KR101243216B1 - Control system for detecting a electric power chain in wide area - Google Patents

Abstract

PURPOSE: A wide area monitoring and control system for power systems is provided to obtain the size and the phase angle of a voltage for the entire bus of a power system by running a state estimation algorithm based on scalar data and network topology. CONSTITUTION: An EMS(Energy Management System) generates EMS data. A WAMAC(Wide Area Monitoring And Control) receives only EMS data from a power management part at five minutes intervals and then extracts integral data integrating EMS data and PMU(Phasor Measurement Unit) data. The WAMAC substitutes the integral data for a hybrid SE(State Estimation) execution condition, constructs hybrid SE input with the integral data and power system topology data, and then extracts second hybrid SE data minimizing the errors of first hybrid SE data generated by the process mentioned above.

Description

Control System for detecting a Electric Power Chain in Wide Area

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to power control technology, and more particularly, to a wide area power system monitoring control system in which PMU data and EMS state estimation data are applied to a hybrid state estimation technique.

For the analysis of the power system, the information of the power system is represented by the IEEE method and Siemens' PTI PSS / e format most commonly. In general, the power company adopts the PTI PSS / e format. PTI PSS / e was developed in 1976 by PTI, Inc., and is a software program for simulating, analyzing, and optimizing power system characteristics such as power grid and power generation evaluation under static and dynamic state conditions. The PSS / e program can perform power flow calculation, balanced and unbalanced fault analysis, network reduction, and dynamic simulation.

In addition, with the restructuring of the power industry in many countries around the world, Optimal Power Flow, Transfer Limit Analysis, and Open Access and Pricing, which are required for economic system operation in the power market, It is developed to be possible. In Korea, the PSS / e program has been introduced and used in academics, research institutes, and power companies since the 1980s. It is one of the most used programs in the operation of power systems.

However, the conventional technology has a problem that it is difficult to secure the visibility of the power system because the conventional RTU data does not match the time synchronization between the RTU data and is transmitted as a scalar value, resulting in nonlinearity requiring the phase angle.

Wide area power system monitoring control system of the present invention was devised to solve the problems of the prior art, the first object of the present invention is transmitted from a remote terminal unit (RTU) installed in the field in the existing EMS (Energy Management System) This is to obtain the magnitude and phase angle of the voltage for the entire bus line of the power system by performing a state estimation algorithm based on the scalar data of the voltage, current, and reactive power.

The second object of the present invention is to use a PMU (Phasor Measurment Unit) in the main power generation / substation when using the acquisition data instead of the RTU data to solve the non-linear equations to obtain the voltage phase angle when using the phase angle information of the PMU This is to improve the precision by solving with linear equations.

The third object of the present invention is to secure the visibility of the power system by improving the state estimation result of the entire system using the accurate PMU data of the main power generation / substation data, and to improve the system operation.

The present invention for achieving the above object includes the following configuration.

That is, the hybrid state estimation system according to an embodiment of the present invention, the power management unit for generating EMS data; And receiving only EMS data from the power management unit every 5 minutes, extracting integrated data incorporating EMS data PMU data, and substituting the integrated data into hybrid SE execution conditions, if appropriate, integrating the integrated data and power system topology. The data comprises a hybrid SE input, and then broadband monitoring and control for extracting second hybrid SE data that minimizes the error of the first hybrid SE data generated thereby.

The wide area power system monitoring and control system of the present invention uses a state estimation algorithm based on the scalar data and network topology of voltage, current, and reactive power transmitted from a remote terminal unit (RTU) installed in an existing EMS (Energy Management System). The first effect is to obtain the magnitude and phase angle of the voltage for the entire power system.

According to the present invention, when a PMU (Phasor Measurment Unit) is installed in a main power generation / substation and the acquired data is used instead of the RTU data, a nonlinear equation must be solved to obtain a voltage phase angle. It is possible to give the second effect that the precision is improved.

The present invention improves the state estimation result of the entire system by using the accurate PMU data of the main power generation and substation data, thereby ensuring the visibility of the power system, and has a third effect of improving the system operation.

1 is a system configuration diagram of each layer of a wide area power system monitoring control system according to an embodiment of the present invention.
2 is a flowchart illustrating a hybrid state estimation technique according to an embodiment of the present invention.

[Example]

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

1 is a system configuration diagram of each layer of a wide area power system monitoring control system according to an embodiment of the present invention.

Referring to FIG. 1, a wide-area power system monitoring and control system is a system developed for the purpose of rapidly monitoring the entire power system in real time and responding to an abnormal symptom, and is called PMU (Phasor Measurement Unit) in a major power system / substation. Terminal equipment is installed, and this PMU measures current and voltage from CT of power transmission line and PT of bus line to obtain Phasor value through Signal Processing method based on GPS time signal, and calculates Phasor value to GPS time It is a mechanical device that transmits data to RCC (Regional Control Center) level operating system in accordance with IEEE C37.118-2005 standard. The data to be transmitted is GPS time, voltage phasor, current phasor, active power, reactive power, frequency, etc., and the transmission period is 16ms.

However, due to the high price of PMUs, it is difficult to install them in all power generation and substations of power systems.Wide-area power system monitoring and control systems without power system topology information can determine the topology of power systems using only PMU data. none.

To compensate for this, the information of the energy management system (EMS), which is used to operate the system at the existing power exchange, is used to improve the precision of the wide area power system monitoring and control system.

EMS (Energy Management System) installs RTU (Remote Terminal Unit) at all power generation and substations, and acquires data from power system for transmission. At this time, the data transmitted from the RTU is voltage size, current size, active power, reactive power, breaker information, etc., and the transmission period is a 10 second period.

However, in the EMS, the time synchronization of information transmitted by polling method in each RTU is incorrect, and data transmission or a wrong value may be transmitted due to communication failure and measurement error. To solve this problem, EMS performs an algorithm called State Estimation to grasp the state of the entire power system.

Here, state refers to voltage magnitude and phase information of all buses (buses), and state estimation is an algorithm for estimating voltage magnitude and phases of all buses. However, as mentioned above, there is uncertainty due to the time synchronization between the data, which does not reflect the exact power system status, but it does not cause a big problem when operating the power system at the worst condition.

In order to improve these limitations, it is intended to improve the accuracy of the state estimation by linking the wide area power system monitoring control system and the EMS. This patent is about the methodology for improving the state estimation of the EMS.

The state estimation algorithm in EMS is performed every 2 ~ 3 minutes and the result can be provided to external system in PTI PSS / e format. The operating system of the GCC (Gird Control Center) layer of the wide area power system monitoring / control (WAMAC) system receives the status estimation result data of the power management system every five minutes from the power management system, It constructs integrated data combining PMU (Phasor Measurement Unit) data, and performs hybrid state estimation from the established integrated data if it fits into the condition of performing hybrid state estimation.

Busbar number Substation Name Reference voltage area zone Voltage size Voltage phase possession 160 'Anduk' 154 One 0 0 12 15 1.04266 -16.5728 One 161 'Andeok 1MTR' 22.9 One 0 0 12 23 1.01 -20.1689 One 162 'Andeok 2MTR' 22.9 One 0 0 12 23 1.01042 -22.1239 One 170 Namjeju 154 One 0 0 12 15 1.04399 -16.2151 One 180 'Shinseogwi' 154 One 0 0 12 15 1.03443 -17.6642 One 181 'Shinseo 1MTR' 22.9 One 0 0 12 23 1.0191 -22.6205 One 182 'Shinseo 2MTR' 22.9 One 0 0 12 23 1.01419 -21.0463 One 190 Halla 154 One 0 0 12 15 1.03561 -17.8159 One 191 Halla 1MTR 22.9 One 0 0 12 23 1.01859 -24.0317 One 192 Halla 2MTR 22.9 One 0 0 12 23 1.0185 -22.1727 One

Table 1 shows the Jeju system data. In the above format, the voltage and phase of each bus and corresponding substation are expressed in phase. When the values in this table are transmitted to the WAMAC system, WAMAC replaces the bus data of the substation where the PMU is installed with the PMU acquisition value. .

For example, if the voltage value of bus 190 of Halla substation is 1.03561∠17.8159 and the PMU acquisition value is 1.1654∠-15.0876, changing the voltage magnitude and phase to PMU value in the table above becomes the integrated data. Is used as the input data for the hybrid state estimation, and the result of the hybrid state estimation algorithm is expressed in the same format by newly calculating the voltage magnitude and phase for the entire bus.

Hybrid state estimation is performed by using the tidal current data measured by the RTU and the PMU based on the bus value determined by the PMU data. The RTU data is contained in the PSS / e format file, and the PMU data uses the values in the real time database.

Subsequently, the wide area power system monitoring and control system includes an EMS data linkage unit for receiving EMS data, a relation-database for storing EMS data, a PMU data linkage unit for receiving PMU data, and a real-time database for storing PMU data. (Real Time-DataBase), divided into power system topology database that stores power system topology data, and power system topology DB is included in branch data of PSS / e format data, which is the result of EMS status estimation, do.

Here, it is noted that the EMS data is the result data of the PSS / e format with the state estimation result value, and the result data of the PSS / e format includes the network topology information and the magnitude and phase information of the voltage which is the result of the state estimation algorithm.

In addition, the wide-area power system monitoring control system further includes a hybrid state estimation processor for extracting the result data by performing a hybrid SE according to the EMS data, PMU data and power system topology data to the hybrid state estimation algorithm.

The hybrid state estimation result is a value that is more precisely improved than the existing state estimation result of the EMS, and shows the magnitude and phase of the voltages and phases of the entire system and all the buses. Based on this, the tide analysis, failure analysis, transient stability analysis, Used as basic data for voltage stability analysis.

The hybrid state estimation processing unit preprocesses the error for EMS data, the data integration unit for generating integrated data by integrating EMS data and PMU data, the execution condition acquisition unit for assigning the integrated data to the hybrid SE execution condition, and when appropriate An input unit configured to form a hybrid SE input using the integrated data and the power system topology data, an error performing unit that minimizes the error of the first hybrid SE data generated thereby, and an output unit extracting the hybrid SE data by the error performing unit. And a use screen display unit for displaying the second hybrid SE data on the screen.

2 is a flowchart illustrating a hybrid state estimation technique according to an embodiment of the present invention.

Referring to FIG. 2, EMS data acquisition is performed every five minutes from the EMS, and is acquired in PSS / e format. The acquired data must go through the error data preprocessing unit to indicate whether there is error data, which is based on operating conditions (convergence conditions, abnormal conditions). For example, it is determined whether there is a value exceeding a reference voltage allowable range among the voltage data. The next step is to integrate the PMU data obtained from WAMAC. Receives input from the operator of the hybrid condition estimation performance condition, constructs the network topology from the topology configuration data of the power system from the information in the PSS / e format to form the basic form for the hybrid state estimation, and based on the PMU acquisition value and EMS data By using the weighted least squares method, error minimize is performed. The most modern technique for solving the weighted least squares problem is the Orthogonal Transformation Method. The main advantage of this method is that it guarantees good numerical robustness in the Central Estimation Solution, which solves the problem of not being harmed by severe malignant conditions in early methodologies such as the Normal Equation approach.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. Will understand.

1000: wide area power system monitoring and control system

Claims (5)

A power management unit (EMS) for generating EMS data;
After receiving only EMS data from the power manager every 5 minutes, extract the integrated data incorporating the EMS data PMU data, and substituting the integrated data into the hybrid SE execution conditions, if appropriate, the integrated data and power system topology data And a broadband monitoring and control unit (WAMAC) configured to configure a hybrid SE input, and then extract second hybrid SE data that minimizes the error of the first hybrid SE data generated thereby.
The method of claim 1, wherein the broadband monitoring and control unit,
An EMS data linker which receives the EMS data;
An R-DB storing the EMS data;
A PMU data linker for receiving PMU data;
RT-DB for storing PMU data;
A power system topology DB unit for storing power system topology data;
And a hybrid state estimation processor for extracting the second hybrid SE data as the EMS data, the PMU data, and the power system topology data are applied to a hybrid state estimation algorithm.
The method of claim 2, wherein the hybrid state estimation processing unit,
A preprocessor for preprocessing the error for the EMS data;
A data integration unit for generating integrated data by integrating the EMS data and the PMU data;
An execution condition acquisition unit which substitutes the integrated data into the hybrid SE execution condition;
An input configuration unit constituting a hybrid SE input of the integrated data and the power system topology data when it is reasonable;
An error performing unit for minimizing an error of the first hybrid SE data generated thereby;
An output unit for extracting second hybrid SE data minimized by the error performing unit; And
And a use screen display unit for displaying the second hybrid SE data on the screen.
The method of claim 1,
The EMS data is a hybrid state estimation system, characterized in that the result data in PSS / e format with a state estimation result value.
The method of claim 4, wherein the result data of the PSS / e format,
Hybrid state estimation system, characterized in that it includes network topology information and voltage magnitude and phase information as a result of state estimation algorithm.

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