JP2012080707A - Apparatus for estimating equipment data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for estimating equipment data capable of supplying equipment data with high accuracy at a time point when data for a state of a power system is required.SOLUTION: An observation data measuring apparatus 11 measures time-adjusted observation data of each node belonging to a power system. Equation generating means 15 generates equations where the size of bus voltage, phase, active power, and reactive power at each node among the observed data measured by the observation data measuring apparatus 11 are used as constants, while equipment data are used as variables. Equipment data calculating means 16 solves the equations generated by the equation generating means 15 so as to calculate equipment data with high accuracy.

Description

  The present invention relates to a facility data estimation apparatus that estimates facility data of a power system used when calculating a power flow of the power system.

  In order to grasp the grid state of the power system, it is necessary to grasp the power flow state of the power system. For this purpose, the magnitude and phase of the bus voltage are observed or estimated. In the estimation calculation, a state where the deviation between the value calculated from the power system analysis facility data (hereinafter referred to as facility data) and the power system observation data (hereinafter referred to as observation data) is minimized is obtained.

  Power system tidal current estimation (hereinafter tidal current calculation) uses power and supply sources such as loads and generators as nodes, and facilities between nodes (transmission lines, transformers, phase adjustment equipment, etc.) as branches. The branch power between the nodes is obtained from the relationship between the node voltage and current.

  In this power flow calculation, as the calculation conditions for the nodes, two of the active power P, reactive power Q, voltage V, and voltage phase angle θ of each node are known and the remaining two are treated as unknown. By combining known and unknown elements, a power flow equation is created to determine the magnitude and phase of the node voltage. In order to obtain the solution of the tidal current equation, for example, the Newton-Raphson method is employed (see, for example, Patent Document 1).

  That is, the power system equipment data is known, and the branch power is calculated using the unknown node voltage as a variable using the known active power P, reactive power Q, voltage V, and voltage phase angle θ. The voltage and phase between nodes in such a state that the deviation between the branch power and the observed node power is minimized is obtained, and the branch power between the nodes is obtained from the relationship between the obtained voltage and phase between the nodes. In addition, the facility data uses design values, factory test values, and partially measured values for each facility as known values.

In general, the power flow equation of the branch between the i node and the j node can be described by the equation (1).

  When this is expressed as a general expression as a vector, it is expressed by expression (2).

[Equation 2]
p = f (v) (2)
v is a voltage vector made up of the magnitude and phase angle of the node voltage, and p is a specified value vector made up of active and reactive power injected into the generator bus, and in other buses, the effective and reactive power injected into the bus. is there.

  In the tidal current calculation, the equation of each node shown in the equation (2) is a simultaneous equation, the facility data (the admittance matrix of the system composed of transmission lines, etc.) and the specified value vector p are given as fixed values, and the voltage vector v is Solved by numerical calculation as a variable.

  FIG. 3 is an explanatory diagram of a procedure for grasping a system state of a conventional power system. Observation data (the magnitude and phase of the bus voltage) at the node of the power system is obtained (S1). This observation data is data including measurement errors and synchronization deviations. On the other hand, the equipment data is obtained as values such as design values, factory test values, and partially measured values for each equipment (S2). This facility data is data including errors such as modeling errors.

  Therefore, the observation data (the magnitude and phase of the bus voltage) at each location of the power system are compared with the system state data (the magnitude and phase of the bus voltage) calculated at each location of the power system using the equipment data. The equipment data is corrected so that the system state data matches the system state data (S3).

  As described above, the observation data is data including a measurement error and a synchronization error, and the accuracy of the observation data is insufficient. Therefore, the estimation of the system state is performed using the equation (2) (S4). . In that case, the system state is estimated by using the equipment data or the corrected equipment data, the observed data (the magnitude and phase of the bus voltage) and the system state data (bus voltage) obtained by the calculation The magnitude and phase of the voltage in such a state that the deviation from the phase is minimized. This improves the accuracy of the system state data.

  Then, based on the magnitude and phase of the obtained voltage, the branch power of each node and the power flow state of the entire power system are obtained to grasp the system state (S5), and further, the observation cross section (condition for obtaining the observation data) The system analysis is performed from the system state data in (below) and the system analysis data is provided (S6).

JP-A-8-47174

  However, in the past, the accuracy of the equipment data has been improved by comparing and correcting the observation data of each part of the system and the calculation results (system state data) from the equipment data. The data is not always consistent as a whole. In addition, since the correction is based on temporary observation data in a certain observation section (under the condition for obtaining observation data), the data is not necessarily highly accurate in other observation sections. That is, the equipment data is not synchronized at the time when the system state data is desired.

  The system state data and system analysis data of a certain observation cross section estimated based on such equipment data include both errors of observation data and equipment data. Moreover, since the separation is difficult, there is a limit to improving the accuracy of the system analysis data.

  The objective of this invention is providing the equipment data estimation apparatus which can provide the equipment data with sufficient precision at the time of calculating | requiring system state data.

  The facility data estimation device according to the invention of claim 1 is an observation data measuring device that measures time-aligned observation data of each node of a power system, and a bus voltage of each node among the observation data measured by the observation data measuring device. Equation creation means for creating an equation with fixed values of magnitude / phase, active power, reactive power and equipment data as variables, and facility data calculation for computing the equipment data by solving the equation created by the equation creation means Means.

  The equipment data estimation device according to the invention of claim 2 is the state of the invention of claim 1, wherein the equation creating means creates a power flow equation as the equation, and the equipment data computing means is obtained by the power flow equation. And the equipment data in a state where the deviation from the observation data measured by the observation data measuring device is the smallest.

  The equipment data estimation device according to the invention of claim 3 is the invention according to claim 1, wherein the equation creating means creates a circuit equation for obtaining a current flowing into the node as the equation, and the equipment data calculating means comprises: The facility data is calculated in a state where the deviation between the inflow current obtained by the circuit equation and the inflow current measured by the observation data measuring device is minimized.

  According to the present invention, time-accurate high-precision observation data of each node of the power system is measured, and the bus voltage magnitude / phase, active power, and reactive power of each node are fixed values, and the equipment data is a variable. Since the equation is created and the equipment data is obtained by solving the equation, it is possible to obtain the synchronized equipment data at the time when the system state is desired. As a result, it is possible to provide equipment data at the time when changes due to aging, usage conditions, weather conditions, etc. of the equipment are taken into account, and it is expected to obtain equipment data at the time of observation reflecting the actual state of the entire power system.

The block block diagram of the equipment data estimation apparatus which concerns on embodiment of this invention. Explanatory drawing of the procedure which grasps | ascertains the system state of the electric power system of embodiment of this invention. Explanatory drawing of the procedure which grasps | ascertains the system state of the conventional electric power system.

  Embodiments of the present invention will be described below. FIG. 1 is a block configuration diagram of an equipment data estimation apparatus according to an embodiment of the present invention. The observation data measuring device 11 is installed in each node of the power system and detects an unknown amount of each node. For example, since the terminal voltage V and the active power P are known for the generator and the active power P and the reactive power Q are known for the load, the reactive power and phase, which are unknown quantities, are detected at the generator node. In the load node, the magnitude and phase of an unknown voltage are detected. The phase is a phase angle with respect to the reference voltage phase of the slack node.

  The observation data measuring device 11 defines a PMU (Phasor Measurement Unit) for directly observing the phase by defining the absolute time of the entire power network using distributed clock synchronization such as GPS (Global Positioning System) and high precision time protocol IEEE1588. It is installed.

  For example, IEEE 1588 is a standard protocol for synchronizing clocks connected via a multicast-compatible network such as Ethernet (registered trademark), and is a measurement system based on a precise time protocol with a synchronization accuracy of microseconds or less. By using such a high-accuracy measurement system, synchronous observation data of necessary locations with sufficient accuracy for grasping the state is acquired.

  That is, the observation data measuring device 11 measures the observation data by matching the phases detected by the respective parts of the power network with the absolute time. Observation data measured by the observation data measuring device 11 is taken in by the input processing unit 13 of the arithmetic and control device 12 and stored in the storage device 14.

  By using this observation data, it is possible to grasp the state of the grid directly and accurately (only with errors in the measurement system), so power flow calculation (state estimation calculation) using the simultaneous equations of equation (2) is unnecessary. It becomes.

  In the embodiment of the present invention, in order to obtain highly accurate facility data, conversely, the voltage vector v in equation (2) is fixed and the facility data is set as variable y, using the power flow equation in equation (3). The facility data y is obtained.

[Equation 3]
p = f (y) (3)
Therefore, the equation creating means 15 creates simultaneous equations for each node represented by the equation (3). That is, a simultaneous equation in which the magnitude and phase of the bus voltage at each node, the active power, and the reactive power are fixed values among the observation data measured by the observation data measuring device 11 and the facility data y is a variable is created.

The voltage vector v is a voltage vector composed of the magnitude and phase angle of the node voltage measured by the observation data measuring device 11, p is the effective power injected into the generator bus, and the effective injection into the bus for other buses. It is a specified value vector consisting of reactive power. Then, the facility data calculation means 16 solves the following optimization problem with the expression (4) as a constraint condition.

  However, wi is a weighting coefficient, zi = pi-fi (y), i = 1, 2,... N. n is the number of equations (= number of buses × 2), and zi is the deviation between the state calculated from the equipment data y and the observation data.

  As a result, the facility data y that matches the observation data (reflects the actual state of the entire system) is acquired. Observation data is data that takes into account changes due to operational status (age, usage rate, weather conditions, etc.), so equipment data also takes into account changes due to operational status (age, usage rate, weather conditions, etc.) Can be obtained.

  The facility data calculated by the facility data calculation means 15 is stored in the storage device 14 and is output to the output device 18 by the output processing unit 17 as necessary. The output device 18 is, for example, a display device or a printing device.

  In the above description, the tidal current equation is created as the equation and the equipment data is calculated. However, instead of the tidal equation, a circuit equation for obtaining the current flowing into the node may be created. The circuit equation is shown in equation (5).

[Equation 5]
I = YV (5)
I is a current flowing into the node, Y is equipment data, and V is a voltage vector measured with high accuracy. Also in this case, the facility data in a state where the deviation between the inflow current YV obtained by the circuit equation and the inflow current I measured by the observation data measuring device is minimized is calculated. (4) zi = Ii−Yi · Vi is applied to zi in the equation.

  Next, FIG. 2 is an explanatory diagram of a procedure for grasping the system state of the power system according to the embodiment of the present invention. Observation data measuring device 11 obtains observation data time-aligned with high accuracy at the nodes of the power system (S11). This observation data is the synchronized data of the necessary parts with sufficient accuracy for grasping the tidal current state.

  On the other hand, the equipment data is obtained as values such as design values, factory test values, and partially measured values for each equipment (S12). This facility data is data including errors such as modeling errors.

  Therefore, the equipment data is estimated and calculated by the equations (3) and (4) using the highly accurate observation data of each place in the power system (S13). Since this equipment data is estimated and calculated using synchronized observation data, it is data that takes into account changes due to operational conditions (age, utilization, weather conditions, etc.). It is data that can be corrected.

  As mentioned above, the observation data is data that can directly grasp the state of the system with high accuracy (only with measurement system errors), so tidal current calculation (state estimation calculation) using the simultaneous equations of (2) is unnecessary. (S14).

  Then, the branch power of each node and the power flow state of the entire power system are obtained from the observation data to grasp the system state (S15), and further from the system state data in the observation section (conditions for obtaining the observation data). System analysis is performed, and the system analysis data including accurate equipment data is provided (S16).

  In the embodiment of the present invention, by using a measurement system using distributed clock synchronization, state estimation calculation is not required, and the state of the system can be directly grasped with high accuracy. Moreover, since equipment data is calculated using highly accurate observation data, more precise system analysis data can be obtained.

DESCRIPTION OF SYMBOLS 11 ... Observation data measuring device, 12 ... Arithmetic control device, 13 ... Input processing part, 14 ... Memory | storage device, 15 ... Equation preparation means, 16 ... Equipment data calculation means, 17 ... Output processing part, 18 ... Output device

Claims (3)

An observation data measuring device that measures the observation data of each node of the power system,
An equation creating means for creating an equation having a fixed value for the magnitude and phase of the bus voltage of each node among the observation data measured by the observation data measuring device, active power, reactive power, and facility data as variables,
Facility data computing means for computing the equipment data by solving the equation created by the equation creating means;
An equipment data estimation device comprising:   The equation creating means creates a tidal current equation as the equation, and the equipment data calculating means has the smallest deviation between the state obtained by the tidal current equation and the observation data measured by the observation data measuring device. The equipment data estimation apparatus according to claim 1, wherein the equipment data in a state is calculated.   The equation creating means creates a circuit equation for obtaining the current flowing into the node as the equation, and the facility data calculating means is configured to obtain the inflow current obtained from the circuit equation and the inflow measured by the observation data measuring device. The equipment data estimation device according to claim 1, wherein the equipment data in a state in which a deviation from the current is the smallest is calculated.

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