JP2014023267A - Analysis device and analysis method for power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and stably analyze interactions between a distributed power supply system and a large-scale power system in the whole system where the distributed power supply system and a power system are interconnected.SOLUTION: A power system analysis device 1000 includes: a power system simulator 100 for simulating behaviors of a large-scale power system; a testing system 200 configured by an actual machine for simulating behaviors of a distributed power supply system to which a distributed power supply is connected; and an analysis controller 300 for equivalently connecting the power system simulator 100 and the testing system 200 that separately operate from each other. The analysis controller 300 includes: a power command generator 310 for setting a power to be input/output by a virtual power source 180 from/to a bus 150 in the power system simulator 100, on the basis of power achievement in the testing system 200; and a voltage command generator 320 for setting an output voltage of a voltage source circuit 210 in the testing system 200, on the basis of an AC voltage in the power system simulator 100.

Description

  The present invention relates to an analysis apparatus and an analysis method for a power system, and more particularly to a power system analysis for analyzing a mutual influence between a distributed power system and a large-scale power system.

  In recent years, a large number of small-scale distributed power systems such as photovoltaic power generation systems and storage battery systems tend to be connected to large-scale commercial power systems. For this reason, the necessity of the power system analysis for simulating the mutual influence between a distributed power supply system and a large-scale power system is increasing.

  In particular, in a distributed power source using natural energy such as a solar power generation system or a wind power generation system, there is a concern that the output fluctuates depending on natural conditions such as solar radiation and wind conditions. For this reason, it is necessary to analyze the influence of the output fluctuation in the distributed power system on the frequency fluctuation of the entire power system.

  For example, Japanese Patent Laying-Open No. 2005-137130 (Patent Document 1) describes a power system analysis device that enables connection simulation of two power systems. According to the power system analysis device of Patent Document 1, the divided first and second power systems are virtually connected via the current source of the first power system and the voltage source of the second power system. A configuration is disclosed. In particular, by extracting only the frequency component that satisfies the stability condition from the current of the second power system and giving it as the output command value of the current source of the first power system, the stable connection of the first and second power systems is achieved. It is described that it is possible to stably simulate one power system as a whole.

JP 2005-137130 A

  Generally, a power system simulator is used for analysis of a large-scale power system. Therefore, a method for analyzing the entire power system by linking and analyzing the power system simulator and a simulator based on a distributed power supply model is conceivable. However, it is not easy to match the distributed power supply model with the dynamic characteristics of the actual device, and it is difficult to increase the accuracy of the analysis.

  On the other hand, it is possible to configure a test device for a small-scale distributed power supply by using an actual machine. However, performing an actual machine test including interconnection with a large-scale power system is difficult in terms of installation location and cost. It is difficult from.

  A problem also arises when a power system analysis device is configured by combining a distributed power source test system composed of real machines and a power system simulator. Specifically, while the actual machine test system is a system that operates in real time, the power system simulator is a system that operates at predetermined time intervals to ensure the time required for simulation. The problem is how to link the two.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a distributed power system and a large-scale power system in an entire power system in which a distributed power system and a large-scale power system are interconnected. The object is to provide a configuration of a power system analysis apparatus for efficiently and stably analyzing a mutual influence between power systems.

  In one aspect of the present invention, an analysis apparatus for a power system includes a test system configured by an actual machine for simulating the behavior of a distributed power system to which a distributed power source is connected, and power for transmitting AC power of a predetermined frequency. A power system simulator for simulating system behavior and an analysis control unit for exchanging information between the test system and the power system simulator are provided. The power system simulator includes a virtual power source for simulated input / output of AC power having a predetermined frequency with respect to the power system. The test system includes an AC voltage source circuit connected to the distributed power supply system. The analysis control unit includes a first setting unit for setting input / output power by the virtual power source based on the actual power value in the distributed power system, and an AC voltage source circuit based on the AC voltage in the power system simulator. And a second setting unit for setting the voltage amplitude and frequency.

  In another aspect of the present invention, an analysis method for analyzing a power system in which a power system for transmitting power at a predetermined frequency and a distributed power system to which a distributed power source is connected is provided. A virtual power source in a power system simulator for simulating the behavior of the power system based on the acquired instantaneous power data and a step of acquiring the instantaneous power data in a test system configured with an actual machine for simulating the behavior The step of setting AC power of a predetermined frequency input / output from / to the power system and obtaining the AC voltage calculation result by the power system simulator under the state where the set AC power is input / output by the virtual power source And a step of setting the voltage amplitude and frequency of the AC voltage source circuit connected to the distributed power supply system based on the obtained AC voltage calculation result. And a flop.

  According to the present invention, it is possible to efficiently and stably analyze the mutual influence between the distributed power system and the large-scale power system in the entire power system in which the distributed power system and the large-scale power system are interconnected. .

It is a block diagram explaining the structure of the electric power system analyzer according to this Embodiment. It is a flowchart for demonstrating the analysis process sequence by the electric power grid | system analysis apparatus according to this Embodiment. It is a conceptual diagram for demonstrating transfer of the information between a test system | strain and an electric power system simulator. It is a block diagram explaining the structure of the electric power system analyzer according to the modification of this Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

  FIG. 1 is a block diagram illustrating a configuration of a power system analysis apparatus according to an embodiment of the present invention.

  Referring to FIG. 1, power system analysis apparatus 1000 according to the embodiment of the present invention shows power system simulator 100 for simulating the behavior of a large-scale power system and the behavior of a distributed power system to which a distributed power source is connected. It includes a test system 200 configured with real machines for simulation, and an electric power system simulator 100 and an analysis control unit 300 for exchanging information between the test systems 200.

  The power system simulator 100 is configured to simulate the behavior of a power system (a power transmission system by a power company) for transmitting AC power having a predetermined system frequency (50 Hz or 60 Hz) using a known simulator. The power system simulated by the power system simulator 100 includes a generator 110, a transformer 120, buses 130 and 150, a power transmission line 140, a virtual generator 180, and a voltage detector 190. The virtual generator 180 is configured to input / output AC power having a system frequency according to a command from the analysis control unit 300 to / from the bus 150 assumed to be connected to the distributed power supply system. The virtual generator 180 is an example of a “virtual power source”.

  For example, the power system simulator 100 models each element of the power system by a mathematical expression, and solves the mathematical expression by a computer, so that the voltage absolute value of the alternating voltage at the bus 150 at a constant period of the sampling time interval Δt | Calculate V | and voltage phase δ.

  Or the electric power system simulator 100 may be comprised by the analog simulator which connected the equivalent electric circuit of each element. Also in this case, the voltage detector 190 can detect the voltage absolute value | V | and the voltage phase δ of the AC voltage of the bus 150 at a predetermined constant period corresponding to Δt.

  The test system 200 is an experimental power system composed of actual devices. The test system 200 includes a three-phase AC power line 205, a three-phase AC voltage source circuit 210, a photovoltaic power generation system 220 that is a “distributed power source”, a load 230, and a detector 240. The test system 200 may further be provided with a storage battery 250. The absolute value and frequency of the output voltage of the voltage source circuit 210 are controlled according to a command from the analysis control unit 300.

  The detector 240 is configured by a sensor for detecting data related to the power performance of the power line 205. For example, the detector 240 measures the instantaneous voltage values va, vb, vc and the instantaneous current values ia, ib, ic of the power line 205 of the test system 200.

  In the test system 200, the output power of the photovoltaic power generation system 220, which is a distributed power supply, is supplied to the load 230 and the storage battery 250. Therefore, the instantaneous power of the power line 205 changes due to output fluctuations of the distributed power supply. This power change can be detected by the analysis control unit 300 based on the output of the detector 240.

  Analysis control unit 300 includes a power command generation unit 310 and a voltage command generation unit 320. The power command generation unit 310 inputs / outputs power (system power AC power) of the virtual generator 180 in the power system simulator 100 based on the actual power (instantaneous power value) in the test system 200 detected by the detector 240. Set. As a result, a state where AC power equivalent to input / output power in the test system (distributed power system) 200 is input / output to / from the bus 150 can be formed, so that the test system 200 is equivalently connected to the bus 150. And the electric power system simulator 100 can be operated.

  The power system simulator 100 calculates the voltage absolute value | V | and the voltage phase δ of the bus 150 when the AC power set by the power command generator 310 is input to and output from the bus 150. Thereby, the influence of the output fluctuation in the distributed power supply on the AC voltage fluctuation of the bus 150 is simulated.

  Voltage command generator 320 sets the output voltage of voltage source circuit 210 in test system 200 based on the AC voltage of bus 150 in power system simulator 100. That is, since the output voltage of the voltage source circuit 210 becomes equivalent to the AC voltage of the bus 150, the test system 200 can be operated by creating a state where the power line 205 is equivalently connected to the bus 150.

  In this way, the analysis control unit 300 operates to equivalently connect both operating separately by exchanging information between the power system simulator 100 and the test system 200. The power command generation unit 310 corresponds to a “first setting unit”, and the voltage command generation unit 320 corresponds to a “second setting unit”.

  FIG. 2 shows an analysis processing procedure by the power system analysis apparatus according to the present embodiment. The flowchart shown in FIG. 3 shows a series of processing procedures that are repeatedly executed at predetermined sample time intervals Δt.

  Referring to FIG. 2, in step S100, analysis control unit 300 performs data relating to instantaneous power (specifically, instantaneous voltage values va, vb, vc and instantaneous current values ia, ib) of power line 205 of test system 200. , Ic) is obtained by sampling the output of the detector 240.

  In step S110, analysis control unit 300 calculates instantaneous active power P (t) and instantaneous reactive power Q (t) in test system 200 in accordance with the following equations (1) and (2).

  Alternatively, the power command generation unit 310 may calculate the instantaneous active power P (t) and the instantaneous reactive power Q (t) in the test system 200 according to the following formulas (3) to (8) involving coordinate conversion. .

  The calculated instantaneous active power P (t) and instantaneous reactive power Q (t) are obtained when the distributed power system simulated by the test system 200 and the power system simulated by the power system simulator 100 are connected. Power supplied from the distributed power system to the power system (P (t), Q (t)> 0) or power supplied from the power system to the distributed power system (P (t), Q (t) <0) Is shown. When the output of the distributed power supply fluctuates, the instantaneous active power P (t) and the instantaneous reactive power Q (t) of the power line 205 change.

  In step S120, analysis control unit 300 sets input / output power by virtual generator 180 according to instantaneous active power P (t) and instantaneous reactive power Q (t) calculated in step S110. Thus, the function of the power command generation unit 310 of FIG. 1 is realized by the processing of steps S110 to S120.

  In the power system simulator 100, the AC voltage of the bus after the elapse of the sample time interval Δt under the condition that the virtual generator 180 inputs and outputs the AC power set in step S120 to the bus 150 is calculated. For example, the absolute voltage value | V | and voltage phase δ of the AC voltage of the bus 150 are calculated.

  Thus, in the power system simulator 100, the output fluctuation in the test system 200 (distributed power supply system) can be caused to act as a power fluctuation disturbance for the bus 150 by the virtual generator 180 (virtual power source). As a result, it is possible to analyze the influence of the output fluctuation in the distributed power supply system on the voltage fluctuation (voltage absolute value and phase) in the power system.

In step S130, analysis control unit 300 obtains voltage absolute value | V | and voltage phase δ of the AC voltage of bus 150 calculated by power system simulator 100 as described above. Further, the analysis control unit 300, based on the voltage absolute value | V | and the voltage phase δ of the AC voltage calculated by the power system simulator 100 in step S140, represents the frequency variation amount according to the following equation (9). A frequency deviation Δω ₀ is calculated.

In Expression (9), δ (t−1) is the voltage phase δ calculated last time (that is, before Δt), and δ (t) is the voltage phase δ calculated this time. The angular frequency deviation Δω ₀ indicates a deviation from the standard angular frequency corresponding to a predetermined system frequency (50 Hz or 60 Hz), and corresponds to a frequency variation in the power system.

Based on the voltage absolute value | V | based on the calculation result of the power system simulator 100 and the angular frequency deviation Δω ₀ in step S150, the analysis control unit 300 performs the test system 200 according to the following equations (10) to (12). The output voltage of the voltage source circuit 210 is set.

  Thereby, it is possible to analyze the influence of the voltage fluctuation (frequency fluctuation) of the power system caused by the output fluctuation of the distributed power supply on the test system 200 (distributed power supply system). As described above, the function of the voltage command generation unit 320 of FIG. 1 is realized by the processing of steps S130 to S150.

  Referring to FIG. 3, in the power system analysis apparatus according to the present embodiment, the analysis control unit 300 causes the power fluctuation in the test system 200 (distributed power supply system) caused by the output fluctuation of the distributed power supply to the virtual generator 180 ( This is reflected as a power fluctuation disturbance in the power system simulator 100 by the virtual power source. Furthermore, voltage fluctuations (particularly frequency fluctuations) generated in the power system due to this power fluctuation disturbance can be reflected in the test system 200.

  As described above, in the power system analysis apparatus according to the present embodiment, the power system and the distributed power source are combined by combining the actual machine test system for simulating the distributed power system and the simulator for simulating the large-scale power system. Mutual effects between systems can be analyzed. Furthermore, in the entire power system where a distributed power system and a large-scale power system are interconnected, reflecting the mutual influence between the two systems, the effects of fluctuations in the output of the distributed power source on the entire system, Can be analyzed.

  In the power system analysis device according to the present embodiment, instantaneous value data in the test system 200 configured with an actual machine is converted into AC power information of the system frequency, and the power system operates at a constant time interval (Δt). By transmitting to the simulator 100, the power system simulator 100 and the test system 200 are equivalently connected. Thereby, the analysis of the whole electric power grid | system can be performed stably, without producing the divergence of the voltage and electric current pointed out by patent document 1. FIG.

  In addition, when simulating the entire power system and distributed power system in real time, there is concern about an increase in hardware load (equipment scale) or software load (computer load). According to the present embodiment, which combines a power system simulator that executes time step calculation and a test system of an actual machine, analysis of the entire power system can be executed efficiently.

  As a modification of the power system analysis device, as shown in FIG. 4, a “virtual power source” provided in the power system simulator 100 is replaced with a virtual current source 185 instead of the virtual generator 180 (FIG. 1). It is also possible to use it. In this case, power command generation unit 310 calculates current absolute value | I | and current phase (current phase difference with respect to voltage) φ based on instantaneous current value and instantaneous voltage value detected by detector 240. To do. Further, power command generation unit 310 performs virtual operation in power system simulator 100 such that an AC current at the system frequency is input / output to / from bus 150 according to the calculated absolute current value | I | and current phase φ. A command for the current source 185 is generated.

  Similarly, in step S110 of FIG. 2, the absolute current value | I | and the current phase φ in the test system 200 are calculated, and in step S120, the absolute current value input and output by the virtual current source 185 in the power system simulator 100 is calculated. The value and current phase are set.

  Even in this case, as in the power system analysis apparatus shown in FIG. 1, in the entire power system in which the distributed power system and the large-scale power system are connected, the mutual influence between both systems is reflected. It is possible to analyze the influence (especially frequency fluctuation) of the output fluctuation of the distributed power source on the entire system.

  In this embodiment, the solar cell system is exemplified as the distributed power source connected to the test system 200 of the actual machine. However, any power source can be applied to the actual machine as long as it is a distributed power source linked to the power system. it can. In addition, the power system simulator 100 can be configured by any known simulator.

  According to the present embodiment, it is possible to analyze the influence of fluctuations in the output of the distributed power supply on the entire power system interconnecting the distributed power supply system and the power system. Therefore, in the power system analysis according to the present embodiment, a distributed power system connected to a distributed power source configured to generate power by natural energy, which is likely to cause output fluctuations, is suitable as an analysis target.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 Power System Simulator, 110 Generator, 120 Transformer, 130, 150 Bus, 140 Transmission Line, 180 Virtual Generator, 185 Virtual Current Source, 190 Voltage Detector, 200 Test System, 205 Power Line, 210 Voltage Source Circuit, 220 Solar power generation system, 230 load, 240 detector, 250 storage battery, 300 analysis control unit, 310 power command generation unit, 320 voltage command generation unit, 1000 power system analysis device.

Claims (6)

A test system composed of actual machines for simulating the behavior of the distributed power supply system to which the distributed power supply is connected;
A power system simulator for simulating the behavior of the power system for transmitting AC power of a predetermined frequency;
An analysis control unit for transferring information between the test system and the power system simulator,
The power system simulator is
A virtual power source for simulating input / output of AC power of the predetermined frequency to the power system,
The test system is
An AC voltage source circuit connected to the distributed power supply system,
The analysis control unit
A first setting unit for setting input / output power by the virtual power source based on the actual power value in the distributed power supply system;
And a second setting unit for setting a voltage amplitude and a frequency of the AC voltage source circuit based on an AC voltage in the power system simulator. The power fluctuation simulator calculates a voltage amplitude and a voltage phase of an AC voltage in the power system every predetermined time interval,
The power system analysis device according to claim 1, wherein the second setting unit sets the frequency of the AC voltage source circuit according to the calculated change amount of the voltage phase. The virtual power source is constituted by a virtual generator connected to the power system,
The second setting unit sets instantaneous active power and instantaneous reactive power input and output by the virtual generator based on instantaneous current values and instantaneous voltage values in the distributed power supply system. The power system analysis device described. The virtual power source is constituted by a virtual current source connected to the power system,
The said 2nd setting part sets the amplitude and phase of the electric current input / output by the said virtual current source based on the electric current instantaneous value and the voltage instantaneous value in the said distributed power supply system. Power system analyzer.   5. The power system analysis device according to claim 1, wherein the distributed power source is configured to generate power using natural energy. An analysis method of a power system in which a power system for transmitting power of a predetermined frequency and a distributed power system connected to a distributed power source are interconnected,
Obtaining instantaneous power data in a test system composed of actual machines for simulating the behavior of the distributed power system; and
Setting the AC power of the predetermined frequency input / output from / to a power system from a virtual power source in a power system simulator for simulating the behavior of the power system based on the acquired instantaneous power data; ,
Obtaining a calculation result of the AC voltage by the power system simulator under a state where the set AC power is input and output by the virtual power source; and
A method for analyzing a power system, comprising: setting a voltage amplitude and a frequency of an AC voltage source circuit connected to the distributed power supply system based on the obtained calculation result of the AC voltage.

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