KR20150037357A - System for controlling flexible ac transmission system - Google Patents

Abstract

The present invention relates to a device for controlling a flexible AC transmission system (FACTS) which comprises: an input unit to receive power system data and a contingency list including a plurality of contingencies; a calculation unit to calculate a reactive power supply amount for adjusting the supply and demand of high voltage direct current (HVDC) reactive power by using the power system data, to determine the operation mode of an FACTS device based on the calculated reactive power supply amount, to calculate reactive power reserves for all the contingencies included in the contingency list, and to determine the optimal operation point of the FACTS device based on the calculation result; and a control unit to control the FACTS device with the determined optimal operation point of the FACTS device.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible transmission system,

The present invention relates to an apparatus for operating a flexible transmission system, and more particularly, to an apparatus for operating a flexible transmission system capable of actively controlling the supply and demand of reactive power for facilities requiring adjustment of supply and demand of reactive power according to transmission capacity variation such as HVDC (High Voltage Direct Current) In addition, the present invention relates to an apparatus for operating a flexible transmission system capable of securing reactive power reserve in case of an emergency.

In general, Flexible AC Transmission Systems (FACTS) devices use high-capacity power electronic technology to precisely control the system parameters of power tide, grid voltage and system stability at high speed, thereby improving system stability, power transmission capacity, Can be improved.

Of the FACTS devices, the parallel FACTS device is a device for rapidly controlling a capacitor or a reactor to control reactive power and voltage.

Accordingly, if the FACTS device or a plurality of FACTS devices are appropriately controlled according to the situation of the nearby power system, it is possible to improve the voltage stability of the power system through the free power supply and to secure the reactive power reserve It can also be used as pure power (momentary reactive) power source.

As shown in FIG. 1, the parallel type FACTS device can operate in inductive or capacitive mode. If the FACTS device operates in an inductive mode in preparation for an emergency, The reactive power supply amount that can be supplied to the system can have an increased effect.

On the other hand, the HVDC system converts AC power generated from an AC power source to DC power using a converter, transfers it to a long-distance processing line or cable, and then converts the DC power to AC power using an inverter to transmit it to a customer .

In the HVDC system, due to the reactance component of the converter, a reactive power loss occurs during active power transmission, and the reactive power Q corresponding to about 70% of the active power P to be transmitted must be compensated . Also, when the HVDC operating in the constant frequency mode is connected, the HVDC compensates for the changed active power when the active power changes in the power system. And the reactive power compensation capacity (Q / P? 0.7) according to the active power compensation of the HVDC is further increased.

Typically, the input and opening of the filter and the parallel capacitor increase the reactive power supply of the HVDC or reduce the reactive power supply. However, since the input and the opening of the filter and the parallel capacitor are performed in a stepwise manner (discontinuous), there is a problem that reactive power supply and reduction can not be precisely controlled.

Background Art [0002] The background art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 10-1307-0037224 (published on Mar. 14, 2007,

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to actively regulate the supply and demand of reactive power for facilities requiring adjustment of supply and demand of reactive power according to transmission capacity variation such as HVDC (High Voltage Direct Current) And to provide a device for operating a flexible transmission system capable of securing reactive power reserve in case of emergency.

An apparatus for operating a flexible transmission system according to an aspect of the present invention includes an input unit for receiving a list of assumed incidents including power system data and a plurality of assumed incidents; Calculates a reactive power supply amount for regulating the supply of high voltage direct current (HVDC) reactive power to the power system data, determines an operation mode of the FACTS (Flexible AC Transmission Systems) based on the calculated reactive power supply amount, Calculating a reactive power reserve for an assumed incident included in the assumed incident list, and determining an optimum operating point of the FACTS device based on the calculated result; And a control unit for controlling the FACTS device at an optimal operating point of the determined FACTS device.

In the present invention, the arithmetic unit determines the presence or absence of data related to the HVDC in the power system data, calculates the reactive power (Q) compensation supply amount due to the HVDC active power transmission when there is data related to the HVDC, And the reactive power amount to be compensated in accordance with the input and the opening of the capacitor bank and the filter are calculated.

In the present invention, the operation unit compares the capacity of the charged or unloaded capacitor bank and the filter with the reactive power (Q) compensation supply amount due to the HVDC active power transmission, and when the capacitor bank and the filter are overloaded, The operation point is calculated so as to operate in an inductive mode and the operating point is calculated so that the FACTS device can be operated in a capacitive mode when the input of the capacitor bank and the filter is small .

In the present invention, the operation unit may further calculate a reactive power margin obtainable by the FACTS device according to the operation mode of the FACTS device, further receive an assumed incident list on the electric power system data input from the input unit, And the first assumed accident, which is the accident that has the greatest influence on the power system, is applied.

In the present invention, the arithmetic unit calculates the reactive power increment and the reactive power reserve according to the active power increment and the HVDC active power increment that the HVDC must further transfer by applying the power system data and the first assumed accident .

In the present invention, the arithmetic operation unit compares the reactive power margin secured by the FACTS device with the reactive power increase value and the reactive power reserve value of the HVDC to be input to the power system when an assumed incident occurs, The operating point of the FACTS device is recalculated to further control the FACTS device in the inductive mode when the reactive power margin is smaller.

In the present invention, the arithmetic operation unit compares the reactive power margin secured by the FACTS device with the reactive power increase value and the reactive power reserve value of the HVDC to be input to the power system when an assumed incident occurs, The calculated operating point is maintained without changing the operating point of the FACTS device when the reactive power margin is larger or equal to the operating point.

)에 따라, FACTS 기기별로 운전점을 계산하는 것을 특징으로 한다.In the present invention, when a plurality of FACTS apparatuses are installed in the power system, the arithmetic operation unit calculates the sensitivity of the bus lines to which the respective FACTS apparatuses are connected

), The operation point is calculated for each FACTS device.

In the present invention, in order to control the supply and demand of HVDC reactive power and reserve the reactive power reserve, the operation unit finally determines the operation point for each FACTS device, and transmits the final operating point of the determined FACTS device to the corresponding FACTS And outputting to the device for control.

In the present invention, in the case where there is no data related to HVDC determination and data relating to HVDC in the power system data, the calculation unit further receives a list of assumed incidents to the power system data input from the input unit, And the first assumed accident, which is an affecting accident, is applied.

In the present invention, the arithmetic unit calculates the reactive power reserve to be applied to the power system by applying the power system data and the first assumed accident, and also calculates the reactive power reserve value and the power And compares the reactive power margin secured in the system.

In the present invention, the arithmetic operation unit compares the reactive power reserve to be supplied to the power system when an assumed incident occurs and the reactive power margin secured in the power system that does not take into consideration the assumed incident, and the reactive power reserve If the FACTS device or the plurality of FACTS devices is further controlled in the direction of the inductive mode, the operating point of the FACTS device is recalculated and the reactive power reserve (Qrev, Vref) of the FACTS device is recalculated in order to minimize the effective power transmission loss when the calculated reactive power margin is smaller than or equal to the secured reactive power margin.

The present invention is not only capable of ensuring sufficient reactive power reserve for an FACTS device (or FACTS device) in case of an accident or a situation that may occur in a power system, but also for controlling HVDC reactive power supply (or discontinuity improvement) Let's solve it together. Further, the present invention not only enables effective control of a plurality of HVDC and parallel FACTS devices, but also can be applied to control of FACTS devices as the development and expansion of a smart grid of a wind power generation complex progresses.

1 is a conceptual diagram of operation of a general parallel type FACTS device.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a FACTS system, and more particularly,
FIG. 3 is an exemplary diagram schematically showing the internal configuration of the FACTS operating device in FIG. 2; FIG.
4 is a diagram illustrating an operation concept of a parallel FACTS device according to an embodiment of the present invention.
5 is a flowchart illustrating a method of calculating and controlling a FACTS operating point in a FACTS operating apparatus according to an embodiment of the present invention.
6 is an exemplary diagram for explaining a basic concept of an FACTS system for performing cooperative control between an HVDC system and an FACTS device by applying a FACTS operating device according to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an apparatus for operating a flexible transmission system according to the present invention will be described with reference to the accompanying drawings.

In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

FIG. 2 is a diagram schematically illustrating a configuration of an FACTS system to which a FACTS operating apparatus according to an embodiment of the present invention is applied.

2, the FACTS system to which the FACTS operating apparatus according to an embodiment of the present invention is applied includes a FACTS controller 110, a power system information collection system 120, and a FACTS operating apparatus 130. As shown in FIG.

The FACTS controller 110 controls the corresponding FACTS device with the optimum operating point of the FACTS (Qrev: amount of reactive power to be secured, operation voltage of FACTS for Vref: Qrev) received through the FACTS operating device 130 .

The power system information collection system 120 collects and stores all the data of the power system in real time.

The power system information collection system 120 inputs the collected power system data to the FACTS operating device 130.

The power system data collected through the power system information collection system 120 is transmitted to the FACTS operating device 130 through an algorithm for controlling the reactive power supply and the reserve of reactive power so that the optimal operating point (Qrev, Vref) of the FACTS Used to calculate. The calculated optimal operating point (Qrev, Vref) of the FACTS is provided to the FACTS controller (110).

The FACTS controller 110 can control the reactive power supply and demand of the power system by operating the FACTS at the optimum operating point Qrev and Vref and improve the reactive power reserve (securing the reactive power reserve in preparation for the assumed accident). All information related to the power system for the FACTS controlled as described above is fed back to the information collection system 120 to be used for the calculation of the reactive power supply control and the reserve for the reactive power reserve.

The above process is repeatedly performed to optimally operate the FACTS device (or a plurality of FACTS devices) so as to optimize the reactive power reserve according to the active power supply of the HVDC and the reactive power reserve for the assumed incident .

The FACTS operating device 130 receives the power system data and the assumed incident list from the power system information collecting system 120 and calculates the FACTS through the calculation process for the HVDC reactive power supply and demand adjustment and the reactive power reserve And outputs the optimum operating point to the FACTS controller 110.

FIG. 3 is a diagram schematically illustrating an internal configuration of the FACTS operating device in FIG. 2, and FIG. 4 is an exemplary diagram illustrating a driving concept of a parallel FACTS device according to an embodiment of the present invention.

4 (a) and 4 (b), the points (a) and (a ') represent the initial operating points of the FACTS apparatus for regulating the supply and demand of HVDC reactive power, and the points (b) and (C) and (c ') indicate the reactive power (Q) margin secured by the FACTS equipment for the point of operation (a) or (a' (D) represents the reactive power reserve (Qrev), and the points (d ') represent the FACTS equipment operation points for regulating the supply and demand of HVDC reactive power and securing the reactive power reserve (Qrev) against the assumed accident.

Hereinafter, the operation of the FACTS operating apparatus will be described with reference to FIG. 3 and FIG.

3, the FACTS operating device 130 includes an input unit 131, an operation unit 132, and a control unit 133.

The input unit 131 receives power system data from the power system information collecting system 120 described with reference to FIG. Also, the input unit 131 receives a list of assumed incidents for a plurality of assumed incidents that may occur in the power system.

The operation unit 132 calculates the optimal operating point of the FACTS device (or each FACTS device) by applying the first assumed accident (the accident that affects the system in the event of an accident) and the input power system data do.

For example, referring to FIG. 4 (a), the FACTS device determines an initial operating point at the inductive mode (a) in order to control the supply and demand of reactive power of the HVDC by using the current power system data and the HVDC effective power transmission amount .

The reactive power (Q) margin secured by the FACTS device to the point of operation (a) becomes the area (b), and when the assumed accident occurs, the reactive power of the area (b) It has the effect of being able to. After the point (a), which is the initial operating point of the FACTS apparatus, is determined, the reactive power reserve (Qrev) required in the power system is calculated using the first assumed probability.

If the reactive power reserve Qrev required by the power system is greater than the reactive power (Q) margin secured at the point (a), which is the initial operating point of the FACTS device, in preparation for the first assumed accident, The operating point is moved to point (d).

For example, referring to (B) of FIG. 4, the FACTS device determines the initial operating point at the point of the capacitive mode (a ') in order to control the supply and demand of the reactive power of the HVDC by using the current power system data and the HVDC effective power transmission quantity. do.

The reactive power (Q) margin secured by the FACTS device to the point of operation (a ') becomes (b'), and when an assumed accident occurs, the reactive power of (b ' And the like. After the point (a '), which is the initial operating point of the FACTS apparatus, is determined, the reactive power reserve (Qrev) required in the power system is calculated using the first assumed probability.

If the reactive power reserve Qrev required in the power system is greater than the reactive power (Q) margin secured at the point (a '), which is the initial operating point of the FACTS device, against the first assumed accident, To the point (d ').

The operation unit 132 derives a new operating point of the FACTS device (or a plurality of FACTS devices) in order to regulate the supply and demand of the HVDC reactive power and to secure the reactive power reserve (Qrev).

For example, in contrast to the first assumed accident, the amount of reactive power reserve (Qrev) required in the power system is smaller than the reactive power (Q) margin secured at the point (a) or (a '), which is the initial operating point of the FACTS device , The operating point of the FACTS equipment will maintain the initial operating point (a) or (a ').

As described above, the operation unit 132 outputs the optimal operating point of the FACTS device to the control unit 133 when the optimal operating point of the FACTS equipment is derived by applying the assumed incident to the power system data.

Accordingly, the control unit 133 controls the FACTS device by using the optimal operating point of the FACTS device derived through the operation unit 132.

FIG. 5 is a flowchart illustrating a method of calculating and controlling an FACTS operating point in a FACTS operating apparatus according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating a method of calculating and controlling a FACTS operating point according to an embodiment of the present invention. And an FACTS system that performs cooperative control with the FACTS device.

Hereinafter, the operation of the FACTS operating device 130 will be described with reference to FIGS. 5 and 6. FIG.

The FACTS operating device 130 receives power system data through the power system information collection system 120 (S310).

The power system information collection system 120 collects all data of the power system in real time, as described in FIG. Accordingly, the FACTS operating device 130 receives necessary power system data through the power system information collection system 120 to calculate an optimal operating point of the FACTS device. Also, the FACTS operating device 130 receives a list of assumed incidents including various assumed incidents of the power system.

The FACTS operating device 130 determines whether there is data related to the HVDC in the input power system data (S315).

When there is data related to the HVDC (YES in S320), the HVDC receives the active power transmission amount (or the transmission capacity) according to the determination, and calculates the reactive power (Q) compensation supply amount due to the HVDC active power transmission (S320).

In general, an HVDC system (not shown) inputs a capacitor bank and a filter 220 installed in the HVDC system 210 to compensate for reactive power according to active power transmission (S325). The input and control of the capacitor bank and the filter 220 are performed in the HVDC system 210 and the amount of input may be different depending on the manufacturer of the HVDC. However, since the capacitor bank (the capacitor bank) and the filter 220 are opened and closed in a stepped manner (discontinuous), reactive power supply and reduction can not be precisely controlled.

The FACTS operating device 130 compares the capacity of the capacitor bank and the filter 220 charged (or opened) in step S325 with the reactive power supply amount Q compensated for the HVDC active power transmission (S330 ).

If the inductive compensation is required due to overloading (or opening) of the capacitor bank and the filter 220 (in the example of S330), the FACTS operating device 130 may be a FACTS device The operation point Vref is calculated (S335) so that the FACTS apparatuses of the FACTS apparatuses can operate in an inductive mode.

However, if the capacities of the capacitor bank and the filter 220 are small and capacitive compensation is required (NO in S330), the FACTS operating unit 130 may operate the FACTS device (or a plurality of FACTS devices The operation point Vref is calculated so that the operation mode can be operated in the capacitive mode (S340).

Further, the reactive power (Q) margin obtainable by the FACTS device is further calculated according to the operation point (Vref) of the FACTS device calculated in steps S335 and S340.

Further, the FACTS operating device 130 further receives a main assumption list on the received power system data, and applies the first assumed assumption (S345).

On the other hand, when the HVDC operating in the constant frequency mode is connected, the HVDC compensates for the changed active power when an assumed incident occurs in the power system. And the reactive power compensation capacity (Q / P? 0.7) due to the active power compensation of the HVDC is further increased.

In operation S350, the FACTS operating unit 130 calculates the increment of the active power P to which the HVDC is to be additionally transmitted by applying the input power system data and the first assumption.

The FACTS operating device 130 calculates the reactive power increment and the reactive power reserve Qrev according to the active power P increment of the HVDC calculated in step S350 in operation S355.

The FACTS operating device 130 compares the reactive power (Q) margin calculated in step S335 or step S340 with the reactive power increase and reactive power reserve (Qrev) values of the HVDC to be input to the power system in the event of an assumed occurrence (S360).

If the sum of the reactive power (reactive power reserve, Qrev) to be added to the power system is greater than the reactive power (Q) margin calculated in step S335 or S340 (YES in step S360) The FACTS operating device 130 recalculates the operating point (Qrev, Vref) of the FACTS device so that the FACTS device (or a plurality of FACTS devices) can additionally control in the direction of the inductive mode (S365).

For example, referring to FIG. 4, when the operation point of the FACTS device calculated in step S335 or step S340 is the point (a) or (a '), the operation point of the FACTS device d) or (d ').

However, if the sum of reactive power (reactive power reserve, Qrev) to be added to the power system is less than or equal to the reactive power (Q) margin calculated in step S335 or step S340 (NO in S360) The FACTS operating device 130 does not change the operating point of the FACTS device but maintains the operating point Qrev and Vref calculated in step S335 or S340 as it is in step S370.

, 무효전력 증가에 따른 모선의 전압 변동률)에 따라 추가로 확보되어야하는 총 무효전력(또는 상기 S335 단계 또는 S340 단계에서 계산된 무효전력(Q) 마진)을 각각 FACTS 기기별로 배분, 운전점을 계산한다(S370). In step S370, when a plurality of FACTS devices are installed in the power system, the FACTS operating device 130 determines the sensitivity of the buses to which the respective FACTS devices are connected

, The total reactive power (or the reactive power (Q) margin calculated in step S335 or S340), which should be additionally ensured according to the reactive power increase, is distributed to each FACTS device, and the operation point is calculated (S370).

)값은 상이할 수 있으며, 계통 운영자에 따라 허용될 수 있는 전압 마진 또한 상이할 수 있으므로 이에 대한 별도의 세부적인 설명은 생략한다.At this time, depending on the scale of the power system and the voltage level of the bus line to which the FACTS is connected,

) Values may be different, and the voltage margin that can be tolerated by the grid operator may also be different, so that a detailed description thereof will be omitted.

The FACTS operating device 130 finally determines the operation point (Qrev, Vref) for each FACTS device in order to regulate the supply and demand of HVDC reactive power and secure the reactive power reserve (Qrev) (S375).

On the other hand, an ancillary equipment, an on-line tap changer (OLTC), etc., which can be added and opened as the operation point of the FACTS equipment is finally determined as described above, is installed in the substation and is connected to the capacitor bank of the HVDC and the filter 220 ) Does not change.

The FACTS operating device 130 outputs the final (or optimal) operating point of the derived FACTS device to the FACTS controller 110. Then, the FACTS controller 110 transmits the corresponding FACTS device to the FACTS operating device 130 using the optimum operating point of the FACTS (Qrev: the amount of reactive power to be secured, the operating voltage of the FACTS for Vref: Qrev) received through the FACTS operating device 130 (S380).

In step S315, the FACTS operating unit 130 determines whether there is data related to the HVDC in the received power system data. If there is no data related to the HVDC (NO in S315), the FACTS operating device 130 proceeds directly to step S345. In step S345, the FACTS operating device 130 further receives a main assumption list on the input power system data, and applies the first assumption (S345).

The FACTS operating device 130 calculates a reactive power reserve (Qrev) value to be applied to the power system according to the occurrence of the first assumed event (S385).

The FACTS operating device 130 compares the reactive power reserve Qrev calculated in step S385 with the reactive power Q margin obtained in the power system not considering the assumed incident in step S390.

If the sum of the reactive power to be supplied to the power system (reactive power reserve, Qrev) is greater than the existing reactive power (Q) margin (YES in S390), the FACTS operating device 130 The operation point (Qrev, Vref) of the FACTS device is calculated so that the FACTS device (or a plurality of FACTS devices) can further control in the direction of the inductive mode (S395).

After the step S395, the steps S370 to S380 are sequentially performed.

However, if the total sum of the reactive power (reactive power reserve, Qrev) to be input to the power system is smaller than or equal to the previously established reactive power (Q) margin (NO in S390), the FACTS operating device 130 changes the operation point (Qrev, Vref) of the FACTS device to minimize the active power transmission loss (S400).

After the step S400, the steps S370 to S380 are sequentially performed.

In this case, the calculation algorithm for minimizing the active power transmission loss may be a general algorithm used for the power system analysis or a separately developed algorithm. In addition to the algorithm for minimizing the effective power transmission loss, a separate algorithm may be applied for the system operator .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, I will understand the point. Accordingly, the technical scope of the present invention should be defined by the following claims.

110: FACTS controller 120: Power system information collection system
130: FACTS operating unit 131: Input unit
132: operation unit 133:
210: HVDC system 220: capacitor bank and filter

Claims (12)

An input unit for receiving power system data and an assumed incident list including a plurality of assumed events;
Calculates a reactive power supply amount for regulating the supply of high voltage direct current (HVDC) reactive power to the power system data, determines an operation mode of the FACTS (Flexible AC Transmission Systems) based on the calculated reactive power supply amount, Calculating a reactive power reserve for an assumed incident included in the assumed incident list, and determining an optimum operating point of the FACTS device based on the calculated result; And
And a control unit for controlling the FACTS equipment with an optimal operating point of the determined FACTS equipment. The apparatus according to claim 1,
If there is data related to the HVDC in the power system data, it is determined that there is data related to the HVDC, and the reactive power (Q) compensating supply amount due to the HVDC active power transmission is calculated, and the capacity of the capacitor bank and the filter And calculates an amount of reactive power compensated by the input and the opening. The image processing apparatus according to claim 2,
It is possible to compare the capacity of the charged or opened capacitor bank and the filter with the reactive power supply amount due to the HVDC active power transmission and to operate the FACTS device in the inductive mode when the capacitor bank and the filter are overloaded. Wherein the operating point is calculated so that the FACTS device can be operated in a capacitive mode when the input of the capacitor bank and the filter is small. The image processing apparatus according to claim 3,
In addition to calculating the reactive power margin that can be secured by the FACTS device according to the operation mode of the FACTS device and further receiving a list of assumed events in the power system data input from the input unit, And a second assumption of the first transmission system is applied to the first transmission system. 5. The apparatus according to claim 4,
Power system data and the first assumption are applied to calculate a reactive power increase and a reactive power reserve according to an active power increment and an HVDC active power increment which the HVDC must additionally transmit. 5. The apparatus according to claim 4,
The reactive power margin that can be secured by the FACTS equipment and the reactive power increase and the reactive power reserve value of the HVDC which are to be input to the power system in case of an assumed incident are compared. If the reactive power margin that can be secured by the FACTS apparatus is smaller Wherein the operating point of the FACTS device is recalculated to further control the FACTS device in the inductive mode direction. 5. The apparatus according to claim 4,
The reactive power margin that can be secured by the FACTS equipment and the reactive power increase and the reactive power reserve value of the HVDC that should be input to the power system in case of an assumed incident are compared and the reactive power margin obtainable by the FACTS apparatus is equal to or greater than Wherein the operating point of the FACTS device is maintained without changing the operating point of the FACTS device. 8. The image processing apparatus according to claim 6 or 7,
When a number of FACTS devices are installed in the power system, the sensitivity of the buses to which each FACTS device is connected (

), Wherein the operating point is calculated for each FACTS device. 9. The image processing apparatus according to claim 8,
The operation point is finally determined for each FACTS device and the final operating point of the determined FACTS device is output to the corresponding FACTS device through the control section for controlling the HVDC reactive power supply and the reactive power reserve, A device for operating a flexible transmission system. The apparatus according to claim 1,
If there is no data related to HVDC in the power system data and there is no data related to HVDC, a list of assumed incidents is additionally input to the power system data input from the input unit, and the first assumed incident Is applied to the power transmission system. 11. The image processing apparatus according to claim 10,
The reactive power reserve to be applied to the power system is calculated by applying the power system data and the first assumed accident and the calculated reactive power reserve value is compared with the reactive power margin secured in the power system not considering the assumed accident And the operation of the flexible transmission system. 12. The image processing apparatus according to claim 11,
Wherein the control unit compares the reactive power reserve to be supplied to the power system when an assumed incident occurs and the reactive power margin secured in the power system that does not take the assumed incident into account, and when the reactive power reserve is greater than the reactive power reserve, The operation point of the FACTS device is recalculated so that the FACTS device or the plurality of FACTS devices can further control in the direction of the inductive mode, and the reactive power margin And the operating point (Qrev, Vref) of the FACTS device is recalculated in order to minimize the effective power transmission loss.

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