KR20210026373A - Measurement and Control System for FAST Demand Response - Google Patents

Abstract

The present invention relates to a measurement and control system for FAST DR. The measurement and control system for FAST DR comprises: a power/frequency measuring means (140, 240) measuring power and frequency supplied to the load (130, 230); controllers (100, 200) generating a control signal using power and frequency information received from the power/frequency measuring means (140, 240); and a power supply unit (310) receiving the control signal and adjusting the power supplied to the load (130, 230). When the frequency of the power supplied to the load (130, 230) falls below a normal power frequency, the controllers (100, 200) send a control signal for reducing the power supplied to the load (130, 230) to the power supply unit (310).

Description

Measurement and Control System for FAST Demand Response}

The present invention relates to a measurement and control system for operating FAST DR (DEMAND RESPOSE; demand response), and in more detail, it is possible to automatically and quickly manage demand response resources (power demand load) in the power market. It relates to a measurement and control system for FAST DR.

As awareness of the environmental pollution of existing thermal power generation and the safety of nuclear power generation has increased, new and renewable energy such as wind power, solar power and tidal power is being proposed as an alternative that is relatively safe and free from environmental pollution problems. However, compared to thermal power generation or nuclear power generation, new and renewable energy is inevitably more volatile in power supply (a fluctuation in the amount of generation that cannot be controlled due to changes in wind strength and amount of sunlight is bound to occur). If it expands according to the current trend, the volatility is expected to reach a maximum of 18 GW by 2030, which corresponds to the size of 18 nuclear power plants. If the power generation is not maintained stably and fluctuations occur in the power grid, it becomes difficult to maintain the normal frequency of the power grid (in the range of 59.8 Hz to 60.2 Hz based on domestic standards), and the power grid may collapse. It takes a long time. In order to prevent the above situation, when there is a fluctuation in the frequency of the power grid, the generation amount is controlled by operating a frequency tracking operation (Governor Free (GF)) or an automatic generation control operation (AGC).

However, as the proportion of new and renewable energy increases, there is inevitably a limitation in controlling the amount of power generation as described above, and thus the need to manage demand-responsive resources emerges. For the management of demand-response resources, the electricity demand resource trading market was opened from 2014. The power demand resource trading market is largely divided into peak reduction DR (Demand Respose), which must comply with the maximum power reduction order of the power exchange, and rate reduction DR, which voluntarily reduces power supply costs. Peak reduction DR is a method in which the demand management service provider (resource operation) and the power exchange contract the required reduction capacity in advance by fulfilling the mandatory reduction, and the demand management service provider obliges the load reduction when the power exchange issues a reduction order for the contracted capacity. to be. Charge reduction DR is a method of reducing demand resources when there is no reduction order from the power exchange and is cheaper than the general power generation bid price in the electricity market the day before.

In other words, the existing demand response resource management is operated in terms of power system peak and generation cost reduction. However, when a situation in which the frequency of the power grid is out of the normal frequency range is detected, the existing demand response resource management method that requests response from the power consumer has a limitation in achieving rapid stabilization of the power grid according to the abnormal frequency range.

Registered Patent Publication No. 10-1703296 (Announcement date: 2017.02.06.) Registered Patent Publication No. 10-0846396 (Announcement date: 2008.07.16.) Unexamined Patent Publication No. 10-2014-0091951 (Publication date: 2014.07.23.)

The present invention is to solve the problems of the prior art described above, and by automatically adjusting the power demand based on the frequency change of the power system, it is intended to increase the stability of the power system. In particular, it is another object to provide a measurement and control system for FAST DR (Demand Response) that can be directly used for demand response by automatically measuring power quantity and frequency data in a short period compared to conventional demand response resources.

The present invention relates to a measurement and control system for FAST DR, comprising: power/frequency measurement means (140,240) for measuring power and frequency supplied to loads (130,230); A controller (100,200) for generating a control signal using the power and frequency information transmitted from the power/frequency measuring means (140,240); And a power control means for receiving the control signal and adjusting the amount of power supplied to the loads 130 and 230, wherein the controller 100 or 200 includes a frequency of the power supplied to the loads 130 and 230 outside the normal power frequency range. It is characterized in that a control signal for changing the power supplied to the loads 130 and 230 is sent to the power control means.

The controllers 100 and 200 may transmit, to the demand management service provider system 300, control flag information regarding the magnitude and frequency of the measured power, and the operating state of the controllers 100 and 200.

The power control means may be a distribution control panel 110 used to supply power to a plurality of loads 130 (discontinuous method), and the controller 100 supplies power according to the degree of decrease of the power frequency. By calculating the number of blocked loads, a control signal for blocking power supply to a corresponding number of loads may be transmitted to the power distribution control panel 110.

Further, the power control means may be an inverter that adjusts the power supplied to the load 230 (continuous method), and the controller 200 determines an increase or decrease in the output frequency of the inverter, thereby increasing or decreasing the output frequency. It characterized in that the control signal to be sent to the inverter.

In addition, the power control means may be a load output increasing/decreasing device that controls the output current and the output voltage to control the power supplied to the load 230 (continuous method), and the controller 200 The load output increasing/decreasing device is characterized by sending a control signal for increasing/decreasing the output voltage and output current by calculating an increase/decrease amount of the output voltage and the output current.

Here, the controller 100 responds to the interruption of power supplied to the load within 10 seconds and maintains it for 30 seconds or longer, and then sends a return signal to resume normal power supply to the loads 130.

The controller 400 receives a control signal calculated based on the power reduction amount information provided by the central system 400 from the central system 400 and controls the power supplied to the load through the power supply unit 310. (AGC method), the controller 100 responds to the interruption of power supplied to the load within 30 seconds and maintains it for at least 30 minutes, and then sends a return signal to resume normal power supply to the loads 130. .

The measurement and control system for FAST DR according to the present invention periodically measures the power frequency applied to the load, and performs demand response (Demnad Respose; changes the size of the load connected to the power grid) based on the measured power frequency. By doing so, the problem of abnormal fluctuation (decrease and increase or decrease) of the power frequency is quickly solved, and the power grid can be stably operated.

1 shows an apparatus for operating a power system according to the prior art.
2 shows a control state of the GF method in the measurement and control system for FAST DR according to the present invention.
3 shows the power reduction ratio in the discontinuous system of the GF method.
4 shows the power reduction ratio in the continuous system of the GF method.
5 shows a control state of the AGC method in the measurement and control system for FAST DR according to the present invention.

Hereinafter, the overall configuration of the measurement and control system for FAST DR according to the present invention will be described with reference to the drawings. Specific structural or functional descriptions presented in the embodiments of the present invention are exemplified only for the purpose of describing the embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described in the present specification, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

2 shows the overall configuration of a measurement and control system for FAST DR according to the present invention. A line between each element indicates a path for transmitting a signal between the elements, and it will not be difficult for a person skilled in the art to understand that both wired and wireless are possible. First, let's briefly look at the function of each element. The controller 100 or the microcontroller unit (MCU) receives the size and frequency data of the power applied to the load 130 from the power/frequency measurement means 140 and stores it in the database 310 of the demand management service provider server 300 In addition, by sending an operation/stop/output increase/decrease signal to the power distribution control panel 110 or the power supply unit 210 (inverter or load output increase/decrease device) based on the power and frequency data, the amount of power applied to the load is adjusted. It is an element to do. This may be manufactured with a self-designed board, but it will be understood by those skilled in the art that it may be implemented using a module such as Raspberry Pi or Arduino.

The distribution control panel 110 is an element that blocks power supplied to some or all of a plurality of loads connected to the switchboard or controls to supply power based on a control signal sent from the controller 100 (relay module control Element). Continuous power control means 210 such as an inverter or a load output increase/decrease device increases or decreases the output frequency (in the case of an inverter) based on the control signal sent from the controller 200, or increases or decreases the output voltage and output current (load output In the case of an increase/decrease device), it is an element that controls the power supplied to loads. Both the distribution control panel 110 and the continuous power control means 210 are elements that control power supplied to the load, and these are collectively referred to below as a power supply unit.

The power/frequency measurement means (140,240) is a means for measuring the magnitude and frequency of the power supplied to the load. In general, a highly reliable digital aggregate meter is used, and a self-developed measuring instrument and a product having similar functions are used. Can be used. The controllers 100 and 200 request power and frequency information from the power/frequency measurement means 140 and 240 at a certain period (preferably 2 seconds), and the power/frequency measurement means 140 and 240 Frequency information is provided to the controller 100. As a communication method, Modbus RTU RS-485 or a similar communication protocol can be used.

The demand management service provider system 300 makes contracts with various power demand sources (common housing, industrial, commercial facilities, educational facilities, agricultural facilities, etc.), and, if necessary, gives an instruction to increase or decrease power to the contracted power consumer, monitors the amount of reduction, etc. As a system operated by a demand management business operator, the controller 100 can communicate with the controller 100 by a communication method such as MQTT or HTTP.

The loads 130 and 230 are factors that consume power supplied through the power grid, and include various types of power consumption factors such as apartment houses, industrial facilities, commercial facilities, educational facilities, agricultural facilities, and the like.

The central system 400 is a system operated by a power exchange or a power company, and when data on the load status (power and frequency used) is received from the demand business management service provider system 300 and it is necessary to reduce the load power. As an element that makes a request to the demand business management service provider system, the central system 400 may communicate with the demand business management service provider system 300 through MQTT, HTTP, or a similar communication method.

Hereinafter, an operation method of the measurement and control system for FAST DR according to the present invention will be described with reference to the drawings. In the measurement and control system for FAST DR according to the present invention, the controllers 100 and 200 themselves control demand response based on a relatively short cycle (response within 10 seconds and maintains more than 30 seconds) without intervention of the central system 400. It can be operated in a governor free) method and an automatic generation control (AGC) method in which demand response is controlled based on a relatively long period (response is maintained for tens or more minutes within 30 seconds) under the control of the central system 400. Here, GF and AGC are terms used for the method of controlling the generation amount of the generator, and are not terms applied to demand response, but for convenience based on the similarity of mechanisms, the terms GF and AGC method are used for acceptance response. .

[GF method]

The GF method responds to demand based on a relatively short period (response within 10 seconds, maintains 30 seconds or more, preferably maintains 30 to 35 seconds), and requests/requests from the demand management service provider system 300 and the central system 400 The controllers 100 and 200 control the power supplied to the load based on the data received from the power/frequency measuring means 140 and 240 without a command.

First, in FIG. 2, NC shows a discontinuous system in which power cut off of a load is discontinuously performed, and CO shows a continuous system in which power cut off of a load is continuously performed. Although the continuous system (CO) and the discontinuous system (NC) are shown to be connected to the demand management service provider system 300 one by one, this is an example, and a plurality of continuous systems (CO) and a discontinuous system in one demand management service provider system 300 It is not difficult for a person skilled in the art to understand that (NC) may be connected to form a measurement and control system for FAST DR, or that a FAST DC system may be configured with only a discontinuous system (CO) or a continuous system (CO). I will be able to.

The discontinuous system (NC) is a system in which power supplied to a load is discontinuously cut off, and the controller 100 cuts off some or all of the plurality of loads 130 connected to the control panel 110 for distribution. It regulates the power supplied to the load. On the other hand, the continuous system (CO) is a continuous control of the power supplied to the load, the controller 200 is a continuous power control means 210 (inverter or load) that adjusts the amount of power supplied to the load 230 The power supplied to the load is adjusted by controlling the output increase/decrease device).

Hereinafter, in the description process, common operations in the continuous system CO and the discontinuous system NC will be collectively described. Specifically, the power and frequency supplied to the loads 130 and 230 by the power/frequency measurement means 130 and 230 are measured (H1, G1), and the measured power and frequency values are transmitted to the controllers 100 and 200 (H2, G2). ). At this time, the controllers 100 and 200 request data from the power/frequency measurement means 130 and 230 in a predetermined time unit (for example, 2 seconds), and the power/frequency measurement means 130 and 230 transmit the data to the controller in response to the above request. It will be transmitted as (100,200). If a serial communication method such as Modbus 485 RTU is used between the power/frequency measurement means and the controller, due to the characteristics of serial communication, noise may occur between the controllers (100,200) and the power/frequency measurement means (140,240), resulting in disconnection of communication. In order to minimize this, methods such as lottery transformer installation, termination resistor installation, communication signal grounding, and power grounding can be introduced. The controller (100,200) may transmit information from one power/frequency measurement means, but since it must be able to transmit information from a plurality of power/frequency measurement means (140,240), the power/frequency measurement means (140,240) Be recognizable. Therefore, each of the power/frequency measuring means 140 and 240 has a unique ID. And, if the controller receives power and frequency data, it must be able to recognize the data to at least 2 decimal places, and it must be able to recognize and convert the data into decimal numbers. Furthermore, it is preferable that the controllers 100 and 200 are equipped with a time recognition and synchronization module such as a Real Time Clock (RTC) module so that the measured time can be recognized.

When the frequency is within the normal range (near 60Hz), the controllers 100 and 200 do not generate any control signals, but when it is determined that the power and frequency are out of the normal range, the controllers 100 and 200 adjust the power supplied from the load. The control signal for this is sent to the power supply unit 310 (H3, G3). Here, the power supply unit 310 is used in a sense encompassing the power distribution control panel 110 or the power supply unit 210 (inverter or load output increasing/decreasing device).

-Discontinuous system (NC)-

In the discontinuous system NC, the controller 100 reduces the power supplied to the load based on the power frequency data. As shown in FIG. 3, a reduction ratio to power frequency is preset and tabled, and a reduction ratio is calculated based on the frequency data received from the power/frequency measuring means 140. For example, when the power frequency drops to 59.9, the reduction ratio of the power supplied to the load for frequency recovery should be 62%, and the power supplied to some or all of the plurality of loads 130 is cut off or operated. Or increase or decrease the output. Since the power supplied to each of the loads 130 is cut off in an ON/OFF form, as shown in FIG. 3(b), the reduction ratio according to the frequency change rate is discontinuously determined in the form of a step. The power reduction ratio is determined by calculation within the controller 100, and a signal is sent to the distribution control panel 110 (H3) to operate the relay module to achieve the corresponding power reduction ratio. The power supplied to) is cut off (H4). In order to meet the characteristics of the table or diagram shown in FIG. 3, the rated capacity and the amount of reduction possible of the equipment constituting the load 130 must be identified in advance. The relay module's load-blocking operation method includes a single-shot (about 1 second) operation and a continuous operation (continuous operation until the cut-off point ends), and the selection of the operation method is based on the configuration of the distribution control panel 110 or the load 130 ) Can be selected according to the characteristics of the equipment constituting it.

The load 130 responds within 10 seconds after the controller 100 generates the control signal, and the power is cut off for 30 seconds or more according to the control signal. When 30 seconds elapse after the power supply to the specific load 130 is cut off, the controller 100 sends a return signal to the power distribution control panel 110 in a normal state (a state in which normal power is supplied to the load 130). Return to (H5). The relay module's load operation operation method includes single-shot (approximately 1 second) operation and non-operation (not operation when the cutoff point is over), and selection of the operation method is based on the configuration of the distribution control panel 110 or the load 130. It can be selected according to the characteristics of the equipment to be configured.

-Continuous system (CO)-

In the continuous system (CO), the controller 200 generates a signal for controlling the frequency output (inverter) or output voltage and current (load output increasing/decreasing device) of the continuous power control means 210 (inverter or load output increasing/decreasing device). The power supplied to the load is adjusted by adjusting the frequency output (inverter) or the output voltage and current (load output increasing/decreasing device) of the power supply means 210 (G3) (G4). The continuous system CO differs from the non-continuous system NC in that the reduction ratio according to the frequency change rate is continuously determined as shown in the table and diagram of FIG. 4. A power reduction rate corresponding to the table or table of FIG. 4 may be determined using the received power frequency data, and the output frequency of the inverter 210 is controlled based on the determined power reduction rate. Therefore, the power supply means 210 receives an analog input signal (at least one of 0-10VDC / 4-20mA) or outputs a frequency (inverter) or outputs voltage and current using a communication protocol such as Modbus RTU 485. A function (load output increasing/decreasing device) must be installed (such a function is provided in most conventional inverters and load output increasing/decreasing devices). In order to accurately control the power consumption of the load 210 facility according to the inverter output frequency, the similarity rule for shaft power must be used. This means that the shaft power is proportional to the cube of the change in the number of revolutions, and by using this, the frequency according to the target power can be obtained.

However, since the maximum frequency input allowable range of the shaft power is mostly 0-60Hz, the inverter output frequency according to the target amount of power is set to 0Hz if it is negative, and to 60Hz if it exceeds 60Hz. However, since the minimum and maximum frequency range may vary according to the characteristics of the equipment, in this case, it is applied according to the characteristics of the relevant equipment.

Even in a continuous system, control with a load output increase/decrease device 210 such as an inverter to return to a normal output state after a certain period of time (for example, 30 seconds) after the supply power control for a specific load 230 is made. It sends a return signal to the panel or to the existing system (eg PLC) (G5).

The controllers 100 and 200 provide power data, control completion, and information on whether the controller is in a state in which the control is being executed or in a standby state (control flag) at a predetermined time interval (generally 2 seconds). The transmission is transmitted to the system 300 (H6), and the demand management system 300 stores the received information in the database 310 and transmits the received information to the central system 400 (H7).

In the above system, the power supplied to the load is controlled in such a way that some of the plurality of loads are cut and put in stages as shown in FIG. It can be done (hereinafter referred to as "UFR non-linked"), but at the time when the entire power supplied to one or more loads falls below a specific frequency (59.7Hz), it is cut off at once (the power supplied to all loads is 100 % Cutoff) can also be used to control power (hereinafter referred to as "UFR-linked"). For reference, UFR (Under Frequency Relay) is a relay that stops the system when the frequency is lowered due to an overload of the generator.Although it is a technology applied to power supply (generator) rather than demand response, the present invention applies a similar concept to demand response. It is done.

[AGC method]

While the GF method is controlled without an instruction from the central system 400 or the demand management service provider system 300 based on a relatively short period (response within 10 seconds and maintains more than 30 seconds), the Automatic Generation Control (AGC) method Control is performed by a control signal from the central system 400 or the demand management service provider system 300 (maintains tens or more minutes of response within 30 seconds).

Excluding the overlapping part with the GF method, the explanation will focus on the part with the difference. The demand management service provider system 300 receives a reduction signal ID from the central system 400 (information that enables identification of the reduction signal and is a unique value that cannot be duplicated), a request ID (communication request from the central system to the demand management service provider server). This is information that makes it possible to identify the time, and is a unique value that cannot be duplicated), command signal type (divided into a test signal and an actual signal, and transmits FAST-DR command information to the controller only in the case of an actual reduction signal. In this case, data is stored in the database after communication), data list, signal issuance status (divided into begin and end. Begin is the identification factor when the first signal is generated from the central system to the demand management service provider server within one reduction signal ID) end is an identification factor in the case of generating the last signal to the demand management service provider server within one reduction signal ID from the central agency server), demand response resource ID (information that enables the identification of demand response resources, and will be duplicated. This is a unique value that cannot be used), FAST DR issuance time, CBL (Customer Base Line; load used as the basis for calculation of reduction amount, for example, the average value for 20 seconds from 2 seconds before FAST-DR issuance), target power amount or It receives (A1), calculates distribution optimization for distribution to a plurality of controllers (100, 200) and performs transmission (A2, A3). Distribution optimization calculation means calculating the optimum frequency output value or output voltage, current and power value for each controller, with the target power amount or power reduction amount between the CBL and the reference value.

That is, in the AGC method, the demand management service provider system 300 allocates the power reduction amount to the plurality of controllers 100 and 200 according to the request of the central system 400, and each controller 100 and 200 achieves the allocated reduction amount. It is to generate a control signal for. Alternatively, the central system 400 gives a command (turn it off for a few minutes) to the demand response resource for OFF time, and within 10 minutes, it is possible to perform a standby replacement operation that operates during the OFF time by responding. Since the process of controlling the power supplied to the load after the control signal is generated is not different from that described in the GF method, an additional description will be omitted.

100,200: controller 110: control panel for distribution
130,230: load 140,240: power/frequency measurement means
210: continuous power control means 300: demand management operator system 400: central system

Claims (8)

As for a measurement and control system for FAST DR,
Power/frequency measuring means (140,240) for measuring the power and frequency supplied to the loads (130,230);
A controller (100,200) for generating a control signal using power and frequency information transmitted from the power/frequency measuring means (140,240); And
Including; power control means for adjusting the amount of power supplied to the loads (130, 230) by receiving the control signal,
The controllers 100 and 200 transmit a control signal for changing the power supplied to the loads 130 and 230 to the power control means when the frequency of the power supplied to the loads 130 and 230 is out of the normal power frequency range. Measurement and control system for.
The method according to claim 1, wherein the controller (100, 200) transmits control flag information about the measured power magnitude, frequency, and operating state of the controller (100, 200) to the demand management service provider system 300. Measurement and control system.
The method according to claim 2, wherein the power control means is a distribution control panel (110) used to supply power to a plurality of loads (130),
The controller 100 calculates the number of loads that block power supply according to the degree of decrease of the power frequency, and transmits a control signal for blocking power supply to the corresponding number of loads to the distribution control panel 110. Measurement and control system for FAST DR, characterized in that.
The control signal according to claim 2, wherein the power control means is an inverter that adjusts power supplied to the load 230, and the controller 200 determines an increase/decrease amount of the output frequency of the inverter, thereby increasing or decreasing the output frequency. Measurement and control system for FAST DR, characterized in that sending to the inverter.
The method according to claim 2, wherein the power control means is a load output increase/decrease device that adjusts the power supplied to the load 230, and the controller 200 calculates an increase/decrease amount of the output voltage and the output current of the load output device. And a control signal for increasing or decreasing the output voltage and output current to the load output increasing/decreasing device.
The method according to any one of claims 3 to 5, wherein the controller 100 responds to interruption of power supplied to the load within 10 seconds and maintains it for 30 seconds or longer, and then sends a return signal to supply normal power to the loads 130 Measurement and control system for FAST DR, characterized in that to resume.
The power supply unit 310 according to any one of claims 1 to 5, wherein the controller 400 receives a control signal calculated based on the power reduction amount information provided by the central system 400 from the central system 400. Measurement and control system for FAST DR, characterized in that to control the power supplied to the load through the.
The method according to claim 7, wherein the controller 100 responds to interruption of the power supplied to the load within 30 seconds and maintains it for tens or more minutes, and then sends a return signal to resume normal power supply to the loads 130. Measurement and control system for FAST DR.

Images