JPH04317520A - Controller for selective load interruption - Google Patents

Abstract

PURPOSE:To realize a system for supply power to a plurality of loads wherein the loads are interrupted sequentially in reverse order of importance and the important load is interrupted finally upon occurrence of abnormality in a power system under any operating conditions. CONSTITUTION:Priority of interruption of respective loads are stored for each type of operating condition while estimating the lowering of power supply amount. Upon lowering of the power supply amount, priority of interruption corresponding to current operating conditions is detected and the loads are interrupted sequentially until a required amount of load is interrupted.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a power supply system that supplies power from a power system to multiple loads, and in particular, the present invention relates to a power supply system that supplies power from a power system to multiple loads, and in particular, when a failure of some kind occurs in the power system and the amount of power supplied decreases, the present invention relates to a power supply system that supplies power to multiple loads from a power system. The present invention relates to a load selection and cutoff control device that automatically selects a load to be cut off.

0002

2. Description of the Related Art A large scale plant such as a factory is equipped with a large number of equipment. And many facilities are powered by electricity. Therefore, a large number of loads such as motors, electric heaters, and measuring devices that drive each of these facilities are supplied with electric power from the power system according to the load amount of each load. The power system that supplies power to such a large number of loads includes a plurality of private power generation devices using, for example, oil, in addition to the commercial power supplied by the power company.

In this way, by setting up multiple power supply sources, even if the commercial power supply is cut off due to a power outage, for example, the remaining private power generators can continue to provide power to important loads. We are able to supply it. The same applies when other private power generators fail.

[0004] Therefore, in such a case, the amount of power supplied to the power system decreases, so the power supply to less important loads is cut off to prevent the voltage drop in the power supply to important loads and to restart operation. We need to be able to continue normally.

[0005] Conventionally, when the amount of power supplied from an electric power system decreases, which loads are to be cut off and which loads are to be left in place are ranked in advance in accordance with the importance of each load. Then, when the amount of power supply decreases, the total load amount of each load currently in operation is determined, and the difference between this total load amount and the amount of power supply after the decrease is set as the required amount of power to be shut off. and,
Select the loads in order starting from the highest priority, and at the same time,
The load amount of the selected load is added up, and when the total load amount reaches the above-mentioned cutoff required power amount, the selection is stopped. Then, the power supply to each load selected at that time was cut off using a hardware circuit of an external preset board.

[0006]

However, even with the load selection and shedding control device which selects the load to be shelved in accordance with the procedure described above, there still exist the following problems.

[0007] In general, large-scale plants such as factories are equipped with a large number of equipment as described above, but not all equipment is operated under the same conditions.
It varies depending on the type of product being manufactured and the manufacturing process. Therefore, the most important equipment changes from time to time. Therefore, when the amount of supplied power decreases due to a power outage or failure, it is necessary to leave the most important load on the equipment at the time of the decrease and shut off other unimportant loads.

However, in the above-mentioned apparatus, each load to be cut off is selected according to one type of cut-off order set in advance. As a result, depending on the timing of an abnormality such as a power outage or failure, the loads at the top of the cutoff order are important equipment, and power to these important loads is cut off preferentially, while less important loads are cut off. There was an inconvenience that the system continued to operate without being shut off.

The present invention has been made in view of the above circumstances, and it stores the cutoff priority of each load for each type of operating condition, and when the power supply decreases, the cutoff priority corresponding to the current operating condition is stored. By detecting the It is an object of the present invention to provide a load selection shedding control device that can improve reliability.

0010

[Means for Solving the Problems] In order to solve the above problems, the present invention aims to prevent abnormalities from occurring in a power supply system that distributes power supplied from a power system to a plurality of loads in accordance with each load amount. In a load selection cutoff control device that cuts off power supply to a load selected from a plurality of loads when the power supply amount of the power system decreases due to

[0011] A priority cutoff pattern memory that stores the cutoff priority of each load when the amount of power supply decreases for each type of operation status of a plurality of loads, and an operation status that detects the current operation status in response to a decrease in the amount of power supply. A detection means, a required power amount calculation means for calculating a required power amount to be cut off in response to a decrease in power supply amount, and a power cutoff priority order for each load in a type corresponding to the operating condition detected by the operating condition detection means. A cutoff priority search means searches from the priority cutoff pattern memory, and each load is sorted in order of the highest priority loads detected by this cutoff priority search means, and the total value of the loads of the selected loads is the required power consumption for cutoff. The cutoff load selection means selects the cutoff load until the cutoff load is reached.

0012

[Operation] With the load selection shedding control device configured in this way, the priority shedding pattern memory stores information in which each load is being operated in the pattern of this operation type for each type of operation status of each load. The shutdown priority of each load is stored when it is assumed that the power has decreased.

[0013] When an abnormality such as a power outage or failure occurs in the power system and the amount of power supplied decreases, the operating status of each load at the current time is detected. Further, the amount of power required to be shut off in this operating situation is calculated. Furthermore, a shutoff priority order corresponding to the type of current driving situation is read from the priority shutoff pattern memory.

[0014]Then, the loads are sequentially selected in order of priority until the amount of power required to be cut off is reached. Power is cut off to each selected load. Therefore, the probability that the power supply to important loads will be cut off at that point is low.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram showing the entire power supply system to which the load selection shedding control device of the embodiment is applied. The power system 1 houses one power receiving panel 3 to which power is supplied from an external commercial power source 2 and two private generators 4a and 4b. Then, from the power system 1, each switch 5
a, 5b, 5c, 5d, 5e, and transformers 6a, 6b
, 6c, 6d to form the plant 8.
Necessary power is supplied to each load 7 on the stand.

FIG. 3 is a block diagram showing a schematic configuration of the load selection shedding control device. In the figure, reference numeral 9 denotes a control section made of, for example, a microcomputer, and this control section 9 includes an auxiliary storage device 10 made of, for example, a magnetic storage device that stores a priority cutoff pattern memory, a key input device 11a such as a keyboard operated by an operator, and An input/output terminal device 11 consisting of a screen display device 11b such as a CRT display, a process signal input device 12 to which various process signals including the operating status signal a of each load 7 are input from the plant 8, and a selected power source to be cut off. A process signal output device 14 and the like for applying a selection signal b of each load to the load selection cutoff preset board 13 is connected.

[0018] Note that the operating status signal a is
It includes information on whether each load 7 constituting the is currently operating or stopped, and if it is operating, at what percentage of the rating it is operating, that is, the amount of load (power consumption) during operation.

[0019] Furthermore, a system failure signal c is transmitted from the power system 1.
is input. This system failure detection signal c indicates that a failure has occurred in the power system 1, resulting in a decrease in the amount of power supplied, a failure (power outage) in the power receiving board 3 in the power system 1, or a failure in either of the private generators 4a and 4b. It also includes information.

The load selection cutoff preset board 13 is composed of a unit switch for each load inserted between the power system 1 and each load 7 of the plant 8, and a bypass switch that commonly bypasses each unit switch. has been done. Each unit switch is controlled to open and close by a load selection signal b output from the control section 9 via the process signal output device 14. On the other hand, the bypass switch is normally in a closed state, and when the system failure signal c is input from the power system 1, it is opened.

That is, when the power system 1 is in a normal state,
Since the bypass switch is closed, power is unconditionally supplied from the power system 1 to each load 7. When the system failure signal c is input from the power system 1, the bypass switch is opened, so that power is supplied from the power system 1 only to the load 7 whose unit switch is closed.

FIG. 4 is a diagram showing the priority cutoff pattern memory 15 stored in the auxiliary storage device 10. In the plant 8 shown in FIG. 2, four types of operating conditions No. 1 to No. 4 are set. For example, the operating status No. 1 (P = 1) indicates that the total load of load A and load B is smaller than the amount of power received by the power receiving board 3, and the operating status No. 2 (P = 2) indicates that the total load amount of load A and load B is smaller than the amount of power received by the power receiving panel 3. This indicates that the total load amount of load B is larger than the amount of electric power received by the power receiving board 3, and the load amount of load E is less than 700 KW.

[0023] The cut-off priority order of each load 7 is set for each operating condition from No. 1 to No. 4. For example, in the operating situation No. 1 mentioned above, load A is set to No. 1 (C = 1), load B is set to No. 2 (C = 2), and the following 3,
Loads C, D, and E are set to numbers 4 and 5, respectively. That is, if an abnormality occurs in the power system 1 and the power supply decreases while the plant 8 is operating in the first operating condition, the load A will be selected as the load to be cut off first. show.

FIG. 1 is a diagram showing each configuration created by software using a control program in the control section 9 formed by the microcomputer. Process signals including the operating status signal a inputted via the process signal input device 12 are inputted to the required cut-off power amount calculating means 9a and the operating status detecting means 9b. In addition, a system failure signal c input from the power system 1 is also input to the required shutoff power amount calculation means 9a and the operating status detection means 9b.

When the system failure signal c is input, the required power for interruption calculation means 9a calculates the required power for interruption Wa and sends it to the interruption load selection means 9d. In addition, the driving status detection means 9
When the system failure signal c is input, the system b detects the current operating status of each load 7 of the plant 8 and sends it to the next shutoff priority search means 9c. The cutoff priority order search means 9c searches the priority cutoff pattern memory 15 using the input operating condition, reads out the cutoff priority order of the corresponding operating condition, and sends it to the cutoff load selection means 9d. The cutoff load selection means 9d selects the load 7 to be cut off based on the required cutoff power amount Wa and the cutoff priority, and sends the selection signal b to the process signal output device 14.
Send to.

[0026] The pattern memory setting means 9e is configured by the operator to operate the key input device 11a to set the auxiliary storage device 10.
The settings of the priority line interruption pattern memory 15 shown in FIG. Access processing for the auxiliary storage device 10 is executed in response to various operation instructions when creating the memory 15. FIG. 5 is a flowchart showing detailed operations of each means 9a to 9d in FIG. 1 when a failure occurs.

When the system failure signal c is input from the power system 1, the operating status signal a included in the process signal input from the process signal input device 12 is read in Q1. In Q2, the total load amount of each load 7 currently in operation included in the operating status signal a is calculated. Furthermore, the faulty power receiving board 3 or each private generator 4 is read from the system failure signal c from the total power supply amount in the power system 1 during normal operation known in advance.
Find the current power supply amount by subtracting the power supply amounts of a and 4b. Then, the required shutoff power amount Wa is calculated by subtracting the reduced power supply amount from the total load amount.

In Q3, the current operating status of each load 7 is checked from the operating status signal a. Auxiliary storage device 1 in Q4
The type number P in the priority cutoff pattern memory 15 of 0 is set to an initial value of 1. In Q5, the operating condition specified by the type number P in the priority cutoff pattern memory 15 is read. In Q6, it is checked whether the driving situation previously obtained from the driving situation signal a matches the driving situation specified by the current type number P. If they do not match, 1 is added to the type number P in Q7, and the process returns to Q5 to read the driving situation specified by the type number P after the addition.

[0029] In Q6, if both driving conditions match,
Since the type number P of the operating status of each load 7 of the plant 8 at the current point in time has been determined, proceed to Q8 and initialize the cutoff priority order C corresponding to the corresponding type number P in the priority cutoff pattern memory 15 to 0 ( C=0). Furthermore, in Q9, the breaking load amount W is initialized to 0 (W=0). When the above initial setting process is completed, in Q10, the cutoff priority C
Add 1 to (C=C+1). Next, in Q11, the load amount Wc at the current point in time (at the time of abnormality occurrence) of the corresponding cutoff priority order C is read from the above-mentioned operating status signal a and added to the cutoff load amount W (W=W+Wc). When it is confirmed in Q12 that the cutoff load amount W after the addition is not greater than the previously determined cutoff required power amount Wa, the process returns to Q10 and 1 is added to the cutoff priority order C.

However, in Q12, when the cutoff load amount W after addition becomes equal to or greater than the above-mentioned cutoff required power amount Wa, there is no need to cut off any new load 7, so in Q13, the order is changed from rank 1 to Loads 7 belonging to each of the respective cutoff priorities up to C are selected, and a selection signal b specifying each of the selected C loads 7 is sent to the load selection cutoff preset board 13 via the process signal output device 14. As a result, the power supply to each selected load 7 is cut off.

In the load selection shedding control device configured as described above, when the power system 1 is normally supplying power, each load 7 of the plant 8 is assigned a load according to the operating situation at the time. The necessary power is supplied corresponding to the current load amount of 7.

[0032] When the power supply amount of the power system 1 decreases due to a power outage accident or failure, etc., the load selection shedding control device is informed of the system information including information on which device in the power system 1 is unable to supply power. A fault signal c is sent out. The load selection shedding control device that has received the system failure signal c calculates the necessary information to operate the plant 8 based on the operating status of each load 7 included in the operating status signal a among the plant signals input from the plant 8. The required shutoff power amount Wa is calculated. Then, the loads 7 to be cut off are selected in order based on the cutoff priority order set in advance in the priority cutoff pattern memory 15 for the corresponding operating situation, until the cutoff load amount W reaches the required cutoff power amount Wa. be done. Each selected load 7 is disconnected from the power system 1 by the load selection cutoff preset board 13.

[0033] In this way, when some kind of abnormality occurs in the power system 1 and the amount of power supplied decreases, the loads to be cut off are selected in order from the least important loads 7 in the operating status of each load at that time. The most important load 7 is finally selected as the breaking load.

[0034] Therefore, no matter what operating situation the power supply decreases, the probability that the most important load at that time will be cut off is greatly reduced. As a result, losses in plant operation due to a decrease in power supply can be minimized, and the reliability of the entire power supply system can be improved.

[0035]

Effects of the Invention As explained above, according to the load selection shedding control device of the present invention, it is possible to store the shedding priority of each load when the amount of power supply decreases for each type of operating situation, and to The load to be cut off is selected by detecting the cut-off priority order corresponding to the operating status of the load. Therefore, even if an abnormality occurs in the power system during any operating situation, the loads to be cut off are always selected in order starting from the unimportant loads at that time, and the important loads are selected last, thereby increasing the reliability of the entire power supply system. can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a load selection shedding control device according to an embodiment of the present invention;

[Figure 2]
A schematic diagram showing the entire power supply system to which the device of the embodiment is applied,

[Figure 3] A block diagram showing the overall configuration of the device of the embodiment,

FIG. 4 is a diagram showing a priority cutoff pattern memory formed in the auxiliary storage device of the same embodiment device;

FIG. 5 is a flowchart showing the operation of the device of the embodiment.

[Explanation of symbols]

1...Power system, 7...Load, 8...Plant, 9...Control unit,
DESCRIPTION OF SYMBOLS 10...Auxiliary storage device, 11...I/O terminal device, 12...Process signal input device, 13...Load selection cutoff preset panel, 14...Process signal output device, 15...Priority cutoff pattern memory, a...Operating status signal, b... Selection signal, c...system failure signal.

Claims (1)

[Claims] 1. In a power supply system that distributes power supplied from a power system to a plurality of loads in accordance with each load amount, when the power supply amount of the power system decreases due to an abnormality occurrence, In the load selection and cutoff control device that cuts off power supply to a load selected from the plurality of loads, a cutoff priority order of each load is stored when the power supply decreases for each type of operating status of the plurality of loads. a priority cutoff pattern memory; an operating status detection means for detecting the current operating status in response to the decrease in the amount of power supply;
A required shutoff power amount calculation means for calculating a required shutoff power amount in response to the decrease in the power supply amount, and a shutoff priority order of each load in the type corresponding to the operating condition detected by the operating condition detecting means. A cutoff priority search means searches from a cutoff pattern memory, and each load is selected in the order of the loads detected by the cutoff priority order search means, and the total value of the loads of the selected loads is determined as the required cutoff power amount. A load selection shedding control device comprising a load shedding selection means that selects a load until it reaches.