JPH0290064A - Demand monitoring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform elaborate monitoring and to perform monitoring with enough time by comparing a predicted demand with a warning line, and generating warning when the demand exceeds the warning line. CONSTITUTION:A warning line which is set in correspondence with the transition of loads is compared with a demand for electric energy computed in an operating part 3 based on the detected electric energy pulse that is detected with a pulse detecting part 1 in the operating part 3. When the demand exceeds the warning line, the warning is issued through a warning output part 7, and a load 11 is cut off through a load opening and closing part 9. When the warning line is set in correspondence with the transition of the loads, the long continuation of the generation of the warning is avoided even if the demand exceeds the warning line temporarily and the warning is issued at the beginning half period wherein many loads are used as in a conventional apparatus. The pattern of the warning line is set by estimating the pattern so that the pattern is close to the transition of the actual load. It is desirable that the pattern is set upon grasping the changes in, e.g. time zones and every day of the week.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a demand monitoring device that monitors changes in demand for electric power and issues an alarm when the demand exceeds a predetermined alarm line. Regarding.

(Prior Art) In a conventional demand monitoring device, an alarm line is shown as a straight line 23, for example, as shown in FIG. 4(a). More specifically, in FIG. 4(a), the horizontal axis shows the demand monitoring time of 30 minutes, the vertical axis shows the electric energy, the change in demand during the demand monitoring time is shown as a demand curve 21, and the alarm line is drawn as a straight line 23. It is shown in Then, when the demand indicated by the curve 21 exceeds the alarm line indicated by the straight line 23 at time t1 as shown in the figure, an alarm is generated, and this alarm is generated while the demand curve 21 exceeds the alarm line 23.

In Fig. 4(a), the usable demand is, for example, up to 1,500 kW, but in contrast, the demand actually used is generally such that a large amount of load is used in the first half, as shown in demand curve 21 in the figure. , the second half is not used much, so even if the linear alarm line 23 shown in FIG. 4(a) does not exceed the demand target value within the monitoring time, the demand curve 21 may exceed it during the first half. As a result, the alarm will be issued for a long time.

On the other hand, as shown in FIGS. 4(b) and (C), a possible method is to make the alarm line nearly horizontal as shown by the straight line 23 so that the demand does not exceed the alarm line in the first half. However, as shown in FIG. 4(b), the period 25 from the intersection of the demand prediction curve 24 shown by a dotted line and the alarm line to the load shedding is calculated by extending the demand curve 21 several minutes after the start of demand. Since the intersection point in the above case occurs at a place where the demand value is high, there is no margin for monitoring. Further, as shown in FIG. 4(C), if an alarm occurs several minutes after the start of the demand, there is not much power available for the remaining time, so there is no margin and there is a risk that the contracted power amount will be exceeded.

Furthermore, with conventional devices, it is not possible to predict how much load can be used each time an alarm occurs.

Furthermore, it is impossible to predict how long it will take for the load to be used once the load is cut off, so when an alarm occurs, it is necessary to take measures to cut off the load immediately.

(Problems to be Solved by the Invention) As mentioned above, in a conventional linear alarm line, if a large load occurs in the first half, alarms may continue to occur for a long time or monitoring may not be possible. However, there is a problem in that there is a risk that the contracted power amount will be exceeded.

The present invention has been made in view of the above, and its purpose is to provide a demand monitoring device that performs detailed demand monitoring based on an alarm line that is close to the actual load transition.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object 1, the demand monitoring device of the present invention monitors the demand for electric energy, and when the demand exceeds a predetermined alarm line, the demand monitoring device generates an alarm. The monitoring device includes an alarm line storage means for storing a demand alarm line pattern on the pf side so as to be close to the actual load transition, and a demand alarm line storage means for storing the demand alarm line pattern on the pf side so as to be close to the actual load transition, and calculating the demand that changes according to the actual load change. At the same time, a demand calculation means for calculating one line of pre-pulmonary lung for the demand, and a demand calculated by the demand calculation means are compared with the alarm line stored in the alarm line storage means, and the demand is calculated from the alarm line. The gist of the invention is to have an alarm generating means that issues an alarm when the limit is exceeded.

(Function) The demand monitoring device of the present invention compares the demand that changes in accordance with changes in the actual load with a demand alarm line that is pre-DI'd so that it is close to the change in the actual load, and when the demand exceeds the alarm line. An alarm is generated when

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram showing the configuration of a demand monitoring device according to an embodiment of the present invention. The demand monitoring device shown in the figure includes a pulse detection unit 1 that detects electric energy pulses, and an alarm line storage unit 5 that stores demand alarm lines that have been previously set to approximate the actual load transition. Then, the demand for electric energy is calculated based on the electric energy pulse detected by the pulse detection section 1, and this demand is compared with the alarm line stored in the alarm line storage section 5 to determine whether the demand matches the alarm line. an arithmetic unit 3 that outputs an alarm command signal when the alarm exceeds the limit; and an alarm output unit 7 that outputs an alarm signal based on the alarm command signal from the arithmetic unit 3;
It has a load switching section 9 that opens and closes the load 11 based on the alarm signal output from the alarm output section 7.

Next, the operation when a plurality of loads are continued as shown in FIG. 2 will be explained with reference to the graph in FIG. 3.

First, the contract power is 900 kW and the demand time is 30 kW.
minutes, the demand measurement interval is 10 seconds, and the loads are general load (300kW), load A (
500kW), load B (5(,)OkW), load C (5
00kW), load D (200kW), load E (20
0kW), load F (200kW) is connected, the general load operates from the start of demand to the end, load A operates for 5 minutes from the start of demand, and load B operates for 1 minute from the start of demand.
Let us consider the case of a consumer who uses the load in such a way that the load is in operation for 0 minutes and the load C is in operation for 15 minutes from the start of the demand.

In response to such changes in load, in this example, 350 kW is generated 5 minutes after the start of the demand, and 6 kW after 10 minutes.
The alarm line is set to 50 kW, 700 kW after 15 minutes, and 900 kW after 130 minutes, and this alarm line is stored in the alarm line storage section 5. This alarm line becomes alarm line 13 in FIG. 3(a).

Alarm line 1 is set according to load changes in this way.
3 and the power demand calculated by the calculation unit 3 from the power pulse detected by the pulse detection unit 1, and if the demand exceeds the alarm line 13, an alarm is issued via the alarm output unit 7. occurs, and the load switching section 9
By setting the alarm line 13 according to the load transition as described above, the demand 15 is reduced in the first half when a large number of loads are used as in the conventional case, as shown in Fig. 3(b). Even if the alarm line 13 is temporarily crossed and an alarm is generated as shown in the period 21-, as shown in FIG. In a), the demand curve shown by the solid line 15 is extended like a dotted line to obtain the predicted line 17, and the time from the intersection of the two where this predicted line 17 crosses the alarm line 13 to the load shedding can be obtained. , it is possible to have leeway in monitoring demand. For example, if the time until load shedding is 4 minutes when the demand starts at 3 minutes, it can be seen that there is a margin until load A is shut off after 2 minutes. Also, if the time until load shedding is 1 minute when the demand starts 3 minutes, it is understood that there is no margin and it is necessary to perform control such as shutting off other loads D-F. .

It should be noted that the pattern of the alarm line is set in advance to match the actual load transition, but it is preferable to set this after understanding the changes, for example, depending on the time of day or day of the week. Furthermore, another method may be to store past demand curves, set this stored curve as an alarm line, and perform monitoring while comparing.

Furthermore, when the demand curve exceeds the alarm line and the load is cut off, it is also possible to calculate at what point the alarm can be canceled and the load can be turned on again.

〔Effect of the invention〕

As explained above, according to the present invention, demand that changes in accordance with changes in actual load is compared with a demand warning line predicted in advance to be close to the actual load transition, and the demand exceeds the warning line. Since the alarm is generated when the load is exceeded, detailed monitoring is possible, and the alarm does not occur in the first half of the day when a large amount of load is used and does not continue for a long time, which is the case with conventional methods, and monitoring can be carried out with more time. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a demand monitoring device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the configuration of a load used to explain the operation of the demand monitoring device of FIG. 1. , FIG. 3 is a graph showing the demand curve and alarm line used in the demand monitoring device of FIG. 1, and FIG. 4 is a graph showing the demand curve and alarm line in the conventional demand monitoring device. DESCRIPTION OF SYMBOLS 1... Pulse detection part, 3... Calculation part, 5... Alarm line storage part, 7... Alarm output part, 9... Load switching part, 13... Alarm line, 15... demand curve.

Claims (1)

[Claims] A demand monitoring device that monitors the demand for electric power and issues an alarm when the demand exceeds a predetermined alarm line, and predicts the pattern of the demand alarm line in advance so that it is close to the actual load transition. an alarm line storage means for storing the demand, a demand calculation means for calculating a demand that changes according to changes in actual load and a predicted line of the demand, and an alarm line storage means for storing the demand calculated by the demand calculation means. 1. A demand monitoring device comprising: alarm generation means for comparing the demand with the alarm line stored in the means and generating an alarm when the demand exceeds the alarm line.