JPH0130371B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses as input the transmission pulse of a watt-hour meter with a transmitting device and the demand time signal of a demand wattmeter that outputs a demand time signal, and monitors the demand power so that the demand power does not exceed the contract power. This invention relates to a power demand monitoring instrument combined with a monitoring device.

Conventional power demand monitoring devices take as input pulses transmitted by a power meter with a transmitter, count these pulses to measure the power demand, multiply the increment in the power demand over a certain period of time by the remaining time of the demand time limit, and calculate this value. Calculate the predicted value of power demand by adding the power demand value at that point to the value, divide the difference between this predicted value and the target power demand by the remaining time of the demand period, and multiply this by a conversion factor to calculate the demand. There was one that calculated the adjusted power required for power control and displayed it together with the predicted value. When the predicted value exceeds the target power demand, a first stage alarm is generated, and when the adjusted value exceeds the desired power value, a second stage alarm is generated and load control is performed. The demand time limit is equipped with a time setting switch to synchronize with the electricity demand meter for transactions.When the time limit is set using this switch, from then on, the built-in clock circuit creates a time period of, for example, 30 minutes, and the time period is set for each monitoring time period. It was designed to monitor power demand.

However, since the monitoring time limit is created by a built-in clock circuit, the period between the demand time limit and the demand time limit will gradually deviate due to errors in the clock circuit or instrumental differences between the demand time device of the transaction demand meter and the transaction power meter. It won't fit. Therefore, there was a drawback that the monitoring of power demand was not accurate.

The present invention has been made in view of these drawbacks, and it measures the power demand by inputting the transmission pulse of the electricity meter with a transmitting device for transactions, and at the same time measures the demand time signal output from the electricity demand meter. It is an object of the present invention to provide a power demand monitoring instrument having a power demand monitoring device capable of always synchronizing the demand time limit of a trading power demand meter as an input.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment of the device according to the invention. 9
is a transaction instrument panel that houses the meters necessary for power transactions and detects the current of the sealed line by CT1 voltage with PT2, measures the amount of electricity from both by wattmeter with transmitter 3, and calculates the measured value. is output as the transmission pulse 4. This transmitted pulse 4 is input to a power demand meter 5, which will be described later, and the power demand is measured there. On the other hand, the transmitted pulse 4 is detected by a pulse detector 6, transformed into an electrically separated signal, and output as a transmitted pulse 8 from the pulse detector 6. The pulse detector 6 is capable of electrically isolating the emitted pulses 4 by picking them up using a through-type CT 6a. Reference numeral 5 denotes a demand power meter which is equipped with a demand time limit device and outputs a demand time limit signal 7 every time the demand time limit ends, for example, every 30 minutes, the details of which will be described later. Reference numeral 10 denotes a power demand monitoring device to be described later, which measures the power demand for each demand period by inputting the transmission pulse 8, calculates data necessary for the power demand based on this, and performs alarm generation load control and the like. Further, a monitoring time limit is also counted using the demand time limit signal 7 as an input, and the power demand is monitored using this monitoring time limit as one cycle.

Here, the power demand meter 5 will be explained with reference to FIG. 2 showing its details. In FIG. 2, 110 is a terminal for receiving the pulse 4 of the electricity meter with transmitter. Reference numeral 112 is a power demand counter for transactions, which counts pulses 4. Reference numeral 113 is a reference frequency transmitter for measuring the demand time limit. A clock section 114 measures the demand time limit by counting the reference frequency, and outputs a demand time limit end signal 115 every time the demand time limit ends. Demand time limit end signal 115
resets the demand power counter 112, and the demand power counter 112 restarts measurement of pulse 4 from 0. Reference numeral 116 denotes a monostable multivibrator which is triggered by the demand time limit end signal 115 and outputs a pulse having a width corresponding to a time constant determined by a resistor 117 and a capacitor 118. A transistor 120 amplifies this pulse and drives a solenoid 121 of the relay. 122 is a relay contact, which is closed while the solenoid 121 is energized. That is, at the end of the demand time limit, it is turned on for a certain period of time, and the above-mentioned demand time limit signal 7 is output from the output terminals T ₁ and T ₂ to output the demand time limit signal 7 to the demand power counter 12, reference signal generator 14, and demand time limit counter 15 shown in FIG. Reset each.

Next, one embodiment of the power demand monitoring device 10 will be described with reference to a block diagram. In FIG. 3, reference numeral 8 indicates a pulse transmitted from the trading instrument panel 9. Reference numeral 12 denotes a power demand counter for monitoring, which measures the power demand by counting the transmitted pulses 8. This count value is displayed by the power demand display section 13, and
The signal is input to the arithmetic circuit 17. Reference numeral 14 denotes a reference signal generating section for measuring the elapse of the demand time limit, which generates a signal with a constant period. Reference numeral 15 is a demand time limit counter that receives the reference signal and measures the remaining time of the demand time limit, and displays the counted value on the remaining time display section 20 and inputs it to the calculation line 17. 18, a target power demand setting unit sets a target power demand to be managed, for example, contract power. Reference numeral 19 denotes a control power setting section for setting the amount of load of a circuit whose load is to be controlled. Both set values are similarly input to the arithmetic circuit 17. The arithmetic circuit 17 receives the respective count values and set values as input and performs the following calculations, for example. The count value of the demand power counter 12 is P (kw), and the demand time period is T
(minutes), the count value of the demand time limit counter 15 when t (minutes) have passed since the start of the demand time limit, T-t (minutes),
The setting value of the target power demand setting unit 18 is Q ₁ (kw),
Assuming that the set value of the control power setting unit 19 is Q ₂ (kw) and the amount of increase in the demand power measurement value P for △t minute before t minute is △P, the demand power that will be reached at the end of the demand time period is The predicted value is R (kw), and the predicted value R (kw) = P + △P / △t (T - t) (kw)...(1
) can be calculated using the following calculation.

Also, from this predicted value, the load control amount required to reach the target power demand setting value Q ₁ is expressed as U (kw): Load control amount U (kw) = Q ₁ −R/T − tT (kw) ...(2) It can be obtained by the following calculation.

Both of these calculated values are displayed on the predicted power demand display section 21 and the control display section 22, respectively.

In addition, in the arithmetic circuit 17, the predicted power demand R
(kw) is compared with the target power demand set value Q ₁ (kw), and if the former exceeds the latter, a first stage alarm is generated and the alarm contact 23 is turned on. Similarly, the load control amount U (kw) is compared with the control power set value Q ₂ (kw), and when the first stage alarm is generated and either the former or the latter exceeds, the second stage alarm is generated and the alarm is activated. Turn on contact 24.

Reference numeral 7 denotes a demand time limit signal output from the demand wattmeter 5. This signal causes the reference signal generator 14, demand time limit counter 15, and demand power counter 12 to be reset, and a new demand time limit is started from that point. In this way, the 1
Since the predicted power, control amount, and remaining time are determined based on the two reference signals, each display section 21, 2
The displayed values of 2 and 20 are accurate without any time lag. Although the arithmetic circuit 17 operates as described above, it can be constructed relatively inexpensively and easily by using a microcomputer, for example.

Further, although one embodiment of the present invention has the above-mentioned configuration, it goes without saying that a configuration based on another system may also be used. In other words, instead of creating the cycle of the demand time limit yourself, resetting it for each cycle, and starting a new time limit from there, the demand time limit is determined by the signal from the electricity demand meter. That is, any power demand monitoring device that operates by inputting a power pulse from a power meter with a transmitting device and inputting a demand time limit from a power demand meter is sufficient.

It should be noted that the time signal of the power demand meter can be taken out without using a pulse detector as shown in FIG. 1, or it is of course possible to take out the time signal using a pulse detector.

Since the present invention is configured as described above, it is possible to eliminate the disadvantage of conventional devices in that the cycle of the monitoring time limit of the power demand monitoring device and the demand time limit of the demand power for trading is different and the power demand monitoring becomes inaccurate. This has the effect of improving the reliability of power demand monitoring.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a block diagram showing details of the power demand meter shown in FIG. 1, and FIG. 3 is a block diagram showing details of the power demand monitoring device shown in FIG. 1. In the figure, 3 is a power consumption meter with transmitter, 5 is a demand power meter, 6 is a pulse detector, 10 is a demand power monitoring device, 15 is a demand time limit counter, 17 is an arithmetic circuit, 20 is a remaining time display section, and 21 is a A predicted power demand display section (data display section), 22 is a control amount display section (data display section). Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A watt-hour meter with a transmitting device that generates a pulse signal according to the measured value of electric energy, a demand power counter for transactions that measures the above-mentioned pulse signal to measure the demand power, and a demand time limit signal that outputs a demand time limit signal every time the demand time limit ends. a demand power meter having a demand time limit device for outputting; a monitoring power demand counter that receives the demand time limit signal and measures the pulse signal to measure the demand power; and a demand power counter that receives the demand time limit signal and counts the demand time limit. a demand time limit counter, a calculation circuit that calculates data necessary for power demand monitoring based on the count values of the demand time limit counter and the monitoring power demand counter, and a data display unit that displays the calculation results. A power demand monitoring instrument characterized by comprising a power demand monitoring device.