JPS6052649B2 - Production load monitoring control method for demand control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a production load monitoring and control method for a demand control system that monitors a production load in accordance with a signal output from a demand control device and controls the production load continuously or stepwise.

The demand control device is designed to prevent the power consumption during the demand period from exceeding the contracted maximum demand power, and calculates the predicted value from the current value of the power consumption, the sampling value, and the remaining time, and calculates the predicted value. If it does not match the target value, the amount of decrease or increase in load (referred to as adjustment amount) required to make the power usage match the target value at the end of the demand time period is calculated. Conventionally, loads were turned on and off according to the amount of adjustment from a demand control device, but these loads can be turned on and off using environmental equipment,
For example, cooling equipment, compressors, lighting, etc., and it is impossible to turn on and off production loads such as electric furnaces, valves for controlling the flow rate of steam, motors, rectifiers using thyristors, etc. because it affects the product during the process. It was hot. Therefore, conventionally, the production load has been controlled manually and continuously at best, and there has been no automatic control using the output of a demand control device. The load that can be turned on and off has a load capacity of, for example, 7KW, 15KW,
Since it is fixed at 20KW or 38KW or 50KW as a block, if the adjustment amount from the demand control device is, for example, 65KW, there is almost no load capacity that matches the adjustment amount. In case of decrease, the nearest value beyond the adjustment amount, e.g. 10
0KW is stopped, and in the case of an increase, the closest value below the adjustment amount, for example 50KW, is input. Due to such load failures, interruptions, and insufficient inputs, it becomes difficult for the power consumption to match the target value at the end of the demand time period. On the other hand, a demand control system has already been proposed in which the production load of an adjustable type such as an arc furnace is automatically controlled.

However, this method involves the following problems because the load control effect is determined by pulses from a power meter for power trading that measures the power amount of the entire load. (a) Since only one wattmeter for power trading is connected to the main source of the consumer's power source, it is not possible to grasp the current value of each individual production load after control.

(b) The number of pulses from the electricity meter for electricity trading is, for example, 2
000P/KWH, the pulse cycle is relatively long (110V
, 0.9526 for three-phase three-wire system with a rated load of 5A.
KWH×2000P/KWH=1905P/H=31P
/min), therefore, the measurement accuracy cannot be made any more fine-grained, and it is necessary to take a certain amount of time to make detailed determinations of individual load controls, and this time is not the ratio of the load control responses; , it takes an extremely long time.

An object of the present invention is to solve the above-mentioned problems and provide a production load monitoring and control method for a demand control system that can quickly and precisely monitor and control the production load in response to signals from a demand control device. There is something to offer.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a demand control system according to the present invention, in which the loads L1 to Ln to be controlled are
4, among which loads L1 to L3,... are loads that can be turned on and off,
The loads Ln-, , Ln are production loads that cannot be turned on or off.

Electric power is supplied to each load Ln through a transaction transformer 1, a voltage transformer 2, a transformer TRl, a disconnector CBl-CBn, and a transformer TRl-7. The amount of power used by the loads L1 to Ln is measured by a power meter 3 with a transmitter. The watt-hour meter 3 with a transmitting device emits a pulse with a frequency proportional to the electric power, and while this pulse is sent to the demand wattmeter 4, it is detected by a pulse detector 5, and amplified and shaped by a pulse converter 6. and input it to the demand control device 7. The demand control device 7 measures the current value by integrating the input pulses, and also measures the current value within a sampling time (for example, 1 minute). Measures the sampling value from the number of pulses, calculates the predicted value at the end of the demand period from the current value, sampling value, and remaining time of the demand period (for example, 3 pulses), and then sets the power consumption at the end of the demand period to the target value. Calculate the amount of load adjustment required to match. The current value is also compared with a limit value that is set slightly smaller than the contract power. The demand control device 7 outputs a decrease command signal or an increase command signal together with an adjustment amount signal when the load needs to be decreased or increased. Furthermore, when the current value becomes equal to the limit value, a limit command signal is output. It also constantly outputs the remaining time signal. The demand control signal from the demand control device 7 is
Input to transmitter 8. The transmitter 8 includes an on/off receiver RVl provided for each load level L3, . . . that can be turned on/off.
~RV3,... is the production load L. ．． The load monitoring control device 9 is configured together with the analog receivers RVn-1 and RVn provided for each of -1 and Ln. The receivers RVl-RVn are connected to the transmitter 8 by two common transmission lines. Analog receivers RVn-1, RVn are controllers RG, -1, RG
, etc. to control the production loads Ln-1 and Ln. FIG. 2 shows the configuration of the transmitter 8. t1 is a terminal to which a demand control signal from the demand control device 7 is input; T2 is an on/off receiver RVl to R3, . . . and an analog receiver RV. -1, RV. This is a terminal for inputting and outputting signals to and from these terminals. The numeric key switch section 10 has a numeric keypad 11 for 0 to 9, and an all clear key 12.
and an increment key 13. The command switch unit 14 includes a load capacity key K1, a control method key K2, a control order key K3, a write key K4, a monitoring key K5, a simultaneous off key 11 individual off key K7, an individual on key, and a start key. The operation of the transmitter 8 will be explained.

a. Before performing initial setting automatic control, set the conditions for the loads L1 to Ln.

First, the automatic/manual changeover switch 15 is switched to manual, and the receiver address number 1 is selected using the numeric keypad 11. At this time, 1 is displayed on the receiver address display 17 of the display section 16. On/off receiver, receivers RVl to RV3,... are 1
Assigned to the address from the street address, the analog receiver R
Vn-1 and RVn are assigned to subsequent addresses. The load capacity of the load connected to the on/off receiver RVl at address 1 is displayed on the load capacity display 18 by pressing the load capacity key K1 and the numeric keypad 11, and then by pressing the write key K. memory for setting conditions 19゛1
Memorize the address.

Similarly, whether the control method for the load L is a priority method or a cyclic method, and the control order are displayed on the control method display 20 and the control order display 21 using the control method key K2, the control order key K3, and the numeric keypad 11. It is also stored in the setting condition memory 9. The priority control method means that the control method is cut off from the top of the order, and the control is started from the bottom of the order. It is set at ゜゜0゛ and ``゜1゛.The control order of the production loads Ln-1, Ln is determined from the control order of the loads L1 to L, which can be turned on and off. Similarly, the load capacity, control method, and control order are sequentially set for the on/off receivers RV2, .

Analog receiver RVn-1 of production load Ln-19Ln,
Regarding RVn, an operation target value is set in addition to the load capacity, control method, and control order. The operation target value is set on a daily basis depending on the production situation. To set the driving target value, press the individual ON key ENTER and set the driving target value by pressing 1 on the numeric keypad.
1 to display it on the operation target value display 22, and press the write key K4 to store it in the setting condition memory 19. With the automatic/manual changeover switch 15 set to manual, display the receiver address on the receiver address display 17 using the numeric keypad 11, and press the monitor key ENTER to sequentially call up the receivers RVl to RVn for each address. Regarding the on/off receivers RV1 to RV3,..., the on/off status, whether there is an abnormality or not, and whether the load is in a state of refusing automatic control is displayed on the receiver status display 23, and stored in the setting condition memory 19. be remembered.

For analog receivers RVn-1 and RVn, current values are displayed on the current value display 24 instead of on/off states and are stored in the setting condition memory 19. Also, when switching from manual to automatic, all receiver RVl
-RVn are automatically monitored and stored in the setting condition memory 19 according to the control order. The simultaneous off key K6, the individual off key K7, and the individual on key K8 are operated when manually sending a command signal to the on/off receivers RV1 to RV3, . . . , and when the start key K9 is pressed, a signal command is transmitted. The battery 25 is used to retain the contents of the setting condition memory 19 even in the event of a power outage. When the b reduction command signal is input, the automatic/manual changeover switch 15 is switched to automatic when automatic control is to be performed by the signal from the demand control device 7.

When a reduction command signal and an adjustment amount signal are input from the demand control device 7, the demand control signal receiving section 26 sends these signals to the arithmetic processing section 28 via the interface 27, and the arithmetic processing section 28 discriminates these signals. . First, it is checked whether or not the control was performed within one minute, and if the control was performed within one minute, nothing is done.
If no control is being performed, a monitoring command signal is sent from the signal transmitting/receiving unit 30 to all the receivers RVl to RVn via the interface 29, and the latest receiver status (on/off status, abnormality or not, automatic control The current 7 values of the production load (whether it is in a rejected state or not) are returned from the receivers R1 to RVn,
It is stored in the setting condition memory 19. The stored contents of the setting condition memory 19 of the on-off receiver having a higher control order are read out to confirm that the on-off receiver is normal, can be automatically controlled, and is turned on.

If any one of these conditions is not met, that on-off receiver is skipped and the process moves to the next on-off receiver in the control order. After confirmation, the arithmetic processing unit 28 calculates by subtracting the load capacity of the on/off receiver from the adjustment amount, and if there is a surplus of adjustment amount, subtracts the load capacity of the next on/off receiver.In this way, the amount of adjustment is adjusted. On/off receivers for each load capacity are determined, and a shedding command signal is sequentially transmitted to these on/off receivers. If the amount of adjustment is insufficient with only the on-off receivers, or if a reduction command signal is further input when all the on-off receivers are already in the off state, the calculation is performed for the analog receivers RVn-1 and RVn.

This calculation will be explained with reference to the flowchart in FIG. The example shown in FIG. 3 is a case where a reduction command signal is further input from the demand control device 7 when all the on-off receivers are already in the off state. The adjustment amount is subtracted from the current value obtained by monitoring, and if the remainder is greater than 0, the adjustment amount is sent as a reduction control amount to the analog receiver together with a reduction command signal, and if the remainder is less than 0,
Send the current value as a decrease control amount. If the adjustment amount is too large and the number of controllable receivers is insufficient, a shrunken command signal or a reduction command signal and a reduction control amount signal are sequentially transmitted to the controllable receivers, and an alarm is issued via the interface 31. The display circuit 32 is operated to issue an alarm to notify that the adjustment amount could not be fully controlled, and the printer 34 is operated via the interface 33 to print out.

One minute after controlling, all receivers RVl to RVn
The state of the receiver is stored in the setting condition memory 19 and reprinted by the printer 34.

The operation of the arithmetic processing unit 28 described above is performed according to the program stored in the program memory 35, and storage during the calculation is performed by the arithmetic memory 36. Interfaces 37 and 38 are provided between the arithmetic processing section 28 and the display section 16, numeric keypad switch section 10, and the like.
c When an increase command signal is input Similar to when a decrease command signal is input, the status of all receivers RVl to RVn is first monitored and stored in the setting condition memory 19. Then, those that are in a state where automatic control is possible and whose Z current value is smaller than the driving target value are selected from those lower in the control order, and the increased control amount is calculated.

A flowchart of this calculation is shown in FIG. When the difference A between the operation target value and the current value is smaller than the adjustment amount, the difference A becomes the increased control amount, and when the difference A is equal to or larger than the adjustment amount, the adjustment amount becomes the increased control amount and an increase command is issued. The signal is transmitted together with the control amount signal to an analog receiver. next,
Select on-off receivers that are normal, can be automatically controlled, and are off according to the control order, determine on-off receivers with load capacities commensurate with the amount of adjustment, and sequentially apply to these on-off receivers. Sends a closing command signal.
(f) If the adjustment amount is too large and there are not enough controllable receivers, sequentially transmit an increase command signal and an increase control amount signal or input command signal to the controllable receivers and print them out.

One minute after the control is performed, all receivers are monitored, their statuses are stored in the setting condition memory 19, and printed out. d When a limit command signal is input When a limit command signal is input from the demand control device 7, it transmits a simultaneous off command signal that turns off only the on/off receivers RV1 to RV3, and so on. Print out.

It is the same to monitor, store and print out after 1 minute.

FIG. 5 shows a block diagram of the on-off receiver.

The terminal T3 is a terminal connected to the transmission line from the transmitter 8, and ζ is a terminal connected to the loads L1 to I-3, . . . which can be turned on and off. The signal from the transmitter 8 is received by the transmitting/receiving section 39 and sent to the arithmetic processing section 41 via the interface 40.
The paging command signal and other signals are determined by When a monitoring command signal is received, the on/off state detected from the state of the load control power relay 42 and the state of the automatic control rejection selection switch 43 are transmitted to the interfaces 44 and 45.
The arithmetic processing unit 41 detects the signal and transmits it to the transmitter 8.
The automatic control rejection selection switch 43 is operated when automatic control is not desired. When receiving a shedding command signal or a closing command signal, the arithmetic processing unit 41 determines the command signal and turns off and on the load control power relay 42. This state is displayed by the load state display section 46. The arithmetic processing program of the arithmetic processing section 41 is stored in a program memory 47. The calculation memory 48 is used for calculations such as signal discrimination. FIG. 6 shows a block diagram of an analog receiver. Terminals are terminals connected to the transmission line from transmitter 8, terminals! is a terminal that outputs an absolute quantity signal to a controller, etc., and a terminal that inputs the current value from a controller, etc. is a terminal to which a signal indicating the state of the production load or the automatic control rejection selection switch provided in the controller is input. Transmitter 8 by transmitter/receiver 49
A signal is received from the computer, and the content of the signal is determined by the arithmetic processing unit 51 via the interface 50. When the arithmetic processing unit 51 determines the monitoring command signal, it inputs the current value from the terminal, which is converted into a digital signal by the A/D converter 52, and the terminal! , and transmits to the transmitter 8 a signal indicating whether or not the automatic control rejection state detected by the automatic control rejection detection unit 53 is present. When a decrease command signal or an increase command signal and a controlled amount signal are received, the controlled amount is converted to an absolute amount, and this absolute amount signal is converted to an analog signal by the D/A converter 54 and sent to a controller, etc. Sent.
55 and 56 are program memories and calculation memories.

In order to explain the operation of the arithmetic processing section 51 in detail, FIG. 7 shows a block diagram when the software of the arithmetic processing section 51 is replaced with hardware.

When the paging command discriminating circuit 57 determines a paging command signal that matches the assigned receiver address, the lower flip-flop F1 is set, and the set output causes the increase command discriminating circuit 58, the decreasing command discriminating circuit 59, and the monitoring command discriminating circuit. 60 becomes operational. When a monitoring command signal is input, the monitoring command determination circuit 60 determines this and opens the AND gates Gl and G2. Therefore, the pure binary digital signal indicating the current value of the A/D converter 52 is transmitted to the KW conversion circuit 61.
The signal is converted into a binary w-ary system signal, and transmitted from the signal transmitting circuit 49b to the transmitter 8 via an AND gate G1 and an OR gate G3. Further, a signal indicating whether or not the automatic control rejection detection unit 53 is in the automatic control rejection state is transmitted from the signal transmission circuit 49b via the AND gate G2 and the OR gate G3. When the increase command signal and the increase control amount signal are input, the increase command discrimination circuit 58 discriminates them and sets the flip-flop FF2, and the set output opens the AND gate G4 and is sent to the up input terminal U of the up/down counter 62. to set the addition mode. The count value of the up/down counter 62 indicates the absolute amount of production load. The increased control amount signal is sent to the KW conversion circuit 63.
is converted from binary coded decimal system to pure binary system and inputted to comparison circuit 64. By opening the AND gate G4, the clock pulse from the clock pulse generation circuit 65 is input to the up/down counter 62 and the control counter 66 via the AND gate G4 and the OR gate G5. K.W.
When the increased control amount output from the conversion circuit 63 and the count value of the control counter 66 match, the comparison circuit 64 resets the flip-flop FF2 and closes the AND gate G4. Therefore, the clock pulse up/down counter 6
2 and the control counter 66 are cut off, and the counted value of the up/down counter 62, that is, the absolute amount of production load becomes the current value plus the increased control amount. Control counter 66 is reset by the output of comparison circuit 64. The absolute amount that is the output of the up/down counter 62 is the output of the D/A converter 5.
4 is converted to an analog quantity by terminal! is output to the controller as an absolute quantity signal. When the decrease command signal and the decrease control amount signal are input, the flip-flop FF3 is set to open the AND gate G6, and the up/down counter 62 counts the current value minus the decrease control amount, and this counted value is output as an absolute amount signal. Ru.

The controller controls the production loads Ln-1 and Ln using the absolute quantity signal outputted from the terminal T6. When the termination command signal is input, the termination command determination circuit 67 selects the lower flip-flop F1.
, and disables the operations of the increase command discrimination circuit 58, the decrease command discrimination circuit 59, and the monitoring command discrimination circuit 60.

In FIG. 7, a calling command determining circuit 57, an end command determining circuit 67, an increasing command determining circuit 58, a decreasing command determining circuit 59, a monitoring command determining circuit 60, and a flip-flop lower F
1 forms a command discrimination circuit 68. In the illustrated embodiment, the transmitter 8 and the receivers RVl to RVn are separate bodies,
Although the transmission lines are connected, the loads L1 to L. are concentrated in the immediate vicinity, transmitter 8 and receivers RVl to R
It can be integrated with Vn. In addition, there are no loads L1 to L3, . . . that can be turned on and off, and the production load Ln-1
, Ln only, the present invention can be applied. Furthermore, the display section 16 of the transmitter 8 is provided with a control amount display section to display the control amount transmitted to the analog receiver.
It is also possible to store it in the setting condition memory 19, calculate the actual control amount from the current value obtained by monitoring one minute later, and compare it with the transmitted control amount. As explained above, according to the present invention, each time a decrease command signal or an increase command signal and an adjustment amount signal are input from the demand control device, the current value for each production load is monitored, and the current value and adjustment amount are Calculate the controlled amount to be decreased or increased for each production load from and convert the controlled amount into the absolute amount of the production load,
The production load is controlled by outputting an absolute quantity signal to the production load, and after a predetermined period of time, the current value of each production load is monitored, so the controlled results are reflected in the individual production loads. information can be obtained quickly, and rapid and detailed monitoring and control becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an example of a demand control system according to the present invention, FIG. 2 is a block diagram of a transmitter according to an embodiment of the present invention, and FIG. 3 is a block diagram of a transmitter according to an embodiment of the present invention. Flowchart explaining reduction control amount calculation, 4th
The figure also shows a flowchart explaining the increased control amount calculation.
FIG. 5 is a block diagram of an on-off receiver according to an embodiment of the present invention, and FIG. 6 is a block diagram of an analog receiver.
FIG. 7 is a block diagram of an analog receiver according to an embodiment of the present invention in which software is replaced with hardware. 7...Demand control device, 8...
...Transmitter, 9...Load monitoring control device, RVn
-1, RVn...Analog receiver, Ln-1, Ln・
...Production load.

Claims (1)

[Claims] 1 Every time a decrease command signal or an increase command signal and an adjustment amount signal are input from the demand control device, the current value for each production load is monitored, and the control amount to be decreased or increased is produced based on the current value and the adjustment amount. The control amount is calculated for each load, the control amount is converted to the absolute amount of the production load, and the absolute amount signal is output to the production load to control the production load. A production load monitoring control method for a demand control system that monitors the current value.