JPH04138026A - Power control system for production line - Google Patents

Abstract

PURPOSE:To suppress power demand within a control target value without degrading a production efficiency by a method wherein, when the power demand tends to exceed the control target value, the production schedule of a production line is so rearranged as to have the power demand not exceeding the control target value. CONSTITUTION:An intelligent cubicle controller 25 receives a production schedule from a main controller 27 and calculates an estimated power demand. The calculated results are transmitted to the main controller 27 side in order to be available for reference at any time on the main controller 27 side. The estimated power demand P is compared with a control target value PO in the intelligent cubicle controller 25 and, if there is a tendency of PO<=P, in that state, without transfer to normal demand control, an estimated power demand changing instruction is outputted. The instruction is received on the main controller 27 side of a LAN 23 and the change of the production schedule is processed.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power control system for a production line.

(Prior Art) Conventionally, in various production lines such as sheet metal processing lines, priority is given to production, so it has not been possible to use demand controllers that cut off unnecessary loads and save electricity charges. This is because on a production line, it is necessary to operate the desired power at the desired time to produce as scheduled, and productivity must be prioritized over electricity costs.

(Problems to be Solved by the Invention) However, if a demand controller cannot be introduced into the production line, there is a problem in that the contract power rate is set due to a temporal overload, and the contract power rate becomes enormous.

Additionally, since it is not possible to introduce a demand controller to the production line, if demand control is applied only to the office lighting circuit, rapid load fluctuations on the production line will affect the lighting circuit, which will frequently cut off the lighting circuit, which will have a major impact on office work. There is a problem that occurs.

Therefore, an object of the present invention is to provide a power control method for a production line that can suppress power demand within a management target value without reducing production efficiency by coordinating power receiving and distribution equipment with the production line. shall be.

[Structure of the Invention] (Means for Solving the Problems) The present invention for solving the above problems provides a data communication terminal for power control on a power receiving and distributing facility and a load side to which power is supplied from the power receiving and distributing facility. The equipment constitutes a communication network for power control, and connects the network to the network of the production line located on the load side so as to enable data communication, and when the power demand of the power receiving and distribution equipment is about to exceed the management target value, The production schedule of the production line is reorganized by referring to a database capable of calculating the power required for various production schedules so that the power demand does not exceed the management target value.

(Function) In the production line power control method of the present invention, in the above configuration, when the power demand of the power receiving and distribution equipment is likely to exceed the management target value, it is possible to calculate the required power according to various production schedules. The production schedule of the production line is rearranged with reference to the database so that the received power does not exceed the management target value.

The production schedule can be rearranged within a range that does not cause any trouble to production by appropriately intervening the operator's judgment and by inputting in advance the range in which the production schedule can be changed.

(Example) Hereinafter, the present invention will be described in detail by giving an example in which the present invention is applied to a production line for sheet metal processing.

FIG. 2 is a block diagram showing a factory power reception and distribution system implementing the present invention.

In the figure, a cubicle (intelligent cubicle) 2 that houses the power receiving and distribution equipment 1 includes a demand controller 3 and a capacitor bank 4 of, for example, 1o bank.
is located. Further, in the cubicle 2, various detectors 5 such as various instruments and temperature sensors for detecting room temperature, and attached devices 7 such as switches 6 and ventilation devices for each distribution line are arranged. A signal input section 8 that inputs detection signals, a signal output section 9 that outputs control signals to various controllers, and these signal input/output devices 8 and 9 are equipped with data communication FF 10.
are connected to constitute a cubicle-side data communication terminal 11 as a whole.

Data communication device 10 or data communication terminal 11
may be installed inside the cubicle 2, but since it is vulnerable to thermal environments, it is recommended to provide a separate box outside the housing, store it in this box, and connect it to the cubicle 2 via a communication line. It's okay.

On the other hand, the power receiving and distribution equipment 1 outputs a demand-controlled power wiring 12 that can be cut off by the demand controller 3 and a non-controlled power wiring 13 that cannot be cut off by the demand controller 3. is the load side (line side) placed for each appropriately classified load group (single load or collective load).
Data communication terminal 14. '15, 16, 17, 18
゜One switch 2 whose opening/closing is controlled by...
0 through which the individual loads are connected. Generally, the demand control power wiring 12 is wired to a lighting line on the office side, and the non-control power wiring 13 is wired to a line where machines are arranged.

Line side data communication terminals 14, 15, 16 shown
．． 17 includes a data communication device 1o, a data processing section 21, and a device control section 22. Furthermore, the data communication terminals 18 and 19 are of a type that does not include the data processing section 21.

Generally, the data communication terminals 14, 1.5, . This is established for the management department. Furthermore, the data communication terminals 18 and 19 that do not have the data processing section 21 are installed for loads that can control opening and closing of one or more loads simultaneously or in a certain sequence in response to one command. .

Each of the data communication terminals 11, 14, 15, . . . 19 is connected to a power control communication line 24 that communicates using addresses, data, and programs, forming a data communication network. However, the data communication terminals 18 and 19 that do not have the data processing section 21 may omit the data transmission function.

Furthermore, each data communication terminal 11, 14, 15.・・・
- A management side that communicates with the cubicle 19, performs various data processing, generates various control signals, and can particularly give automatic and manual operations to the cubicle 2 via the cubicle side data communication terminal 11. A data communication terminal 25 is connected.

The management data communication terminal 25 includes a communication section 10, a data processing section 26A, and an operation section 26B. This terminal 25 is connected to the line side data communication terminal 14,
15, 16...19 can also be used in common.

FIG. 3 is an explanatory diagram showing an example of a LAN.

As shown in the figure, the LAN 23 in this example has a communication line 20,
Main controller 27 and automatic programming device 2
8, a numerical control (NC) device 29, and a plurality of data processing devices 29 are interconnected, and each data processing device 2
9, each processing machine 31 (31A, 31B, 31C) is operated according to a schedule. It is assumed that the processing machine 31A is a punch press machine, 31B is a punch/laser composite processing machine, and 31C is a laser processing machine. A database 32 is connected to each member connected to the LAN 26 as appropriate.

The LAN 2B and the above-mentioned communication line 24 are connected via appropriate communication lines and are configured to be able to exchange data with each other.

As an example of scheduled operation, the main controller 27 runs multiple programs Pi (Pi, P2゜...).
Edit the execution order and the number of repetitions for each program,
When an operation command for each schedule is output to each processing machine 3], each processing machine 31 executes the scheduled operation according to the command after turning on the start button.

Each processing machine 31 may be linked and operated on a schedule.

The program Pi used for scheduled operation is created by the automatic programming device 28.

For example, when the automatic programming device 28 inputs graphic data in which a large number of holes are drilled at various locations on a flat workpiece, NC program data for numerically controlling the punch press machine 31A to drill holes in sequence is generated. generated. Further, the punch/laser multi-tasking machine 31B is programmed to perform laser processing on a hole shape that cannot be punched.

Therefore, scheduled program data is input to each processing machine 31, and the program is sequentially executed at a set speed, thereby processing products in sequence.

However, if the power is cut off during processing, the machine will stop at that point, which is not only dangerous, but also results in the product being processed being defective. Furthermore, when the emergency stop button is pressed, the machine generally operates in a safe direction and is stopped on the spot, which often results in defective products. Furthermore, in the case of a general temporary stop, in many cases, the machining is interrupted at the end of the current machining, so it is difficult to use when it takes a long time for one machining process, such as with a laser beam machine 31C. Otherwise, processing will be suspended without producing any defective products. In addition, in the case of an NC device, in the case of a - hour stop, it is not necessary to return the servo control circuit to the origin, but in the case of an emergency stop, it is necessary to start over from the origin return operation.

In this way, cutting off the power is a must for processing machines that include an NC device, and if you want to shift the operation timing for a particular process, you must either shift the start point, change the program content, or change the time for improvement. It must depend on whether a signal is given to stop.

Improvement - The time stop signal is especially proposed in this example.
- By giving a stop command, the program can be interrupted for the next machining after completing that machining, and the machining can be continued with a return command without producing defective products. According to this improved time stop signal, there will be no defective products even in laser processing.

FIG. 4 shows an external view of the management side data communication terminal 25.

The illustrated management side data communication terminal 25 is also called an intelligent cubicle controller (ICC), and has a CRT screen 33, a group of operation switches 34, a group of LED lamps 35 indicating the control status, and function switches on the operation surface. A group 36 is provided. The CTR screen 35 displays the current status and statistical values of instruments, the operating status of the line, and the like. In addition to remotely controlling the cubicle 2, various commands can be given from the switch group 34. Various commands can be given to the function switch 36 from a menu displayed at the bottom of the screen 35. In the lamp group 35, the demand controller 3 and the capacitor bank 4
The status of the control is displayed.

FIG. 5 is a block diagram showing the detailed configuration of the intelligent cubicle controller 25.

As shown in the figure, the intelligent cubicle controller 25 includes a CPU section 37 connected to the above-mentioned communication section 6, and the CPU section 37 includes the above-mentioned CRT 33. In addition to switches 34 and 36 and a lamp 35, a printer 38, a database 39, and an external memory 40 are connected. The database 39 stores various types of knowledge for power control or power management. The memory 40 stores various data including data detected from instruments.

The CPU section 37 includes a demand control condition calculation section 41
, a capacitor switching condition calculation unit 42 , and a power prediction unit 4
3 and a power management section 44.

The power prediction unit 43 inputs detection signals from five detectors such as an ammeter, a voltmeter, a power (active/inactive) meter, and a thermometer, and also receives data input from the line side data communication terminals 14 to 17, or Refer to the program analysis results,
Fuzzy inference is given as appropriate to predict the power (valid, inactive), and as will be detailed later, when there is a possibility that the predicted power will exceed the management target value of demand power, the demand control condition calculation unit 41 performs condition calculation. It outputs control conditions to the demand controller 3, and exchanges information with other data communication terminals 14 to 19 for power reduction as appropriate.

Further, the reactive power is output to the capacitor switching condition calculating section 42, and the capacitor switching condition is calculated. As shown in FIG. 6, the power management section 44 includes each processing section 45 to 51.
It performs various power management such as recording line operating status, recording distribution load, controlling the opening and closing of distribution lines, fault diagnosis, communication with lines, controlling incidental equipment, and recording maintenance.

FIG. 7 is a block diagram showing an example of the configuration of the line side data communication terminals 14 to 17.

As shown in the figure, the line side data communication terminals 14~
17 includes a received data program analysis section 52 and a communication data/program generation section 53 connected to the above-mentioned communication section 10, a power control condition calculation section 54 connected to these analysis section 52 and generation section 53, and the above-mentioned It is configured to include a line condition setting section 55 and a switch control section 56, which correspond to the equipment control section 22.

The power control condition calculation unit 54 inputs the current and future operation schedules of each machine from the line condition input unit 57 by communicating with, for example, the main controller 27 of the LAN 23, converts this into data, and transmits the data via the communication unit 10. The content is notified to the management side data communication terminal 25, and
When a command is received from the intelligent cubicle controller 25, it cooperates with the main controller 27 of the LAN 23 to perform calculations for predetermined power control, and, depending on the situation, sends the operating conditions of each machine and the above-mentioned information to the line condition setting section 55. The NC program or schedule change command is set, and the switch 20 for each load is controlled to open and close via the switch control section 56 at appropriate timing.

FIG. 8 shows an overview of the processing mainly performed by the power prediction section 29 of the intelligent cubicle controller 25.

In step 801, the load is monitored in response to the detection signal from the detector 5. In step 802, power schedules for each part are received from the line-side data communication terminals 14 to 17, and in step 803, the received power is predicted. .

This power forecasting does not simply extend the current power demand to estimate future power, but rather predicts the future power demand from the planned power demand of each machine, and the predicted value is dramatically more accurate. Become. For example, since it can be known that a 30 KVA motor will start rotating 10 minutes from the current time, it is possible to accurately predict the active and reactive power for 10 minutes from now. In addition, the power prediction unit 43 includes a fuzzy inference unit, and refers to the knowledge database 39 to estimate the interlocking relationships of various devices associated with the line according to the rough power schedule on the line side. It is possible to make accurate power predictions.

Therefore, in steps 804 to 806, the predicted power is compared with the management target value, and when the predicted power is likely to exceed the target value, three steps of power control are performed in steps 804 and subsequent steps.

The first stage of power control is the type that can most easily suppress power demand. Examples include blocking.

In this first-stage power control, the intelligent cubicle controller 25 asks the line-side data communication terminals 14 to 17 whether or not the first-stage power control is possible. It is executed by outputting a command from the cubicle controller 25 to the demand controller 3 or to other data communication terminals 14-19.

As an example of changing the load operation timing executed on the line side, for example, the time when a machine starts operating with a certain load amount,
Examples include shifting the time slightly from the time when peak power occurs, and reversing the execution order of machines A and B.

For example, punch press machines 31 arranged in series on a line
For A and the laser processing machine 31C, if punch processing is specified next to laser processing, the punch processing is performed first, giving priority to the laser processing. The reason for this is that, as shown in FIGS. 9 and 10, laser processing generally requires more power than punch processing. FIG. 9 shows the power characteristics of the punch press machine 31A, and FIG. 10 shows the power characteristics of the punch/laser combined processing machine 31B.

As shown in FIG. 10, laser processing requires more than 10 KW of power to start processing.

The reason why we decided to cut off unnecessary loads via the power control terminals 14 to 19 on the line side without using the demand controller 3 shown in FIG. 2 is to cut off the demand control power wiring 10 for a small amount of power. The wiring work is difficult, and even though the power is small, it is easier to manage the load on the line side. Furthermore, in this example, unnecessary loads can be cut off via the power control terminals 18 and 19 that do not have the data processing section 21, so that the data communication terminal 25 on the management side can perform remote control, so to speak. In short, the first stage power control is of a type that can easily shift the power peak and suppress the power demand without affecting the processing in any way.

The schedule can be changed automatically by the main controller 27 of the LAN 23. Furthermore, the automatic programming device 28 can easily change the program. The data processing section 21 of the data communication terminals 14 to 17 on the line side may appropriately cooperate with the control device of the connected processing machine to change the timing and order.

When the control state of a load is changed, the operating state of ancillary equipment such as a compressor may need to be changed in accordance with the changed state. In this case, in this example, the data communication terminal is connected to each load. Since the system is interposed, it is easy to respond by turning on the power to the required compressor and turning off the power to the unnecessary compressor.

FIG. 1 and FIGS. 11 to 14 are explanatory diagrams showing specific examples of procedures for changing production schedules. Figure 11 is a flowchart showing the transmission and reception status between the intelligent medium cubicle controller (ICC) and the LAN main controller (IMC), Figure 1 is a flowchart showing the procedure for changing the production schedule of the main controller, and Figure 12 is the flowchart showing the main controller An explanatory diagram of the power prediction chart displayed on the screen, and FIGS. 13 and 14 are explanatory diagrams of the schedule change screen.

In Figure 11, the intelligent cubicle
The controller 25 receives the production schedule from the main controller 27 (steps 1101 to 1105), and calculates the power prediction in step 1102. The calculation result is transmitted to the main controller 27 side so that it can be referenced at any time (step 1106).

Then, in step 1103, the intelligent cubicle controller 25 sets the predicted power P to the management target value P. When there is a possibility that Po≦P, in this state, a power schedule change command is output in step 1104 without immediately shifting to normal demand control. This command is for LAN23
is received on the main controller 27 side (step 10).
07), a procedure for changing the production schedule is taken in step 1108.

The production schedule change procedure performed by the main controller 27 is shown in FIG.

When the production schedule change request lamp is turned on in step 101, the operator sees this and turns on the salted oysters in step 102.

Then, in step 103, the power element #I chart is displayed on the screen 58 as shown in FIG.

In the screen 58 shown in FIG. 12, the horizontal axis indicates time, and the vertical axis indicates predicted power P. Assume that the current time is 10 o'clock.

In the chart of FIG. 12, the received power from 11:00 to 11:00 is at the management target value P due to the peak power of the line managed by LAN2B from 11:00 to 11:30. It has been shown that there is a risk of exceeding the

Therefore, when the operator gives a computation command in step 104, a change plan for the production schedule is automatically computed in step 105, and in step 105, as shown in FIG. 13 and FIG. A second proposed change is displayed.

The proposed change in FIG. 13 indicates that schedule A, which was scheduled for the line from 11:00 to 11:00, should be moved up and executed already from 10:00 to 10:00. By executing this schedule A earlier, the power demand P from 11:00 to 11:00 is set to the management target value P. It has also been shown that it is possible to reduce the

The proposed change in Figure 14 is for NC programs A and B on line i.
, C is changed to another schedule S2 by changing the execution order of the NC programs, and the execution time of NC program B with large power demand is 11.
The received power P is the management target value P to avoid coming between 11:00 and 11:00. This is to ensure that it does not exceed.

The operator should refer to the proposed changes in Figures 13 and 14,
In step 1106, an acceptable plan is adopted, and the production schedule can be changed. It is also possible to manually enter a proposed change in step 1107.

Next, in step 108, a change proposal is created according to the input contents of step 106 or step 107, and the change proposal created in step 109 is intelligently applied.
It is transmitted to the cubicle controller 25.

The intelligent cubicle controller 25 receives the transmission content from the main controller 27 in step 109 in FIG. 1 in step 1101 in FIG.
While newly calculating the power prediction in step 1102, the eighth
The power control shown in step 804 and subsequent steps in the figure will be performed.

In this way, the intelligent cubicle controller 25 not only communicates with the main controller 27 of the LAN 23, but also communicates with other data communication terminals 15, 1
6, 1.7, it is possible to communicate with a controller that controls one or more machines, to shift the operating timing of the machines located under the controller, and to change the program.

Referring again to FIG. 8, the second-stage power control in step 805 is power control that is activated when the demanded power is likely to exceed the target value even if the first-stage power control is performed.

In this second-stage power control, the demand controller 3 is operated in the same manner as in the conventional example for the lighting load that has been set in advance to be cut off in the second stage, and the predetermined load connected to the demand control power wiring 12 is operated. They are cut off one after another. All of the conventional shutoff orders and shutoff load setting methods can be used.

However, in this example, the demand control condition calculation unit 41
It is important that the control controller 3 is operated under the conditions set here. That is, in the power control system of this example, the data communication terminals 25.14 to 19 operate the demand controller 3 while emphasizing power control on the line side. Since a part of the side load can be cut off, the operating range of the demand controller 3 can be minimized accordingly.

The third stage power control in step 806 is control that is activated when the demanded power is likely to exceed the target value even if the second stage power control is performed.

In the third stage power control, in addition to the preset lighting load that can be cut off in the third stage, processing is slightly affected within the preset range, but the power control on the line side can help control demand. Power can be suppressed below the target value.

Examples of this include the aforementioned schedule change and program change, but these changes are more advanced than those in the first and second stages.

For example, when processing a product, it includes control such as temporarily stopping a machine so as to delay the processing of the product to the extent that the delivery date can be met. To this end, it is sufficient to allow the operator at the site where the product is processed to set a possible delay time for product completion based on the operator's judgment. Further, for this purpose, a machine time stop process is also taken, but the time stop here is an improved temporary stop described above, and no defective products are produced. As an extension of this, it also includes plaintext that is processed during the day and processed unattended at night.

As a result of the above, each data communication terminal 25.14-19
By interconnecting the grid, the peak value of power demand can be reasonably suppressed, making it possible to keep the power demand below the target value.

In the reactive power prediction process in step 807, the power prediction section 43 predicts the reactive power according to the machine operating status on the line side, and the capacitor switching condition calculation section 42 selects the capacitor according to the predicted reactive power. It calculates the switching conditions and controls the switching of the capacitor.

FIG. 15 is an explanatory diagram showing a reactive power prediction method.

In the figure, reactive power Q at time T1. When a certain machine is operated from time T1 and the reactive power increases by ΔQ, the predicted reactive power after time T1 is Q. It becomes 10△Q. Although this is the most basic concept, ΔQ can be determined as a function of time. In addition, the reactive power of the attached equipment can also be determined accurately. Other examples of operating schedules include a schedule in which a machine is to stop after a certain amount of time. In this case, it is generally predicted that the reactive power will decrease after a certain period of time. Further, even for portions where scheduled operations cannot be reported, a more approximate value can be fuzzy inferred using a knowledge database as appropriate.

In this example of power factor improvement, the reactive power can be accurately determined according to the machine's operation schedule, so the capacitor can be turned on or off appropriately, minimizing the line current of the power receiving equipment, and voltage can be maintained at a predetermined value, providing high-quality power to the production line.

[Effects of the Invention] As described above, since the present invention is a power control method for a production line as described in the claims, it is possible to reduce production efficiency by coordinating the power receiving and distribution equipment with the production line. Therefore, the power demand can be kept within the management target value.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing a production schedule conversion method related to the main part of the power control method for a production line according to the present invention, Fig. 2 is a block diagram showing a factory power reception and distribution system implementing the present invention, and Fig. 3 is a processing An explanatory diagram showing an example of a factory local area network system (LAN), Fig. 4 is a perspective view showing the external appearance of the intelligent cubicle controller, Fig. 5 is a block diagram showing its internal configuration, and Fig. 6
Figure 7 is a block diagram showing the task configuration of the power management section, Figure 7 is a block diagram showing details of the data communication terminal arranged for the load group on the line side, and Figure 8 shows an example of the power control method. Flowchart, Figure 9 is an explanatory diagram showing an example of the power characteristics of a punch press machine, Figure 10 is a diagram showing an example of the power characteristics of a punch press machine.
Explanatory diagram showing an example of power characteristics of a laser compound processing machine, 1st
Figure 1 is the Intelligent Association Cubicle. A flowchart showing the transmission/reception status between the controller (ICC) and the LAN main controller (IMC), Figure 12 is an explanatory diagram of the power prediction chart displayed on the main controller screen, and Figures 13 and 14 are diagrams of the schedule change screen. Explanatory diagram, FIG. 15 is an explanatory diagram showing a reactive power prediction method. 1... Power receiving and distribution equipment 2... Intelligent cubicle controller 3... Demand controller 4... Capacitor bank 11... Cubicle side data communication terminal 12...
...Demand codon roll power wiring 13...Non-control power wiring 25...Management side data communication terminal (intelligent cubicle controller) 43...Power prediction section 44...Power management section

Claims (1)

[Claims] A data communication terminal for power control is provided in a power receiving and distributing facility and a load side to which power is supplied from the power receiving and distributing facility to constitute a power control communication network, and the network and a network of a production line located on the load side. are connected to enable data communication, and when the power demand of the power receiving and distribution equipment is likely to exceed the management target value, the power demand is calculated by referring to a database that can calculate the power required for various production schedules. A power control method for a production line, characterized in that the production schedule of the production line is rearranged so as not to exceed a target value.