JPH0946901A - Demand control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excess of demand and thereby to prevent unnecessary 'tripping' of a 'circuit breaker' by outputting a tripping notice signal to a predetermined tripping from an estimate actual power computing circuit and an actual power detecting circuit. SOLUTION: The power of a 'circuit breaker' set beforehand is sampled. In the case when the power exceeds a guide line, an estimate power is determined by executing an arithmetic processing on the basis of the data on a demand elapsed time, an actual power and a contract demand, a final estimate power is estimated and the 'tripping' of the 'circuit breaker' is conducted on the basis of the estimation. According to this constitution, it is unnecessary to make the contract demand larger than the one needed actually and, besides, it is possible to give an advance notice of the time of the 'tripping' in the case when the guide line is exceeded. This enables execution of a preparatory operation for stopping safely a load system of the 'circuit breaker' to be 'tripped'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demand control device for preventing excess demand in a power reception and transformation monitoring system.

[0002]

2. Description of the Related Art For demand (demand forecast) control of a power receiving and transforming monitoring system, a guideline is set so that the actual power consumption falls within the contracted power, and a preset "cutoff" is set when the actual power consumption exceeds the guideline. "Cut off"
Was. Also, no "cutoff" notice was given.

[0003]

[Problems to be Solved by the Invention] If the guideline margin value is large, the demand may be exceeded. On the other hand, if the guideline margin value is small, unnecessary "breaker""breaker" is turned off. Was. Moreover, the "breaker" did not shut off after the "break" notice was issued.

The present invention prevents the demand from being exceeded by reducing the guideline allowance value, prevents unnecessary "breaking" of the "breaker", and issues an accurate "breaking" advance notice. It is an object of the present invention to provide a demand control device capable of performing the above.

[0005]

SUMMARY OF THE INVENTION A demand control device according to the present invention comprises a contract power input circuit for inputting contract power in advance, a demand elapsed time measuring circuit for measuring demand elapsed time, and power used for demand elapsed time in advance. Guideline to set Setting circuit, actual power consumption detection circuit to detect actual power consumption for demand elapsed time, and expected power calculation to calculate and predict power used during demand period from actual power consumption for demand elapsed time It is characterized in that it is provided with a circuit, and an interruption notice circuit for outputting an interruption notice signal to a predetermined circuit breaker from the expected use power calculation circuit and the actual use power detection circuit.

[0006]

In the demand control device of the present invention, the contract power is input in advance by the contract power input circuit, the demand elapsed time is measured, the power used for the demand elapsed time is preset, and the actual power used for the demand elapsed time is set. Detects and calculates the power used during the demand period from the actual power used with respect to the demand elapsed time, predicts it, and outputs the interruption warning signal to the predetermined circuit breaker from the expected power calculation circuit and the actual power detection circuit. It is characterized by that.

[0007]

EXAMPLE An example of the demand control device of the present invention will be described below. In FIG. 1, the contract power input circuit 11 is a circuit for inputting the contract power in advance. The demand elapsed time measuring circuit 12 is a circuit for measuring the demand elapsed time. The guideline setting circuit 13 is a circuit that presets the power used for the demand elapsed time. The actual power consumption detection circuit 16 is a circuit for detecting the actual power consumption with respect to the demand elapsed time. The expected power usage calculating circuit 14 is a circuit that is connected to the actual power usage detection circuit 16 and calculates and predicts the power used during the demand period from the actual power usage with respect to the demand elapsed time. The interruption notice circuit 15 includes a contract power input circuit 11, a demand elapsed time measuring circuit 12,
Guideline setting circuit 13, expected power calculation circuit 14
And a circuit that is connected to the actual power consumption detection circuit and outputs a breaking notice signal to a predetermined circuit breaker.

Next, in FIG. 2, the power consumption of a preset "breaker" is sampled, and when the guideline 2 is exceeded, the demand elapsed time T, the actual power consumption 3, the contract power Q. Based on the data, the expected power 4 is calculated, the final expected power Q _a is predicted, and the “breaker” is “interrupted”.

That is, first, a "breaker" preset
Find the load power of.

P _L = 〓3 × V × I × cos θ -------- (1) where P _L is the load power (kW) of the circuit breaker, V is the input voltage (V), and I is the input Current (A) and cos θ are power factors.

Next, the power reduced by the "breaker" being "cut off" is determined by the demand elapsed time T and the load power.

Q _L = (30−T) / 30 × P _L ------- (2) where Q _L is the reduced power (kW) and T is the demand elapsed time (min).

Then, the adjusted power is obtained. (And adjustment power, demand power meaning for timed termination actual power used during causes the same contract _{power) Q L = 30 / (30} -T) × (Q a -Q) ----- (3 ) However, P _C is the regulated electric energy (kWh), Q is the contracted electric power (k
W) and Q _a are final expected power (kW).

The timing of "shutoff" is that the demand does not exceed, and it is necessary to "shutdown" at the time when the following formula is established.

P _C ≧ P _L --------------------------- (4) However, due to the delay of the controller that performs calculation and processing, Considering the detection accuracy of the detector P _C = (P _L −β) ------------------- (5) where β is the bias (kW) .

Therefore, when the time from the time when the actual power consumption exceeds the guideline and the "breaker" needs to be "shutdown" to the "shutdown" is calculated, the shutoff timing is expressed by the equation (5). Substituting (3) from 1), 30 / {30− (T + t)} × (Q _a −Q) = {30−
(T + t)} / 30 × P _L t = 30−T− {30 × 30 × (Q _a −Q)} / P _L However, t is the cutoff notice time (minutes) until “cutoff”.

As described above, it is not necessary to increase the contracted electric power more than necessary, and when the guideline is exceeded, it is possible to give advance notice of the time of "cutoff", which means that
This means that preparatory work can be performed to safely stop the load system of the “breaker” that is “shut down”.

[0018]

According to the present invention, unnecessary "breaker""shutoff" and delay of "shutoff" prevent excess demand,
Also, there is an effect that the system can be safely stopped when "breaking" the "breaker".

[Brief description of drawings]

FIG. 1 is a configuration diagram of a demand control device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the operation of FIG.

[Explanation of symbols]

 11 Contract power input circuit 12 Guideline setting circuit 13 Demand elapsed time measuring circuit 14 Expected power calculation circuit 15 Interruption notice circuit 16 Actual power usage detection circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H02H 3/04 H02H 3/04 A 3/42 3/42 A

Claims (1)

[Claims] 1. A contract power input circuit for inputting contract power in advance, a demand elapsed time measuring circuit for measuring a demand elapsed time, a guideline setting circuit for presetting power used for the demand elapsed time, and the demand elapsed time. Actual power consumption detection circuit for detecting the actual power consumption, a predicted power calculation circuit for calculating and predicting the power used during the demand period from the actual power consumption for the demand elapsed time, and these predicted power calculation circuits And a cutoff notice circuit for outputting a cutoff notice signal from the actual power consumption detection circuit to a predetermined circuit breaker.