KR102634578B1 - Method for managing voltage of voltage regulator - Google Patents

Abstract

The present invention discloses a method for managing the voltage of a voltage regulator. The voltage management method of the voltage regulator of the present invention includes a first step in which the control unit derives the amount of reactive power of the distributed power source required to maintain the voltage of the distribution system at the specified voltage based on the active power, which is the amount of power generation compared to facility capacity; A second step in which the control unit derives a reactive power standard to reduce reactive power compared to the maximum output of reactive power that satisfies the active power standard and the minimum bandwidth of the voltage regulator; A third step in which the control unit derives the optimal reactive power value required for each history based on reactive power; And a fourth step in which the control unit derives the setting value of the voltage adjustment device based on the optimal reactive power and the connection point voltage.

Description

Voltage management method of voltage regulator {METHOD FOR MANAGING VOLTAGE OF VOLTAGE REGULATOR}

The present invention relates to a voltage management method of a voltage regulator, and more specifically, to a method of managing the voltage of a voltage regulator, and more specifically, to a method of controlling the voltage of a voltage regulator, which is installed in a next-generation distribution management system (Advanced Distribution Management System, ADMS) and changes to system conditions (load/generation, etc.) based on historical data of the power system. ) to satisfy all system conditions as much as possible in order to supply the regulated voltage to consumers, reflect actual situations that may occur by considering the operating speed of each device, and minimize the output of unnecessary reactive power from distributed power sources as well as the role of each device. This relates to a voltage management method of a voltage regulator that manages the voltage by deriving the setting value of the voltage regulator to enable sharing.

In general, it is impossible to continuously supply a constant voltage to consumers (i.e., users). This is because voltage drops occur in each part of the power system from the generator to the consumer. This voltage drop is affected by the size of the load current, which is always changing, and varies depending on the power factor, distribution, and system configuration.

Therefore, the voltage regulator defines the range that obtains satisfactory output under conditions slightly higher or lower than the rated voltage specified in the electric appliance as the allowable voltage and performs the function of economically maintaining this range.

For reference, in order to simultaneously maintain the voltage supplied to each user through a single distribution line within the allowable range, the size distribution of the load current must be identified and controlled to provide appropriate voltage compensation by a voltage regulator when the load changes. However, most users receive power from the low-voltage system, and it is difficult to know the exact degree of voltage fluctuation that occurs in the low-voltage system due to the complexity of the low-voltage system and load fluctuations.

As a result, since the degree of voltage fluctuation of the low-voltage system is not known, it is difficult to determine the voltage maintenance range (i.e., high-voltage operating range) of the high-voltage system.

This also affects the proper operation of the voltage regulator that operates based on the voltage of the high-voltage system, and the resulting voltage control based on the inaccurate voltage operation standards of the high-voltage system cannot guarantee appropriate voltage supply to low-voltage system users. Uncontrollable problems arise.

Meanwhile, a number of voltage regulators are currently installed in distribution lines, but in the past, it is difficult to consider the mutual influence between multiple voltage regulators, so they are operated by individual control. Due to the limitations of the conventional technology, voltage problems due to load fluctuations, etc. may occur. In this case, there was a problem of excessive investment in facilities to solve this voltage problem.

The background technology of the present invention is disclosed in Republic of Korea Patent No. 10-1686296 (registered on December 7, 2016, voltage stability management device and method for power system).

When supplying regulated voltage to consumers by controlling the transmission voltage through OLTC (On Load Tap Changer) to manage the voltage of the distribution system, voltage problems are increasing due to the increase in the connection of new power facilities such as distributed power sources and electric vehicles to the distribution system. The situation is difficult.

In addition, it is possible to solve voltage problems through the voltage management function of distribution automation, but in order to properly demonstrate the performance of distribution automation, extensive communication facilities to understand the distribution system situation and computer facilities to process large amounts of data in real time and calculate optimal solutions are required. It is necessary, but it involves enormous costs, and improving voltage quality through facility reinforcement also involves enormous costs, which limits its application.

The present invention was created to improve the problems described above, and the purpose of the present invention according to one aspect is to install a system that is installed in a next-generation distribution management system (Advanced Distribution Management System, ADMS) and changes based on the history data of the power system. In order to supply the regulated voltage to consumers in certain situations (load/generation, etc.), it satisfies all grid situations as much as possible, reflects actual situations that may occur by considering the operation speed of each device, and minimizes the output of unnecessary reactive power from distributed power sources. In addition, it provides a voltage management method of the voltage regulator that manages the voltage by deriving the setting value of the voltage regulator to enable division of roles for each device.

The voltage management method of the voltage regulator according to one aspect of the present invention includes a first step in which the control unit derives the amount of reactive power of the distributed power source required to maintain the voltage of the distribution system at the specified voltage based on the active power, which is the amount of power generation compared to the facility capacity. ; A second step in which the control unit derives a reactive power standard to reduce reactive power compared to the maximum output of reactive power that satisfies the active power standard and the minimum bandwidth of the voltage regulator; A third step in which the control unit derives the optimal reactive power value required for each history based on reactive power; And a fourth step in which the control unit derives the setting value of the voltage adjustment device based on the optimal reactive power and the connection point voltage.

In the present invention, the voltage regulator is characterized by including one or more of an On Load Tap Changer (OLTC), a Step Voltage Regulator (SVR), a distributed power source, and an Energy Storage System (ESS).

In the present invention, the setting value of the voltage regulator is characterized by including LDC parameters of OLTC and SVR, and operating reference voltage values of distributed power and ESS.

The present invention is characterized in that in the first step, active power and OLTC LDC (Line Drop Compensator) are optimized and obtained through an objective function that minimizes voltage violation with OLTC bandwidth as a constraint.

In the present invention, the first step is defining initial values of variables for obtaining an active power standard; After defining the initial values of the variables, maximizing the bandwidth to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth; Comparing the bandwidth among the LDC settings obtained by maximizing the bandwidth with the minimum bandwidth set by the user; According to the result of comparing the bandwidth and the minimum bandwidth, if the minimum bandwidth is large, saving the current settings and adjusting the control frequency and amount of distributed power; And after adjusting the control frequency and amount of distributed power, comparing the amount of change in active power and the size of active power to derive the active power standard and storing the final active power standard and LDC when the termination condition is satisfied. do.

In the present invention, the termination condition for deriving the active power standard is characterized by comparing whether the amount of change in active power is less than a specific value or whether the active power is less than 0 or more than 1.

In the present invention, if the derivation termination condition of the active power standard is not satisfied, the amount of active power variation is reduced and then the step of maximizing the bandwidth to find the LDC setting is repeated.

In the present invention, the second step is defining initial values of variables for obtaining a reactive power standard; After defining the initial values of the variables, maximizing the bandwidth to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth; Comparing the bandwidth among the LDC settings obtained by maximizing the bandwidth with the minimum bandwidth set by the user; According to the result of comparing the bandwidth and the minimum bandwidth, if the minimum bandwidth is large, saving the current settings and adjusting the control frequency and amount of distributed power; And after adjusting the control frequency and amount of distributed power, comparing the amount of change in reactive power and the size of reactive power to derive the reactive power standard and storing the final reactive power standard and LDC when the termination condition is satisfied. do.

In the present invention, the termination condition for deriving the reactive power standard is characterized by comparing whether the amount of reactive power variation is less than a specific value or the reactive power is less than 0.

In the present invention, if the derivation termination condition of the reactive power standard is not satisfied, the amount of reactive power variation is reduced and then the process of maximizing the bandwidth to find the LDC setting is repeated.

In the present invention, the optimal reactive power derived in the third step is characterized in that it is less than the size of the reactive power and is greater than the operating reference voltage for preventing overvoltage.

The voltage management method of the voltage regulator according to one aspect of the present invention is installed in the next-generation distribution management system (Advanced Distribution Management System, ADMS) and can be used by customers in changing system conditions (load/generation, etc.) based on history data of the power system. In order to supply the regulated voltage to all system situations, it satisfies as much as possible, reflects actual situations that may occur by considering the operating speed of each device, and not only minimizes the output of unnecessary reactive power from distributed power sources, but also allows for the division of roles for each device. The voltage can be managed by deriving the setting value of the voltage regulator.

1 is a flowchart illustrating a voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 2 is a flowchart illustrating the process of deriving an active power standard in the voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 3 is a graph showing the maximum/minimum transmission voltage based on active power and LDC in the voltage management method of the voltage adjustment device according to an embodiment of the present invention.
Figure 4 is a flowchart for explaining the process of deriving an active power output standard according to conditions in the voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 5 is a flowchart for explaining the process of deriving a reactive power standard in the voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 6 is a flowchart illustrating the process of deriving a reactive power output standard according to conditions in the voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 7 is a diagram illustrating derivation of required reactive power/voltage for each history in the voltage management method of a voltage regulator according to an embodiment of the present invention.
Figure 8 is a first example diagram for explaining the setting state of distributed power in the voltage management method of the voltage adjustment device according to an embodiment of the present invention.
Figure 9 is a second example diagram for explaining the setting state of distributed power in the voltage management method of the voltage adjustment device according to an embodiment of the present invention.

Hereinafter, the voltage management method of the voltage regulator according to the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or sizes of components shown in the drawing may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are terms defined in consideration of functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, definitions of these terms should be made based on the content throughout this specification.

Although not specifically shown in the drawings of this embodiment below, the voltage management method of the voltage regulator according to this embodiment is installed in the next-generation distribution management system (Advanced Distribution Management System, ADMS) to manage the voltage of the distribution system. A device that performs the device voltage management method may be implemented as a computer (not shown) or a server (not shown) including a CPU (not shown) (or a control unit).

Here, the voltage regulator includes one or more of OLTC (On Load Tap Changer), SVR (Step Voltage Regulator), distributed power, and ESS (Energy Storage System), and the setting value of the voltage regulator is OLTC and SVR. It may include LDC parameters, distributed power, and ESS operating reference voltage values.

Therefore, even if not described in detail for the convenience of explanation below, the entity that executes the voltage management method of the voltage regulator according to this embodiment should be understood as the control unit (not shown).

Figure 1 is a flowchart for explaining a voltage management method of a voltage regulator according to an embodiment of the present invention, and Figure 2 is a flowchart for deriving an active power standard from the voltage management method of a voltage regulator according to an embodiment of the present invention. It is a flowchart for explaining the process, and Figure 3 is a graph showing the maximum/minimum transmission voltage based on active power and LDC in the voltage management method of the voltage adjustment device according to an embodiment of the present invention, and Figure 4 is a graph showing the maximum/minimum transmission voltage of the active power standard and LDC standard of the present invention. It is a flowchart for explaining the process of deriving an active power output standard according to conditions in the voltage management method of a voltage regulator according to an embodiment of the present invention, and Figure 5 is a flowchart of the voltage management method of a voltage regulator according to an embodiment of the present invention. It is a flowchart for explaining the process of deriving the reactive power standard, and Figure 6 is a flowchart for explaining the process for deriving the reactive power output standard according to conditions in the voltage management method of the voltage regulator according to an embodiment of the present invention. , FIG. 7 is a diagram for explaining the derivation of required reactive power/voltage for each history in the voltage management method of the voltage adjustment device according to an embodiment of the present invention, and FIG. It is a first example diagram for explaining the setting state of distributed power in the voltage management method, and Figure 9 is a second example for explaining the setting state of distributed power in the voltage management method of the voltage regulator according to an embodiment of the present invention. It is also a degree.

As shown in FIG. 1, in the voltage management method of the voltage adjustment device according to an embodiment of the present invention, first, the present invention is that the control unit measures the amount of reactive power of the distributed power required to maintain the voltage of the distribution system at the specified voltage as facility capacity. It includes the first step (S10) of deriving based on active power, which is the relative power generation amount.

For example, if the distributed power generation generates more than 50% of the facility capacity and it is impossible to maintain the regulated voltage with OLTC alone, and reactive power control of the distributed power source is required, the active power (Pth) standard is 0.5. As a similar example, if it is difficult to maintain the specified voltage with OLTC alone in all histories subject to review, the active power (Pth) is 0.

The active power (Pth) and OLTC LDC (Line Drop Compensator) settings derived in the first step (S10) are obtained by optimizing the objective function that minimizes voltage violation with the OLTC bandwidth as a constraint.

The active power (Pth) obtained here is not directly applied to the voltage regulator, but is used to calculate the setting and operating voltage input to the voltage regulator.

More specifically, the process of deriving the distributed power active power standard that maintains the specified voltage based on the minimum bandwidth (Vbw_min) of the OLTC, which is a voltage regulator, is described with reference to FIG. 2 as follows.

First, initial values of variables for calculating the active power standard (Pth) are defined (S110).

Here, Pth = 1 means control when the distributed power generation amount is more than 100% of the facility capacity, and Pth = 0 means control when the distributed power generation amount is more than 0% of the facility capacity. It is used for voltage control regardless of power generation. This means that reactive power (Qratio) will be used.

Reactive power (Qratio) refers to the range to be used for voltage control purposes among the usable reactive output ranges for each facility, and if Qratio is 1, it means that all available reactive power will be used, the first step (S10) to derive the active power standard. ), Qratio can be fixed to 1. Additionally, a Qratio of 0.5 means that only 50% of the given range will be used.

del_Pth is a value for adjusting the active power (Pth), Pth_best is the current Pth that satisfies the constraints (standard voltage, minimum OLTC bandwidth), and LDC_best is the value that satisfies the constraints (standard voltage, minimum OLTC bandwidth). This is LDC to date.

After defining the initial values of the variables in step S110, the bandwidth (Vbw) is maximized to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth (S120).

Here, maximizing bandwidth (Vbw) reflects the Pth defined at the time of initial execution and the Pth determined for adjustment of active power, and finds an LDC setting that maintains the OLTC bandwidth at the maximum and the specified voltage while Qratio is fixed at 1. .

Figure 3 is a graph of maximum/minimum transmission voltage based on active power (Pth) and LDC.

At this time, Pth is reflected to find the maximum/minimum transmission voltage to maintain the voltage at all bus bars based on the Pth determined in the previous step.

For example, based on Pth, Pth = 0.5 (Qratio is fixed at 1) means that when power generation exceeds 50% of the facility capacity, this becomes a control means to maintain the grid voltage within an appropriate range. In this way, based on Pth, Once you find the transmission voltage, you can find the OLTC LDC settings to satisfy it.

Here, the reason why you need to find the LDC transmission voltage that satisfies it after finding the transmission voltage based on active power (Pth) is that LDC provides transmission voltage based on one fixed setting, so in all cases, the best (Pth standard transmission) This is because the transmission voltage cannot be provided.

Afterwards, the bandwidth (Vbw_opti) among the LDC settings obtained in step S120 is compared with the user-set minimum bandwidth (Vbw_min) (S130).

Here, the smaller the minimum bandwidth set by the user, the greater the number of OLTC operations, and the lower the control frequency and amount of distributed power. Conversely, as the minimum bandwidth increases, the number of OLTC operations decreases and the control frequency and control amount of distributed power increases.

Therefore, step S130 can compare the bandwidth or the number of operations. When comparing the number of operations, it is possible to check the change in the number of operations of OLTC by comparing the existing LDC settings and the candidate LDC settings.

The history of the system reviewed here (load of withdrawals, etc.) can be secured as input data. For example, the number of possible OLTC operations can be calculated based on one year of load data, and the number of OLTC operations can be calculated using the same history as above based on the candidate LDC settings. At this time, if the user sets the number of operations below 90% of the previous level, only the LDC settings that are 90% or less based on the number of operations can be selected as the target.

As a result of comparing the bandwidth (Vbw_opti) with the minimum bandwidth (Vbw_min) in step S130, if the current OLTC bandwidth is greater than the user setting, the current setting is saved (Pth_best=Pth, LDC_best=LDC), and the control frequency and Reduce the amount (Pth=Pth+del_Pth)(S140).

On the other hand, as a result of comparing the bandwidth (Vbw_opti) with the minimum bandwidth (Vbw_min) in step S130, if the current OLTC bandwidth is smaller than the user setting, the constraint is violated, so the control frequency and amount of distributed power are increased to solve this problem (Pth= Pth-del_Pth)(S150).

After adjusting the control frequency and amount of distributed power in steps S140 and S150, it is compared whether the Pth variation amount (del_Pth) is less than a specific value (0.1) or Pth is less than 0 or more than 1 (S160).

Here, the condition of del_Pth < 0.1 is a case where the difference between the previous step and the result value is small due to repeated calculation, and the end criterion for the variable value can be changed depending on the calculation speed and control policy. The condition of Pth < 0 is a condition in which an appropriate voltage cannot be maintained even if distributed power is controlled to the maximum based on the current OLTC minimum bandwidth standard, and the condition of Pth > 1 is a condition in which an appropriate voltage can be maintained only with OLTC even without control of distributed power.

Therefore, if the condition is not satisfied in step S160, reduce the Pth variation size by 50% and return to step S120 and repeat.

That is, as shown in FIG. 4, the size of the Pth variation is reduced by 50%, then the bandwidth (Vbw_opti) and the minimum bandwidth (Vbw_min) are compared, the above process is repeated, and the control frequency and amount of distributed power are adjusted according to the comparison results. Thus, the active power output standard can be derived.

On the other hand, if the conditions are not satisfied in step S160, the final active power (Pth) standard and LDC are stored and terminated (S180).

The present invention is a reactive power (Qratio) standard for reducing reactive power compared to the maximum output of reactive power that satisfies the active power standard and the minimum bandwidth of the voltage regulator by the control unit after deriving the active power standard in the first step (S10). It includes the second step (S20) of deriving .

In Europe, North America, and Korea, the maximum reactive power output of distributed power sources is set at a power factor of 90%. This means that reactive power output must be possible up to 44% of the apparent power. In the first step (S10), the active power (Pth) standard and OLTC LDC settings are obtained based on the maximum output of reactive power (44% of the apparent power).

For example, if only 50% of reactive power is required compared to the maximum reactive power output, the reactive power (Qratio) is 0.5. The fixed settings are the active power (Pth) standard and the OLTC bandwidth, and the reactive power (Qratio) and OLTC LDC to be found are designed with the active power standard and OLTC LDC settings as design variables, and voltage violations are determined with the OLTC bandwidth and active power as constraints. It is obtained by optimizing the objective function to be minimized.

The reactive power obtained here is not directly applied to the voltage regulator, but is used to calculate the setting and operating voltage input to the voltage regulator.

More specifically, the process of deriving the minimum bandwidth (Vbw_min) of the OLTC, which is a voltage regulator, and the reactive power standard that satisfies the active power standard will be described with reference to FIG. 5 as follows.

First, define the initial values of variables to obtain the reactive power standard (Qratio) (S210).

Qratio=0 means that 0% of the available reactive power will be used, and Qratio=1 means that 100% of the available reactive power will be used.

Here, the case where Qratio=1 is satisfied is fixed and derived in the first step (S10), so the case where Qratio is always 1 or less will be described.

del_Qratio=0.5 sets the initial value of the change value when adjusting the Qratio size to 0.5, and the initial OLTC LDC setting uses the LDC value obtained when deriving the active power standard.

After defining the initial values of the variables in step S210, the bandwidth (Vbw) is maximized to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth (S220).

Here, maximizing the bandwidth (Vbw) reflects the Qratio defined at the time of initial execution and the Qratio determined for adjustment of reactive power, maintaining the OLTC bandwidth at the maximum while Pth is fixed to the value derived in the first step, and the specified voltage is maintained at the maximum. Find a maintainable LDC setting.

At this time, the Qratio is reflected to find the maximum/minimum transmission voltage to maintain the voltage at all busbars based on the Qratio determined in the previous step (by controlling reactive power).

Find the transmission voltage based on the Qratio obtained in this way, and find the OLTC LDC setting that satisfies this.

Here, the reason why you need to find the LDC transmission voltage that satisfies it after finding the Qratio standard transmission voltage is because LDC provides transmission voltage based on one fixed setting, the best (Qratio standard transmission voltage) transmission voltage is available in all cases. This is because it cannot be provided.

The bandwidth (Vbw_opti) among the LDC settings obtained in step S220 is compared with the minimum bandwidth (Vbw_min) set by the user (S230).

Here, as the bandwidth becomes smaller, the number of OLTC operations increases and the control frequency and amount of distributed power decreases. Conversely, as the bandwidth increases, the number of OLTC operations decreases and the control frequency and amount of distributed power increases.

Therefore, step S230 can compare the bandwidth or the number of operations. When comparing the number of operation strokes, it is possible to check the change in the number of operations of OLTC by comparing the existing LDC setting and the candidate LDC setting.

In step S230, as a result of comparing the bandwidth (Vbw_opti) with the minimum bandwidth (Vbw_min), if the current OLTC bandwidth is greater than the user setting, the current setting is saved (Qratio_best=Qratio, LDC_best=LDC), and the control frequency and amount of distributed power Reduce (Qratio=Qratio-del_Qratio) (S240).

On the other hand, if the current OLTC bandwidth is smaller than the user setting as a result of comparing the bandwidth (Vbw_opti) with the minimum bandwidth (Vbw_min) in step S230, it is a constraint violation. To solve this, increase the control frequency and amount of distributed power (Qratio =Qratio+del_Qratio)(S250).

After adjusting the control frequency and amount of distributed power in steps S240 and S250, it is compared to see whether the Qratio variation is less than a specific value (0.1) or Qratio is less than 0 (S260).

Here, the condition of del_Qratio<0.1 is a case where the difference between the previous step and the result value is small due to repeated calculation, and the end criterion for the variable value can be changed depending on the calculation speed and control policy. The condition of Qratio<0 is a condition in which an appropriate voltage can be maintained using only OLTC without reactive power control.

Therefore, if the condition is not satisfied in step S260, reduce the size of the Qratio change by 50% and return to step S220 and repeat.

That is, as shown in FIG. 6, the size of the Qratio variation is reduced by 50%, then the bandwidth (Vbw_opti) and the minimum bandwidth (Vbw_min) are compared, the above process is repeated, and the control frequency and amount of distributed power are adjusted according to the comparison results. Thus, the reactive power output standard can be derived.

On the other hand, if the conditions are not satisfied in step S260, the final reactive power (Qratio) standard and LDC are stored and terminated (S280).

The present invention includes a third step (S30) in which the control unit derives the optimal reactive power value required for each history based on the reactive power after deriving the reactive power standard in the second step (S20).

Reactive power (Qratio) is a value that is applied equally to all histories. For example, in 99% of cases, there is a solution where Qratio is 0.1, but in only 1% of cases where it is 0.5 or more, Qratio is 0.5. That is, the size of the reactive power for each individual history is always less than or equal to the size of the reactive power obtained in the second step (S20).

In the third step (S30), the minimum reactive power and connection point voltage of the distributed power required for each history are calculated and stored based on the OLTC LDC settings obtained in the second step (S20).

By obtaining the active power (Pth) standard and the reactive power (Qratio) standard in the first step (S10) and the second step (S20), the reactive power that is commonly satisfied in all histories can be found. In other words, the minimum reactive power size required for each individual history is always less than the commonly applied reactive power (Qratio) size.

As shown in FIG. 7, when explaining a system with three distributed power sources based on three histories, there are three distributed power sources in the system and are connected to positions 1, 2, and 3 in order of distance, and each distributed power source The meaning of the numbers above is as follows.

is the voltage at each point (distributed power connection point) when applying the Pth and Qratio derived in the first step (S10) and the second step (S20), and ① is the reactive power required to comply with the regulated voltage in history 1. When applied, it is the voltage at each point, and ② and ③ mean the voltage at each point when reactive power is applied in records 2 and 3.

That is, the minimum reactive power required for each history is less than or equal to the reactive power size derived from the existing second stage (S20), which is applied equally to all histories, and the operating reference voltage for overvoltage prevention is greater than that of the existing second stage (S20).

The present invention calculates the optimal reactive power and connection point voltage for each history in the third step (S30), and then performs a fourth step (S40) in which the control unit derives the setting value of the voltage adjustment device based on the optimal reactive power and connection point voltage. Includes.

In order to derive the setting value of the voltage regulator based on the optimal reactive power and connection point voltage without causing a voltage violation in any history, the worst case situation must be considered.

For example, distributed power supply number 1 shown in FIG. 7 must operate based on history number 1 so that overvoltage problems do not occur even in history numbers 2 and 3. If it operates based on history number 2, overvoltage occurs in history number 1. Likewise, in the case of distributed power sources 2 and 3, they must be operated based on the history of number 2 to avoid overvoltage problems.

As shown in Figure 8, when explaining the DER-AVM (distributed power active voltage control device) used by Korea Electric Power Corporation as an example, assuming that there are 6 histories in a single distributed power source, histories 1, 2, and 3 Absorbs reactive power to prevent overvoltage. Among these, hysteresis number 3 begins to absorb reactive power at the lowest voltage.

Therefore, to prevent overvoltage in all cases, set the voltage of history 3 as the upper voltage limit of the DER-AVM. And, using a similar principle, the lower voltage limit is set for voltage 4 to prevent low voltage.

In addition, as shown in Figure 9, it is an example graph of the Q(V) curve setting used for reactive power control in distributed power and ESS.

As shown here, the reactive power output amount for each history of a specific distributed power source (maximum ground reactive power: Qmin, maximum leading reactive power: Qmax) and the voltage at the connection point at that point can be expressed.

In Figure 9, the upper part is the part that supplies leading reactive power to increase the voltage, and among these, voltage 1 is the highest. In other words, number 1 is the leading reactive power output reference point, and V1 and V2 are determined according to the slope of the line passing through this point. At this time, the steeper the slope, the more distributed power control amount increases even with the same voltage change.

For example, the black solid line passing through point 1 supplies more reactive power than the red dotted line for the same voltage change.

In addition, ground reactive power consumption for voltage drop is determined in a similar manner as above, with the lowest voltage, number 2, being the reference point for ground reactive power output.

By applying the settings of the voltage regulators such as OLTC, SVR, distributed power, and ESS derived in this way, voltage management of the distribution system can be performed.

Here, the setting value of the voltage regulator may include LDC parameters of OLTC and SVR, and operating reference voltage values of distributed power and ESS.

As described above, according to the voltage management method of the voltage regulator according to the embodiment of the present invention, the system situation (system situation) is installed in the next-generation distribution management system (Advanced Distribution Management System, ADMS) and changes based on the history data of the power system. load/generation, etc.) to satisfy all system conditions as much as possible in order to supply the regulated voltage to customers, reflect actual situations that may occur by considering the operation speed of each device, and minimize the output of unnecessary reactive power from distributed power sources. In addition, the voltage can be managed by deriving the setting value of the voltage regulator to enable division of roles for each device.

Implementations described herein may be implemented, for example, as a method or process, device, software program, data stream, or signal. Although discussed only in the context of a single form of implementation (eg, only as a method), implementations of the features discussed may also be implemented in other forms (eg, devices or programs). The device may be implemented with appropriate hardware, software, firmware, etc. The method may be implemented in a device such as a processor, which generally refers to a processing device that includes a computer, microprocessor, integrated circuit, or programmable logic device. Processors also include communication devices such as computers, cell phones, portable/personal digital assistants (“PDAs”) and other devices that facilitate communication of information between end-users.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those skilled in the art will recognize that various modifications and other equivalent embodiments are possible therefrom. You will understand.

Therefore, the true technical protection scope of the present invention should be determined by the claims below.

Claims (11)

A first step in which the control unit derives the amount of reactive power of the distributed power source required to maintain the voltage of the distribution system at the specified voltage based on the active power, which is the amount of power generation compared to the facility capacity;
A second step in which the control unit derives a reactive power standard for reducing reactive power compared to the maximum output of reactive power that satisfies the active power standard and the minimum bandwidth of the voltage regulator;
A third step in which the control unit derives the optimal reactive power value required for each history based on the reactive power standard; and
A fourth step in which the control unit derives a setting value of the voltage adjustment device based on the optimal reactive power and the connection point voltage,
The first step is,
defining initial values of variables for obtaining the active power standard;
After defining the initial values of the variables, maximizing the bandwidth to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth;
Comparing the bandwidth among the LDC settings obtained by maximizing the bandwidth with the minimum bandwidth set by the user;
Saving the current settings and adjusting the control frequency and amount of distributed power when the minimum bandwidth is large according to the result of comparing the bandwidth and the minimum bandwidth; and
After adjusting the control frequency and amount of the distributed power, comparing the amount of change in active power and the size of active power, and storing the final active power standard and LDC when the derivation end condition of the active power standard is satisfied,
The derivation termination condition of the active power standard is a voltage management method of a voltage regulator, characterized in that it compares whether the amount of active power variation is less than a specific value or the active power is less than 0 or more than 1.
The voltage regulator according to claim 1, wherein the voltage regulator includes one or more of an On Load Tap Changer (OLTC), a Step Voltage Regulator (SVR), a distributed power source, and an Energy Storage System (ESS). Voltage management method.
The voltage management method of claim 2, wherein the setting value of the voltage regulator includes LDC parameters of OLTC and SVR, and operating reference voltage values of distributed power and ESS.
The voltage management of the voltage regulator according to claim 1, wherein in the first step, the active power and the OLTC LDC (Line Drop Compensator) are optimized and obtained through an objective function that minimizes voltage violation with the OLTC bandwidth as a constraint. method.
delete delete The voltage of the voltage regulator according to claim 1, wherein if the derivation termination condition of the active power standard is not satisfied, the amount of active power variation is reduced and then the step of maximizing the bandwidth to find the LDC setting is repeated. How to manage.
The method of claim 1, wherein the second step is:
defining initial values of variables for obtaining the reactive power standard;
After defining the initial values of the variables, maximizing the bandwidth to find an LDC setting that can maintain the specified voltage while maximizing the OLTC bandwidth;
Comparing the bandwidth among the LDC settings obtained by maximizing the bandwidth with the minimum bandwidth set by the user;
Saving the current settings and adjusting the control frequency and amount of distributed power when the minimum bandwidth is large according to the result of comparing the bandwidth and the minimum bandwidth; and
After adjusting the control frequency and amount of the distributed power, comparing the amount of change in reactive power and the size of the reactive power, and storing the final reactive power standard and LDC when the derivation end condition of the reactive power standard is satisfied. How to manage the voltage of a voltage regulator.
The voltage management method of claim 8, wherein the termination condition for deriving the reactive power standard compares whether the amount of change in reactive power is less than a specific value or the reactive power is less than 0.
The voltage of the voltage regulator according to claim 8, wherein if the derivation termination condition of the reactive power standard is not satisfied, the amount of reactive power change is reduced and then the step of maximizing the bandwidth to find the LDC setting is repeated. How to manage.
The voltage management method of a voltage regulator according to claim 1, wherein the optimal reactive power derived in the third step is less than the size of the reactive power and greater than the operating reference voltage for preventing overvoltage.

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