KR102817936B1 - An apparatus and a method of analyzing power system based on automatic identification of overhead line and underground line - Google Patents

Abstract

According to one embodiment of the present invention, a power system analysis device includes an underground and overhead line discrimination module which calculates a ratio of an image impedance and a normal impedance of a transmission line based on system input data and uses the ratio to discriminate between an overhead line and an underground line; an assumed fault analysis module which assumes a fault of a power system facility based on overhead line or underground line information discriminated by the underground and overhead line discrimination module and performs assumed fault analysis; and a current calculation module which calculates a bus voltage, a line current, and a phase angle based on the system input data and analyzes a line overload and a bus voltage maintenance state.
By easily distinguishing between underground and overhead lines and utilizing the built-in automatic accident execution function of PSS/E, various accidents can be reviewed easily, quickly, and accurately without a separate accident list, thereby improving work efficiency.

Description

{AN APPARATUS AND A METHOD OF ANALYZING POWER SYSTEM BASED ON AUTOMATIC IDENTIFICATION OF OVERHEAD LINE AND UNDERGROUND LINE}

The present invention relates to a power system analysis device and method based on automatic identification of underground and overhead lines, and more particularly, to a power system analysis device and method that performs an assumed fault analysis based on the underground and overhead line identification results using the ratio of the image impedance and normal impedance of a transmission line.

PSS/E (Power System Simulator for Engineering), a system analysis program developed by SIEMENS PTI (Power Technologies International) in the United States, is widely used in domestic and international industries and academia. Among the various functions of PSS/E, the flow calculation review simulates problems such as overload or low voltage of the equipment that occur in the event of a failure of the transmission and substation equipment in advance and establishes solutions for them. The fault calculation review identifies the fault current flowing in or out in the event of a bus or line failure and compares it with the rated capacity of the bus to confirm the adequacy of the substation breaking capacity.

The most commonly used tidal current calculation in PSS/E first applies a hypothetical fault (hereinafter referred to as “supposed fault”) to the system in a normal or power outage state. According to the Electricity Market Operation Rules, overhead lines and overhead/underground mixed lines apply two-line simultaneous faults, and underground lines apply one-line fault. In other words, if there is even a part of an overhead section, the probability of two-line simultaneous faults due to external factors such as lightning or contact with a foreign object is high, so a two-line fault is applied. On the other hand, underground lines are installed in power cables or conduits, so the probability of two-line simultaneous faults due to external factors is low, such as a connection or cable failure, and so a one-line fault is applied.

When calculating the current and reviewing the assumed faults, the system analysis data (PSS/E input data) that contains a lot of system information such as transmission lines, transformers, generators, loads, and overhead equipment are required. However, the current system analysis input data does not contain information that can distinguish between overhead and overhead lines, making it impossible to apply the assumed faults uniformly. In other words, PSS/E has a function that can automatically perform the assumed faults for all facilities by uniformly applying a 1-line or 2-line fault to all transmission lines, but this function cannot be used because it cannot distinguish between overhead and underground lines. Therefore, currently, a cumbersome method is used in which each facility is directly selected and the assumed faults are applied based on the reviewer's experience and knowledge.

The present disclosure relates to a power system analysis device and method that performs a potential fault analysis based on the results of identifying underground and overhead lines using the ratio of the image impedance and normal impedance of a transmission line.

The present disclosure relates to a power system analysis device and method capable of easily, quickly, and accurately examining various assumed accidents without a separate assumed accident list.

A power system analysis device according to one embodiment of the present invention

Based on the system input data, it includes an underground and overhead line discrimination module which calculates a ratio of the image impedance and normal impedance of a transmission line and uses the ratio to discriminate between overhead lines and underground lines; an assumed fault analysis module which assumes a fault of a power system facility and performs assumed fault analysis based on the overhead line or underground line information discriminated by the underground and overhead line discrimination module; and a power flow calculation module which calculates bus voltage, line current, and phase angle based on the system input data and analyzes line overload and bus voltage maintenance status.

The above power system analysis device may further include a state estimation module that corrects errors in acquired data and estimates unacquired data based on generator measurement values, transmission and substation measurement values, and system data acquired through SCADA; and a system analysis database that stores generator measurement values, transmission and substation measurement values, and system data for which errors have been corrected by the state estimation module.

The above-mentioned assumed accident analysis module can assume a failure of the power system equipment based on data stored in the system analysis database and information on overhead lines and underground lines determined by the above-mentioned underground and overhead line determination module.

The above-mentioned assumed accident analysis module can perform assumed accident analysis by applying a two-line fault collectively in the case where the underground and overhead line discrimination module determines that the line is an underground or mixed line, and can perform assumed accident analysis by applying a one-line fault collectively in the case where the underground and overhead line discrimination module determines that the line is an overhead line.

The above-mentioned underground and overhead line discrimination module can discriminate between the overhead line and the underground line by comparing the ratio of the image impedance and normal impedance of the above-mentioned transmission line with the line discrimination reference value.

At this time, the underground and overhead line discrimination module can discriminate as an overhead line if the ratio of the image impedance and normal impedance of the transmission line exceeds the line discrimination criterion value, and can discriminate as an underground line if the ratio of the image impedance and normal impedance of the transmission line does not exceed the line discrimination criterion value. The line discrimination criterion value can be set to a value between 0.99 and 1.86.

A power system analysis method according to one embodiment of the present invention

It includes a first step of acquiring normal impedance and image impedance of a transmission line; a second step of securing a ratio of normal impedance and image impedance of the transmission line based on the acquired normal impedance and image impedance; a third step of determining whether the transmission line is an underground line or an overhead line based on a comparison result of the ratio of the normal impedance and image impedance and a line determination criterion value; and a fourth step of performing an assumed accident analysis based on the determination result of the underground line or the overhead line.

The above power system analysis method may further include a fifth step of analyzing line overload and bus voltage maintenance status by calculating bus voltage, line current, and phase angle based on system analysis data.

The above power system analysis method performs steps 1 to 4 when the number of transmission line circuits included in the system analysis data is two or more.

In the fourth step above, if the judgment result of the third step is an underground line or a mixed line, a two-line fault can be applied uniformly to perform an assumed accident analysis, and if the judgment result of the third step is an overhead line, a one-line fault can be applied uniformly to perform an assumed accident analysis.

In the third step, if the ratio of the image impedance and the normal impedance exceeds the line discrimination criterion value, the line can be discriminated as the overhead line, and if the ratio of the image impedance and the normal impedance of the transmission line does not exceed the line discrimination criterion value, the line can be discriminated as the underground line. At this time, the line discrimination criterion value can be set to a value between 0.99 and 1.86.

By easily distinguishing between underground and overhead lines and utilizing the built-in automatic accident execution function of PSS/E, various accidents can be reviewed easily, quickly, and accurately without a separate accident list, thereby improving work efficiency.

In addition, system sophistication can be achieved by eliminating the need to create and modify thousands of assumed accident lists required by the currently operating power system analysis system.

FIG. 1 is a block diagram schematically showing a power system analysis device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an example of a computer device according to an embodiment of the present invention.
Figure 3 is a diagram showing the equipment information required for system analysis data.
Figures 4 and 5 are diagrams showing self-inductance and mutual inductance, respectively.
Figures 6 and 7 are diagrams showing the normal impedance and image impedance of a transmission line, respectively.
Figure 8 is a distribution diagram showing the ratio of image impedance to normal impedance by section.
Figure 9 is a flowchart showing the overall operation of determining underground and overhead lines (mixed lines) using transmission line impedance.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are assigned similar drawing reference numerals throughout the specification.

Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

In addition, terms such as “……part,” “……unit,” and “……module” described in the specification mean a unit that processes at least one function or operation, which can be implemented by hardware, software, or a combination of hardware and software.

The devices described in the present invention are composed of hardware including at least one processor, a memory device, a communication device, etc., and a program that is executed by being combined with the hardware in a designated location is stored. The hardware has a configuration and performance capable of executing the method of the present invention. The program includes instructions that implement the operating method of the present invention described with reference to the drawings, and executes the present invention by being combined with hardware such as a processor and a memory device.

As used herein, “transmitting or providing” may include not only direct transmission or providing, but also indirect transmission or providing via another device or by using a bypass route.

In this specification, expressions described in the singular may be interpreted as singular or plural, unless explicit expressions such as “one” or “singular” are used.

Figure 1 schematically illustrates a power system analysis device (100) according to an embodiment of the present invention.

The power system analysis device (100) automatically creates power system analysis data by utilizing real-time measurement data acquired through the SCADA system, and automatically applies various assumed accidents to notify the power system operator of problems such as overload and low voltage. The SCADA (Supervisory Control And Data Acquisition) system refers to a computer system that monitors and controls facilities based on industrial processes/infrastructure/equipment. In general, the SCADA system is composed of a device for human-machine interface, a device in charge of the supervisory control process, a communication device that can collect data and issue actual commands for control, and a field control and monitoring device. The SCADA system is characterized by the fact that it can be remotely controlled, and has the advantage of being able to operate and recover from failures of power facilities through efficient and rapid control, and being able to quickly perform an emergency shutdown of power facilities in an emergency situation.

In the existing power system analysis system, in order to review essential assumed faults, a list of assumed faults for hundreds or thousands of 1-2 line transmission lines had to be created one by one in Excel, and if there were changes to the system such as the construction or expansion of transmission lines, there was the inconvenience of having to modify the list of assumed faults one by one.

The power system analysis device (100) according to the embodiment of the present invention has implemented a method for determining underground and overhead lines (including mixed lines) using only the transmission line impedance included in the input data (PSS/E data) acquired through the SCADA system. In this way, if underground and overhead lines are easily distinguished and the automatic assumed accident execution function built into the PSS/E itself is used, anyone can easily, quickly, and accurately review assumed accidents for various assumed accidents without a separate assumed accident list.

In Fig. 1, the power system analysis device (100) includes a state estimation module (110), a system analysis database (120), an underground and overhead line determination module (130), an assumed accident analysis module (140), and a current calculation module (150).

The state estimation module (110) is a part that provides accurate system operation data by correcting errors in acquired data and estimating unacquired data based on generator measurement values, transmission and substation measurement values, and system data (topology, impedance, etc.) acquired through SCADA. The estimation result of the state estimation module (110) is stored in the system analysis database (120).

The underground and overhead line identification module (130) obtains the ratio of the image impedance and normal impedance of the transmission line based on the data stored in the system analysis database (120) or the system input data transmitted from the SCADA system, and automatically identifies overhead lines and underground lines (including mixed lines) using this.

The system analysis database (120) stores generator measurement values, transmission and substation measurement values, and system data (topology, impedance, etc.) that have been error-corrected by the state estimation module (110).

The assumed accident analysis module (140) assumes a fault in power system equipment based on data stored in the system analysis database (120) and information on overhead lines and underground lines determined by the underground and overhead line determination module (130), analyzes the power system operation status, and reflects the power system status in the event of a assumed accident to the system operation. Specifically, the assumed accident analysis module (140) performs assumed accident analysis by uniformly applying a two-line fault to underground lines (including mixed lines) determined by the underground and overhead line determination module (130), and performs assumed accident analysis by uniformly applying a one-line fault to overhead lines.

The current calculation module (140) calculates bus voltage, line current, phase angle, etc. based on data stored in the system analysis database (120) to analyze line overload and bus voltage maintenance status. The current calculation module (140) can optimize the solution of a function by using a system module common to other system application programs, and can also use the optimized state in other functions.

FIG. 2 is a block diagram illustrating an example of a computer device according to an embodiment of the present invention. The power system analysis device described in FIG. 1 can be implemented by the computer device (200) illustrated in FIG. 2.

The computer device (200) may include a memory (210), a processor (220), a communication interface (230), and an input/output interface (240), as illustrated in FIG. 2. The memory (210) may be a computer-readable storage medium, and may include a random access memory (RAM), a read only memory (ROM), and a permanent mass storage device such as a disk drive. Here, the permanent mass storage devices such as the ROM and the disk drive may be included in the computer device (200) as a separate permanent storage device distinct from the memory (210). In addition, the memory (210) may store an operating system and at least one program code. These software components may be loaded into the memory (210) from a computer-readable storage medium separate from the memory (210). The separate computer-readable storage medium may include a computer-readable storage medium such as a floppy drive, a disk, a tape, a DVD/CD-ROM drive, a memory card, etc. In another embodiment, the software components may be loaded into the memory (210) via a communication interface (230) other than a computer-readable recording medium. For example, the software components may be loaded into the memory (210) of the computer device (200) based on a computer program that is installed by files received over a network (300).

The processor (220) may be configured to process instructions of a computer program by performing basic arithmetic, logic, and input/output operations. The instructions may be provided to the processor (220) by the memory (210) or the communication interface (230). For example, the processor (220) may be configured to execute instructions received according to program code stored in a storage device such as the memory (210).

The communication interface (230) may provide a function for the computer device (200) to communicate with other devices (for example, the storage devices described above) via the network (300). For example, requests, commands, data, files, etc. generated by the processor (220) of the computer device (200) according to program codes stored in a recording device such as a memory (210) may be transmitted to other devices via the network (300) under the control of the communication interface (230). Conversely, signals, commands, data, files, etc. from other devices may be received by the computer device (200) via the communication interface (230) of the computer device (200) via the network (300). Signals, commands, data, etc. received via the communication interface (230) may be transmitted to the processor (220) or the memory (210), and files, etc. may be stored in a storage medium (the permanent storage device described above) that the computer device (200) may further include.

The input/output interface (240) may be a means for interfacing with an input/output device (250). For example, the input device may include a device such as a microphone, a keyboard, or a mouse, and the output device may include a device such as a display or a speaker. As another example, the input/output interface (240) may be a means for interfacing with a device that integrates input and output functions into one, such as a touch screen. The input/output device (250) may be configured as a single device with the computer device (200).

Also, in other embodiments, the computer device (200) may include fewer or more components than the components of FIG. 2. However, it is not necessary to explicitly illustrate most of the conventional components. For example, the computer device (200) may be implemented to include at least some of the input/output devices (250) described above, or may further include other components such as a transceiver, a database, etc.

According to the power system analysis device (100) according to an embodiment of the present invention, the PSS/E system analysis data, which is input data, is composed of tens of thousands of pieces of information, such as a bus, a generator, a power line, a load, a transmission line, and a transformer.

Figure 3 shows the equipment information required for the system analysis data. Here, the base value is a value that the reviewer pre-specifies and inputs in order to obtain an unknown value. The unknown value is a calculated value that comes out through the PSS/E program's flow calculation simulation process. In the embodiment of the present invention, the transmission line impedance can be calculated by a dedicated calculation program or determined in advance through actual measurement.

Among the base values in Figure 3, the impedance (R, X) and charging capacity (C) of the transmission line, the impedance (X) and tap (X) of the transformer, and the impedance (X) of the generator always maintain constant values unless there is new construction.

Table 1 is a standard constant table for transmission lines used when reviewing a system plan. Since transmission lines scheduled for construction in the future are planned facilities that do not actually exist, their impedances cannot be measured or calculated. In such cases, the standard constant table for transmission lines can be used to input the system analysis data and conduct a system review.

In Table 1, the normal impedance (R1, X1) and the image impedance (R0, X0) per km are determined in advance by overhead, underground, voltage, line type, and specification. The overhead line impedance is determined by the conductor material, wire arrangement, and distance between wires, and in the case of underground lines, it is determined by the cable standard, cable center spacing, conductor outer diameter, sheath standard, and conductor resistance. Because of the characteristics of each wire type and specification, it is difficult to distinguish between underground and overhead transmission lines with only the impedance per km.

Looking at the ratio of image impedance to normal impedance (Z0/Z1) in Table 1, the range for overhead lines is 2.42 to 3.60, with an average of 2.81. For underground lines, it is 0.32 to 0.99, with an average of 0.58. Therefore, it can be seen that the ratio of image and normal impedance allows a clear distinction between underground and overhead lines.

Meanwhile, it can be proven that the image impedance of the overhead line is approximately three times larger than the normal impedance as follows.

In a three-phase, three-wire overhead transmission line, impedance can be divided into self-inductance (Ls) to ground, mutual inductance (Lm) to ground, and working inductance (L).

As shown in Fig. 4, the magnetic inductance (Ls) of the earth conductor is the inductance caused by the magnetic flux generated by its own phase current and the magnetic flux linking with its own phase conductor, and the actual measured value is 2.4 [mH/km].

As shown in Fig. 5, the mutual inductance (Lm) of the earth-earth loop is the inductance generated when the magnetic flux generated by the current of another phase interlinks with its own phase, and the actual measured value is 1.1 [mH/km].

The working inductance (L) is the inductance due to all magnetic fluxes interlinked in one phase of the wire, and is the sum of self-inductance and mutual inductance. The inductance of a transmission line that we commonly refer to is the working inductance.

As illustrated in Fig. 6, the normal impedance of a transmission line is an impedance obtained from the relationship between the three-phase symmetrical current flowing and the applied voltage when a normal rotating three-phase symmetrical voltage is applied to the three-phase power equipment terminal (Z1 = V1/I1). The working inductance and normal impedance of the line can be obtained using the measured values of self-inductance and mutual inductance mentioned above. In Fig. 6, the normal impedance X1 is obtained as the vector sum of self-inductance (Ls(I _a )) and mutual inductance (Lm (I _b ), Lm (I _c )), as in the following mathematical expression 1.

As shown in Fig. 7, the image impedance is the impedance obtained from the relationship between the image current having the same magnitude and phase flowing through the three phases through the ground return path and the applied image voltage when a single-phase voltage is applied to the three-phase power equipment terminals at once (Z0 = V0/I0). The image impedance is obtained by the scalar sum because the phases of each phase are the same. In Fig. 7, the normal impedance X0 is obtained by the following mathematical expression 2.

From mathematical expressions 1 and 2, when examining the relationship between the normal impedance and the image impedance of the overhead transmission line, the image impedance is calculated to be 1.73 [Ω/km] and the normal impedance is 0.49 [Ω/km], and it can be seen that the image impedance is about 3 times larger than the normal impedance. Therefore, the average ratio of the image impedance to the normal impedance (Z0/Z1 ≒ 2.8 times) confirmed in the standard constants of transmission lines in Table 1 can be considered valid.

Meanwhile, when classifying transmission lines, there are overhead transmission lines, underground transmission lines, and mixed transmission lines that are both overhead and underground. Since mixed lines also have overhead sections, a two-line fault is assumed. However, there is no standard constant for mixed transmission lines, as shown in Table 1, so it is not possible to confirm whether they can be distinguished by the ratio of zero and normal impedances.

Therefore, in the embodiment of the present invention, by examining the impedance of an actual operating transmission line, ① the trend of the ratio of the image impedance to the normal impedance (Z0/Z1) of a mixed transmission line and ② whether it is possible to distinguish between underground, overhead lines, and mixed lines using the Z0/Z1 value are confirmed.

The normal and zero-phase impedances of underground and overhead lines were compared for 223 transmission lines of 154 kV or higher at the Daejeon-Sejong-Chungnam headquarters of Korea Electric Power Corporation.

Table 2 shows the normal image impedance (%Z0) and normal impedance (%Z1) per unit length of underground, overhead, and mixed lines, and Table 3 shows the ratio of the image impedance to normal impedance of underground, overhead, and mixed lines.

In Table 3, both 765kV and 345kV are overhead lines, and the ratios of image impedance and steady-state impedance (Z0/Z1) are 2.47~2.50 and 2.61~3.27, respectively. The 154kV line consists of underground, overhead, and mixed (underground+overhead) lines, and the ratios of Z0 and Z1 are 0.42~0.98, 2.37~3.68, and 1.87~3.53, respectively.

Figure 8 is a distribution diagram showing the ratio of Z0 and Z1 by section. In Figure 8, it can be seen that underground lines and overhead and mixed lines are clearly distinguished. The Z0/Z1 value of underground lines is at most 0.98, and that of overhead and mixed lines is at least 1.87, so if the line discrimination criterion value is set between 0.99 and 1.86, underground lines and overhead and mixed lines can be distinguished using only the image and normal impedance of the transmission line.

Figure 9 is a flowchart showing the overall operation of determining underground and overhead lines (mixed lines) using transmission line impedance.

The underground and overhead line determination module (130) acquires system analysis data (PSS/E system review data) directly from the system analysis database (120) or the SCADA system (S10), and then determines whether the number of transmission line lines included in the system analysis data is 1 line or 2 lines (S20).

As a result of the judgment in the above step S20, if the transmission line is a single line, there is no need for overhead lines and underground lines, so the assumed accident analysis module (150) applies a single-line assumed accident and performs the assumed accident analysis. (S90)

In the judgment result of the above step S20, if the transmission line has two or more lines, the normal impedance and image impedance of the transmission line are acquired. (S30) At this time, the normal impedance and image impedance of the transmission line are calculated by a dedicated program or determined in advance through actual measurement. Thereafter, based on the acquired normal impedance (Z1) and image impedance (Z0), the ratio of the image impedance and the normal impedance (Z0/Z1) is calculated. (S40)

Thereafter, the underground and overhead line determination module (130) determines whether the ratio of the image impedance to the normal impedance exceeds the line determination criterion value. (S50) At this time, the line determination criterion value can be set to any value between 0.99 and 1.86, and in the embodiment of the present invention, 1.2 is set as the line determination criterion value.

If the ratio of the image impedance and the normal impedance does not exceed the line determination criterion value as a result of the judgment in the above step S50, the underground and overhead line determination module (120) determines that it is an underground line, and (S80) the assumed accident analysis module (150) applies a single-line assumed accident to perform assumed accident analysis. (S90)

If the ratio of the image impedance and the normal impedance exceeds the line determination criterion value as a result of the judgment in the above step S50, the underground and overhead line determination module (120) determines that it is an overhead or mixed line (S60), and the assumed accident analysis module (150) performs the assumed accident analysis by applying a two-line assumed accident (S70).

After performing the assumption analysis, (S70, S90) the current calculation module (140) calculates the bus voltage, line current, phase angle, etc. based on the data stored in the system analysis database (120) to analyze the line overload and bus voltage maintenance status. (S100)

In this way, according to an embodiment of the present invention, by easily distinguishing between underground and overhead lines and utilizing the automatic accident execution function built into the PSS/E, it is possible to easily, quickly, and accurately review various accidents without a separate accident list, thereby improving work efficiency.

In addition, system sophistication can be achieved by eliminating the need to create and modify thousands of assumed accident lists required by the currently operating power system analysis system.

The embodiments described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program may be recorded on a computer-readable medium. At this time, the medium may include a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD, a magneto-optical medium such as a floptical disk, and a hardware device specifically configured to store and execute program instructions, such as a ROM, a RAM, a flash memory, and the like.

Unless there is an explicit description or contradiction of the order of steps constituting the method according to the embodiments, the steps may be performed in any suitable order. The invention is not necessarily limited to the order in which the steps are described. The use of all examples or exemplary terms (e.g., etc.) in the present invention is merely for the purpose of describing the invention in detail and does not limit the scope of the present invention due to this. In addition, those skilled in the art will recognize that various modifications, combinations, and changes can be made within the scope of the claims or their equivalents.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art in the art to which the present invention pertains also fall within the scope of the present invention.

100. Power system analysis, 110 state estimation module, 120 system analysis DB
130. Underground and overhead line identification module, 140., Assumed accident analysis module
150. Bird counting module, 200. Computer device

Claims (15)

An underground and overhead line discrimination module that calculates the ratio of the image impedance and normal impedance of a transmission line based on system input data and uses this to discriminate between overhead lines and underground lines;
A presumed accident analysis module that presumes a fault in power system equipment and performs presumed accident analysis based on overhead line or underground line information determined by the above-mentioned underground and overhead line determination module;
A current calculation module that calculates bus voltage, line current, and phase angle based on the above system input data and analyzes line overload and bus voltage maintenance status;
A state estimation module that corrects errors in acquired data and estimates unacquired data based on generator measurement values, transmission and substation measurement values, and system data acquired through SCADA; and
A system analysis database that stores generator measurement values, transmission and substation measurement values, and system data that have been error-corrected by the above state estimation module.
A power system analysis device including a . delete In paragraph 1,
The above-mentioned assumed accident analysis module is a power system analysis device that assumes a failure of the power system equipment based on data stored in the system analysis database and information on overhead lines and underground lines determined by the above-mentioned underground and overhead line determination module. In paragraph 1,
The above assumption analysis module is
If the above-mentioned underground and overhead line identification module determines that the line is underground or a mixed line, a two-line fault is applied uniformly to perform an assumed accident analysis.
A power system analysis device that performs an analysis of assumed accidents by applying a single-line fault collectively in the case of an overhead line as determined by the above-mentioned underground and overhead line identification module. In any one of paragraphs 1, 3 and 4,
The above-mentioned underground and overhead line discrimination module is a power system analysis device that compares the ratio of the image impedance and normal impedance of the above-mentioned transmission line with the line discrimination reference value to discriminate between the above-mentioned overhead line and underground line. In Article 5,
The above-mentioned underground and overhead line identification module
A power system analysis device that determines that the overhead line is the above-mentioned line if the ratio of the image impedance and normal impedance of the above-mentioned transmission line exceeds the line determination criterion value, and determines that the overhead line is the above-mentioned line if the ratio of the image impedance and normal impedance of the above-mentioned transmission line does not exceed the line determination criterion value. In Article 6,
A power system analysis device in which the above line determination criterion value is set to a value between 0.99 and 1.86. The first step is to obtain the normal impedance and image impedance of the transmission line;
A second step of securing a ratio of normal impedance and image impedance of the transmission line based on the normal impedance and image impedance acquired above;
A third step of determining whether a line is underground or overhead based on the comparison result of the ratio of the above normal impedance and image impedance and the line determination criterion value;
A fourth step of performing an analysis of the assumed accident based on the determination results of the above underground or overhead lines; and
The fifth step is to analyze line overload and bus voltage maintenance status by calculating bus voltage, line current, and phase angle based on system analysis data.
A power system analysis method including: delete In Article 8,
A power system analysis method for performing steps 1 to 4 above when the number of transmission line circuits included in the system analysis data is two or more. In Article 10,
The fourth step above is
In the case of underground or mixed lines as a result of the judgment in the third step above, a two-line fault is applied uniformly to conduct an analysis of the assumed accident.
A power system analysis method that performs an assumed accident analysis by applying a single-line fault uniformly in the case of an overhead line as a result of the judgment in the third step above. In Article 10,
The third step above is
A power system analysis method wherein if the ratio of the image impedance and normal impedance exceeds the line discrimination criterion value, the line is discriminated as the overhead line, and if the ratio of the image impedance and normal impedance of the transmission line does not exceed the line discrimination criterion value, the line is discriminated as the underground line. In Article 12,
A power system analysis method in which the above line determination criterion value is set to a value between 0.99 and 1.86. A computer-readable recording medium having recorded thereon a computer program for executing the method of any one of claims 8 and 10 to 13 on a computer device. Comprising at least one processor implemented to execute computer-readable instructions,
By at least one processor,
Obtain the normal impedance and image impedance of the transmission line,
Based on the normal impedance and image impedance acquired above, the ratio of the normal impedance and image impedance of the transmission line is secured,
Based on the comparison result of the ratio of the above normal impedance and image impedance and the line identification criterion value, the underground line or overhead line is identified,
A computer device that performs an analysis of a potential accident based on the results of the determination of the above-mentioned underground or overhead line.