KR20040024166A - Detecting Controll Method And System of Maximum Power Supply - Google Patents

Abstract

PURPOSE: A method and a system are provided to reduce costs by using the existing local area network, while allowing for use of control program of computer. CONSTITUTION: A system comprises a demand meter(404) for metering the power being used in loads(405); a computer(401) for taking, as an input, the power metered by the demand meter, storing the input power for a predetermined time period, estimating the power to be demanded by the loads in the next cycle, and transmitting load on/off commands in accordance with the result of the comparison between the estimated power and the preset power of maximum demand; a protocol converter(406) connected to the computer through a local area network; and a programmable logic controller(407) connected to the protocol converter through a communication cable, wherein the programmable logic controller receives, through the protocol converter, the on/off commands from the computer and transmits the command to the corresponding load.

Description

Detecting Controll Method And System of Maximum Power Supply

The present invention relates to a method and system for monitoring and controlling the maximum demand power, and more specifically, to an ON / OFF command to a programmable logic controller connected to a load through a pre-installed LAN. To a maximum demand power monitoring and control method and system for controlling the load.

Conventionally, when the Demand Meter delivers the power currently being used to the Demand Controller, the peak demand power monitor controller calculates the predicted power that is expected to be demanded and the predicted power is the maximum demand. When it is determined that the power will be exceeded, the power supply is cut off according to the priority of each stored load so as not to exceed the maximum demand power.

1 is a block diagram of a conventional maximum demand power monitoring controller (Demand Controller). In accordance with the periodic signal of the timer unit 102, the integrated power meter 101 measures the power used by the load 108 and transmits it to the input unit 103, and the input unit 103 transmits this value to the arithmetic processing unit 104. do. The set value memory unit 110 stores values such as demand time limit (for example, 15 minutes), set power, and the like, and transmits these values to the arithmetic processing unit 104. The calculation processing unit 104 calculates the predicted power, which is an estimate of the power used next time, based on the used power delivered from the input unit 103 and the demand time limit transferred from the set value memory unit 110, and the value is converted into the set power and the set power. In comparison, when it is predicted that the set power is exceeded, the command is transmitted to the output controller 105, the load 108 is turned off (OFF) at the interruption priority set in the set value memory unit 110, and the alarm controller 107 ) Signals buzzer 109 and buzzer 109 generates an alarm. If it is determined that the predicted power does not exceed the set power, the OFF load 108 is turned ON again.

2 is a block diagram of the maximum demand power monitoring and control method of the wire installation method using the conventional maximum demand power monitoring and control device 201. The load 205 of each building (eg air conditioner) and the maximum demand power monitoring control device 201 are connected by wires 204.

Therefore, the labor cost and material costs involved in directly laying the wire 204 is expensive, and also because the wire 204 to be installed in the ground or high above the ground has the disadvantage that additional cost is required. In addition, when the distance between the maximum demand power monitoring control device 201 and the building is about 300m or more, there is a disadvantage that a voltage compensation device (not shown) according to the voltage drop is required. In addition, there is a risk of disconnection because the distance of the wire is far, and there is a disadvantage that it is difficult to adequately meet the scalability and user's demand by using a packaged program inside the maximum demand power supervisory control device 201.

3 is a block diagram of a maximum demand power monitoring and control method of the wireless installation method using the conventional maximum demand power monitoring and control device 301. In the case of the wireless installation method, the wireless terminal receiver 306 is attached to all the loads 305 of the building, and the maximum demand power monitoring controller 301 is attached with a wireless transmission controller 304 to monitor the maximum demand power monitoring controller ( The signal 301 is transmitted from the wireless transmission controller 304 to the wireless terminal receiving device 306 of the load 305 to control the load 305. Therefore, the wireless laying method has no wire laying cost or risk of disconnection, but the cost of the wireless terminal receiving device 306 and the wireless transmission controller 304 is added, and the wireless terminal receiving device 306 and the wireless transmission controller 304 are provided. If the distance is too long (approximately 1km or more), high frequency signals must be used, so a manager must be provided, such as being restricted by the Ministry of Information and Communication.

In addition, hospitals, military units, universities equipped with various experimental devices, etc., may cause malfunction of the devices due to frequency interference. This wireless installation method also uses a packaged program inside the maximum demand power supervisory control device 301. This makes it difficult to respond appropriately to scalability and user needs.

Therefore, the present invention takes a wired method, but saves money by using an existing LAN installed in each building without installing new wires, and uses a separate control program of a computer without using a maximum demand power supervisory control device. The purpose is to respond more quickly and appropriately to scalability and user needs.

1 is a configuration diagram of a conventional maximum demand power monitoring control device,

2 is a block diagram of a maximum demand power monitoring and control method of the wire laying method using the conventional maximum demand power monitoring control device,

3 is a block diagram of a maximum demand power monitoring and control method of the wireless installation method using a conventional maximum demand power monitoring control device,

4 is a configuration diagram of a maximum demand power monitoring and control system according to the present invention;

5 is a flowchart of maximum demand power monitoring and control according to the present invention.

※ Brief description of the main parts of the drawing ※

101, 202, 302, 404: Integrated power meter 102: Timer

103: input unit 104: arithmetic processing unit

105: output control unit 106: load control unit

107: alarm control unit 108: load

109: buzzer 110: set value memory

201, 301: Maximum Demand Power Supervisory Controls

203, 303, 403: power line 204, 408: electric wire

205, 305, 405: Load 304: Wireless Transmission Controller

306: wireless terminal receiver 401: computer

402: A / D converter 406: protocol converter

407: programmable logic controller 410: LAN

In order to achieve this object, the maximum demand power monitoring and control system according to the present invention includes an integrated power meter for measuring the power being used at the load; After receiving the measured power from the integrated power meter and storing it at regular time intervals, calculate the predicted power expected to be used by the load in the next time period, and compare the set power set to the predicted power and the maximum used power to turn on the load. A computer sending an on / off command; A protocol converter connected to a computer and a LAN; And a programmable logic controller (PLC) connected to the protocol converter by a communication cable and receiving the on / off command of the computer through the protocol converter and transmitting the same to a corresponding load.

In addition, the maximum demand power monitoring and control method according to the present invention comprises the steps of measuring the power consumption of the load and storing at a predetermined time period; Calculating the predicted power for the load to use in the next time period from the used power of the load stored in the predetermined time period; Comparing the preset set power with the predicted power and the maximum used power of the load; And when the predicted power is greater than the set power, the address of the address and load control means on the LAN in which the load is located is searched in the order of the load to be stored off, and then turned off to the corresponding LAN port. When the OFF command is transmitted and the predicted power is smaller than the set power, the address and load control on the LAN in which the load is located in the reverse order of the previously stored loads among the OFF loads. Retrieving a contact of the means, and transmitting an ON command to the corresponding LAN port.

Preferably, calculating the predicted power comprises predicting a use power function of the load over time from the use power of the stored load at periodic time intervals; And

And calculating a predicted power by substituting a period value of a next time into a function of the power used of the load.

Preferably, after sending the ON / OFF command, after checking the response several times, if there is no response, the next rank load is searched and the address and load control means on the LAN where the load is located. The method may further include transmitting an ON command to the corresponding LAN port by searching for the contact point.

Hereinafter, the present invention will be described in detail with reference to the drawings.

4 is a block diagram of the maximum demand power monitoring and control system according to the present invention.

In the present invention, a programmable logic controller (PLC) 407 is used as a control means of the computer 401 and the load instead of the conventional maximum demand power monitor controller. The integrated power meter 404 measures the power used in the load 405. This value is converted into a digital value via the A / D converter 402, and this value is transmitted to the computer 401 via RS-232C.

RS232C (Recommended Standard 232 Revision C) is a standard interface that transmits data serially and is standard on most personal computers (PCs). The RS232C interface standard is originally intended to connect a data terminal device and a modem (modulator / demodulator). The personal computer uses a part of the RS232C standard to simplify the connection.

The computer 401 calculates the predicted power to be consumed by the load in the next time period using the power used up to the present time periodically measured and measured by the integrated power meter, and compares the control signal with the set power set to the maximum allowable LAN. The programmable logic controller 407 controls each load by transferring the data to the programmable logic controller 407 through the LAN 410.

Communication between computer 401 and programmable logic controller 407 is by protocol converter 406. The connection of the programmable logic controller 407 and the protocol converter 406 is also by RC-232C.

The control method will be described below. 5 is a flowchart of maximum demand power monitoring and control according to the present invention.

The power consumption being used from the integrated power meter 404 is checked (S501), and these values are stored in the computer 401 in units of 15 minutes (S502). The computer 401 calculates the predicted power of the next period using this stored value (S503). Extrapolation is used for prediction. Extrapolation is a method of estimating the position of two points A and B on a curve and another point P on a portion defined by A and B when several points are known. Apply it.

The predicted value is compared with the preset set power (S504), and when it is determined to exceed, the programmable logic controller 407 which is an address and load control means on the LAN LAN 410 of the load to be sequentially OFF. ) Is searched for in the database of the computer 401 (S505).

A command to turn off the programmable logic controller 407 is sent to the corresponding LAN (LAN, 410) port (S507), and the response of the programmable logic controller 407 is checked (S508). If there is no response, send an OFF command again (S507). If there is a response, the control is completed (S509). If there is no response several times, an error message is sent to the database (S511), the load of the next rank is searched from the database (S512), and the LAN of the load ( The address on the LAN 410 and the contact point of the programmable logic controller 407 are retrieved from the database (S506), and an OFF instruction is sent (S507).

If it is determined that the predicted power does not exceed the set power, the database searches for an address on the LAN LAN 410 and a contact point of the programmable logic controller 407 of the load to be turned on again (S510).

A command to turn on the programmable logic controller 407 is transmitted to the corresponding LAN (LAN, 410) port (S507) and the response of the programmable logic controller 407 is checked (S508). If there is no response, it sends back an ON command (S507). If there is a response, control is completed (S509). If there is no response several times, an error message is sent to the database (S511), the next rank load is retrieved from the database (S512), and the LAN of the load In step S507, an address on the address 410 and a contact point of the programmable logic controller 407 are searched in the database, and an ON command is sent (S507).

On the other hand, the embodiments of the invention disclosed in the specification and drawings are merely illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the invention. It is apparent to those skilled in the art that other variations based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

The present invention takes a wired method, but saves money by using an existing LAN line installed in each building without installing new wires, and uses a separate control program of a computer without using the maximum demand power monitoring control. Respond more quickly and appropriately to your needs.

Claims (4)

Maximum demand power monitoring and control system, An integrated power meter for measuring the power being used at the load; After receiving the measured power from the integrated power meter and storing it at predetermined time intervals, calculates the predicted power expected to be used by the load in the next time period, and compares the set power set to the predicted power and the maximum used power. A computer transmitting an on / off command of the; A protocol converter connected to the computer by a LAN; And A programmable logic controller (PLC) connected to the protocol converter by a communication cable and receiving an on / off command of the computer through the protocol converter and transmitting the received command to a corresponding load; Maximum demand power monitoring and control system comprising a. Measuring the power used by the load and storing the load at a predetermined time period; Calculating a predicted power for the load to use in a next time period from the used power of the load stored in the predetermined time period; Comparing the predicted power with a set power set to a maximum used power of the load; And When the predicted power is greater than the set power, the address of the address and load control means on the LAN in which the load is located is searched in the order of the load to be turned off, and turned off to the corresponding LAN port. When the (OFF) command is transmitted and the predicted power is smaller than the set power, the address on the LAN in which the load is located in the reverse order of the load to be stored OFF among the loads that are OFF. Searching for a contact point of the load control means and transmitting an ON command to a corresponding LAN port; Maximum demand power monitoring and control method comprising a. 3. The method of claim 2, wherein calculating the predicted power comprises: predicting a use power function of the load over time from the use power of the stored load at periodic time intervals; And Obtaining a predicted power by substituting a period value of a next time into a function of a used power of the load; Maximum demand power monitoring and control method comprising a. The method of claim 2, wherein after the ON / OFF command is transmitted, the response is checked several times, and if there is no response, the next rank load is searched for and the address and load on the LAN where the load is located. Searching for a contact point of a control means and transmitting an ON command to a corresponding LAN port; Maximum demand power monitoring and control method characterized in that it further comprises.