... CPU, (23) ... Load IJfl11 circuit,
(24)...Data setter, '(25)...Alarm circuit, (26)...Data bus, (27)...Address bus. Note that the same reference numerals in each figure indicate the same or corresponding parts. /￥+1 figure

Claims (1)

[Claims] A power converter that inputs the voltage and current detected from PT and CT and converts them into voltage proportional to electric power and pulses proportional to electric energy, and counts the number of pulses proportional to electric energy from the power converter. an A/D converter that converts a voltage proportional to the power from the power converter into a digital value; and an A/D converter that is interconnected with the counter and the A/D converter via a bus, a CPU that issues output commands and performs predetermined calculations, a ROM that is interconnected with the CPU via the bus and stores a program for operation commands, the counter, and the A/D.
It is equipped with a RAM that stores calculation results obtained by the CPU using data from the converter, and a clock unit that calculates predetermined time data, and the CPU calculates accurate time data using a predetermined calculation formula from the current electric power. A power demand monitoring device characterized in that it obtains adjusted power.