JPH07112332B2 - Maximum demand power monitoring controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a maximum demand power monitoring control device for monitoring and controlling the maximum demand power contracted by a power consumer with a power supply company.

[Conventional technology]

Usually, large-scale power consumers monitor and control the maximum demand power contracted with the power supply company, and adjust the load so that the contract power is not exceeded. Here, the demand power is the average value of the power consumption during a certain period of time, and the maximum demand power is the maximum demand power during the demand time.

In other words, the maximum demand power meter is set so that the contract power (that is, the average power value within an arbitrary T time, where T = demand time) is not exceeded during the contract period. The electric power consumer is monitored by (a device that detects the average electric power within the T time and records the maximum value at every T time).

Conventionally, as the maximum demand power adjustment device (method), in order to keep the maximum demand power within a predetermined value, when the power consumption from the start time of a demand time to a specific time is detected and the demand power at that time is continued as it is, A value obtained by removing the difference between the expected power amount and the set power amount in the remaining demand time is calculated as the adjusted power, or the difference between the demand power at a specific time and the power available in the remaining time is used as the adjusted power. Calculate and compare the adjusted power with the control set value, and adjust the load based on the excess and deficiency. Alternatively, means such as detecting the average power used from the start time of the demand time to a specific time and the power used at that time and calculating the excess power for the contracted power to obtain the adjusted power are used or proposed. It was

As described above, in the conventional maximum demand power monitoring control device, in any case, the command time limit of the maximum demand power meter for transaction and the demand time limit of the maximum demand power adjusting device need to be always synchronized.

[Problems to be solved by the invention]

Since the conventional maximum demand power adjustment device is configured as described above, the demand time limit of the maximum demand power meter for transaction and the time limit of the maximum demand power adjustment device must always be synchronized, and therefore various operational points are required. There was a problem. In other words, the maximum demand electricity meter for transaction is sealed and the electric power company owns the property, so that the demand time period synchronization is easy even though the demand time period synchronization is important. In addition, it took time and effort to correct the mutual error on a regular basis, which hinders the labor saving of control and monitoring. In addition, the contract power should be contracted with a margin for the error compared to the power used. There was a problem such as.

The present invention has been made to solve the above problems, and it is possible to keep the maximum demand power within the contract power without synchronizing the demand time limit of the maximum demand power meter for transaction and the maximum demand power adjusting device. It is possible to reduce the value of the contract power because the difference between the contract power and the demand power can be brought closer to the contract power by a margin as much as the difference between the contract power and the demand power unlike the conventional one. The purpose is to obtain a maximum demand power adjustment device that can be used.

[Means for solving problems]

The maximum demand power monitoring control device according to the present invention detects the average power up to the present time from the time traced T × K (K is a proportional constant) before the demand time T from the present time, and detects this moment by moment. Keeping in mind that the maximum demand electricity meter for transactions will not exceed the contract value if the detected average power value does not exceed the contract electricity, synchronize with the demand time of the maximum demand electricity meter for transactions. Instead, the maximum demand power can be monitored and controlled.

[Action]

The maximum demand power monitoring and control device according to the present invention detects the average power every moment and also detects the average power according to the demand characteristics of the maximum demand power meter for transaction and the instantaneous power at the present time. The output of the instantaneous power detector controls the load under the condition that the average power has reached a predetermined value with respect to the contract power, and the current instantaneous power exceeds the set predetermined value for a predetermined time or more. The maximum demand power is monitored and controlled.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.
In the figure, 1 is an instrument transformer (hereinafter referred to as PT) for measuring electric power, 2 is an instrument current transformer (hereinafter referred to as CT), and 3 is PT.
1, a power converter that measures power from CT2, 4 is an instantaneous power detector that detects the magnitude of the instantaneous output of this power converter 3, 5 to 7,
9 is an average power calculation unit. Reference numeral 5 is an analog-to-digital conversion unit (hereinafter referred to as A / D conversion unit) that converts the analog output of the instantaneous power of the power converter 3 into a digital amount at each sampling time, and 6 is a memory circuit, and a digital amount at each sampling time Is stored for each unit time. 7 is a timer for sorting out 6 memories that have passed the demand time T × K or more, 8 is a setting unit of the contract power value, 9 is the sum of 6 memories within the demand time T × K in the demand time T × K 10 is a calculation unit that calculates the average value by dividing every unit time every moment, 10 has reached the range where the average power value is less than the contract power value and more than the set value set below the contract power value Distinguishing unit that determines whether or not the average power value is greater than or equal to the set value and the instantaneous power value exceeds the contract power value The logic unit 11 having an output unit is a load that controls the maximum power demand.

Next, the operation will be described.

In FIG. 1, the instantaneous power is detected by the power converter 3 by PT1 and CT2, and one of the outputs is detected by the instantaneous power detector 4 and input to the logic unit 10. The other one is that the A / D converter 5 converts the analog amount detected by the power converter 3 into a digital amount in each unit time, and the converted digital amount is stored in the memory circuit 6 in each memory unit. Let the memory. This memory unit 6
If the demand time of the transaction power meter is T, then the memory is reset sequentially when T × K (K is a proportional constant 0 <K1), and a new digital amount per unit time is memorized. Let Then, the total sum of the digital amounts stored in the computing unit 9 is calculated as T for each unit time.
By dividing by × K, the average power can be detected every unit time. This average power value is input to the logic unit 10.

Further, the contracted power value is input from the contracted power setting unit 8 to the logic unit 10.

Next, the relationship between the contract power and the change in the detected average value and the change in load will be described with reference to FIG. In the figure, the horizontal axis represents time and the vertical axis represents power value. WB is the contract power, the instantaneous power is the power at time t ₁ , W ₁ at t ₂ , W ₂ at t ₃ ,
If W ₃ , t ₄ and W ₄ , t ₅ are W ₅ , the average power value WA changes as shown in FIG.

At the time t _4, the instantaneous power becomes W ₄ , and at t ₅ , the average power with respect to WB is determined by the determination unit to reach WB minus ΔW. Then, by controlling the load of A plus WK (however, WK and ΔW are arbitrary values that are optimally adjusted in consideration of individual load fluctuations of customers), control is performed so as not to exceed the contract power WB. It is what makes me.

That is, there is a possibility that the average power value exceeds the contract power value under the condition that the average power value WA or the contract power value WB reaches a set value of minus ΔW value and the instantaneous power value exceeds the contract power value WB. The control output or display is performed so as to predict and limit the overload on the consumer side in proportion to the excess power value in which the instantaneous power value exceeds the contract power value. The ΔW value may be increased for a consumer who has a large load fluctuation, and the A value may be increased. Further, if the K value of T × K approaches 0, it approaches the instantaneous power value, and it is possible to deal with a load in which the load changes drastically. That is, assuming that the instantaneous power changes from 0 to W and is constant as it is, the time for detecting the average power value W when K = 1 is T, and the average power value W is the time T from the detection of the instantaneous power value. Be late.

FIG. 3 shows a process of momentarily calculating the average power of the instantaneous power WI. The instantaneous power is converted into a digital amount for each sampling time Δt, which is stored in the memory 6.
M ₁ to Mn is respectively memory until, the average power value at Tn the sum total of the arithmetic unit 9 is divided by T × K. When Tn _+1, the average value of M _{2 to} Mn ₊₁ is calculated. When Tn ₊₃ , the average value of M _{3 to} Mn ₊₂ is calculated. In this way, the sample value is updated and the average power is calculated momentarily. It is possible to obtain an average power value considering the demand characteristic of T × K time.

Fig. 4 shows the relationship between the detected power value and the average power value at the end of the demand time T of the transaction demand power meter. If each of the transaction demand power meter lasts T ₁ and T ₂ , when placed in a demand time T for each intended to △ T time T _n from things, that each of the final value WA _1, the line connecting the WA ₂ ~WA _n are relatively consistent with the average power value WA Is shown.

That is, if the average power value according to the present invention is monitored and controlled so as not to exceed the contracted power value, it is impossible for the trading maximum demand power meter to indicate that it exceeds the contracted power. As described above, according to the present invention, the start time of the demand time of the maximum demand power meter for transaction and the start time of the demand time of the maximum demand power monitoring and control device do not always match, that is, they do not have to be synchronized. Become.

As described above, according to the present invention, the average electric power from the time before the present time to the present time by T × K is momentarily detected with respect to the instantaneous electric power at the present time and the demand time T of the maximum demand electricity meter for transaction, and the contract electric power is obtained. The load is limited under the condition that the detected average electric power reaches a predetermined value and the current instantaneous electric power exceeds the set predetermined value for a predetermined time or more.

Also, the demand time of the maximum demand power monitoring control device is T × K with respect to the demand time T of the demand power meter for transactions, but this is optimum in the range of 0 <K1 according to the characteristics of the load of the customer. The value is selected. That is, if the instantaneous power is WI, the time to reach WI in the demand time T ₁ is T ₁ , and if it is T ₂ , if this value is larger than the demand time T of the transaction demand power meter, the detection is the demand power for transaction. It will be later than the total detection.

When it is smaller than T, it can be detected quickly. However, if it is too small, the advantage of the demand characteristic will be reduced. Therefore, if the optimum value is determined by changing the selection of the demand time for the load characteristic of the customer, for example, the load that changes abruptly and the load that changes little. Good.

In the above embodiment, an analog amount is detected by the power converter and converted into a digital amount. However, instead of the power converter, a watt hour meter is used, and the pulse amount from this pulse oscillator is changed every moment. You may obtain | require an average electric power value from a value.

〔The invention's effect〕

Since the contract power value is a contract between the power supply company and the customer that the average power value within the demand time T is not exceeded, the average power (demand time T × K, where K is a proportional constant 0).
If <K ≦ 1) is less than or equal to the contract power value, it means that the value is less than or equal to the contract power value. While the maximum demand power meter detects and records the average power within T time once every T time, the average power is continuously detected every moment, so continuous monitoring is possible. Further, if the instantaneous power value is added, more accurate monitoring can be performed.

As described above, according to the present invention, the maximum demand power can be monitored simply by obtaining the average power every moment and comparing this value with the contract power, so that the maximum demand power monitoring becomes easy and does not need to rely on an expert. In addition, highly accurate monitoring is possible. Since it is not necessary to synchronize with the maximum demand electricity meter for transactions, unmanned and labor-saving is possible. Furthermore, in order to cover the disagreement of the start time of the maximum demand electricity meter for transaction and the maximum demand electricity meter,
In some cases, there was a margin in the contracted power, but there was an effect such as being economical because it could be reduced.

[Brief description of drawings]

1 to 4 are diagrams for explaining one embodiment of the maximum demand power monitoring control device according to the present invention. FIG. 1 is a block diagram, and FIG. 2 is an average value detected as a load change. For explaining the relationship between the change in the power consumption and the contract power, FIG. 3 is a view showing the process of calculating the average power, and FIG. 4 is a view showing the relationship between the average power and the detected value of the demand power. 1PT, 2CT, 3 power converter, 4 instantaneous power detector, 5 A / D converter, 6 memory circuit, 7 timer, 8 contract power setting unit, 9 arithmetic unit, 10 logic unit, 11 load, T ... demand time , K ... constant

Claims (1)

[Claims] 1. The demand time limit of the instantaneous power detection unit and the maximum demand electricity meter for transaction installed by the power supply company is set to T, and T × K (K is a proportional constant 0 <K ≦ 1) is the current time. Detection of dividing the amount of power used up to a later time by T × K to obtain an average power value at the current time, and detecting the above average power value every moment when a plurality of equal times of T × K time elapses. And a power value (hereinafter referred to as a contract power value) obtained by dividing the maximum demand power amount contracted with the power supply company by the demand time period T, and a setting unit having a power value less than the contract power value as a set value. And a determination unit that determines that the average power value is less than the contract power value and has reached the range of the set value or more, and the average power value is within the range and the instantaneous power value exceeds the contract power value. The instantaneous power value is contracted under the condition that Maximum demand power monitoring control apparatus characterized by comprising a logic unit consisting of an output section for outputting a signal for the load shedding is proportional to the power value of the excess in excess than the force value demand side.