JP2000245061A - Electric power system analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a hybrid electric power system analyzer suitable for analyzing an electric power system having a shorter state change than the analysis step time of a digital simulator. SOLUTION: In this electric power system analyzer, an analog simulator 12 is equipped with an analog simulation means 22 of an electric power system PS2, and a subsidiary power source 32 connected via an impedance element 23 of a linkage with an electric power system PS1 as a simulation object of a digital simulator 11, which is equipped with a digital simulation means 21 for analyzing the electric power system PS1 and a subsidisry power source 31 connected via an impedance element 23 of a linkage with the electric power system PS2. A command which makes the power source 31 generate electric quantity at the connection point of the analog simulation means and the impedance element and makes the power source 32 generate electric quantity at the connection point of the digital simulation means and the impedance element is outputted from an interface circuit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power system analysis device combining a digital simulator and an analog simulator.

[0002]

2. Description of the Related Art Conventionally, as a power system analysis device,
An analog simulator in which an actual power system is configured by a miniature model has been used. However, such an analog power system analyzer has a large effect of loss because the simulated voltage used is lower than that of an actual power system,
For example, there is a problem that the state of the transient transient oscillation of the voltage or the current does not match the actual phenomenon. In addition, when simulating a large-scale power system, there is a problem that the size of the analysis device is increased because the power transmission and transformation equipment is simulated by the analog simulator.

On the other hand, with the speeding-up of microprocessors and the development of software for analyzing power systems, highly accurate analysis by digital simulators has recently been performed. In particular, since a digital simulator simulates a power system by digital operation, it can be constituted by a computer such as a work station for inputting data and an analysis engine including a microprocessor, so that the apparatus can be made compact.

Therefore, in order to reduce the scale of the analog simulator and to cope with a change in the system configuration, a power system analysis simulator system combined with a digital simulator has been proposed (Japanese Unexamined Patent Publication No. Hei. No. 256529). According to this, power devices such as generators, transformers, loads, and control models,
An analog simulator that simulates a relay model in analog and a digital simulator that simulates the part of network calculation are connected via a D / AA / D converter to shorten the convergence calculation of the network calculation. In addition, the size of the analog simulator is suppressed, and changes in the system configuration can be relatively easily handled.

[0005]

However, in the digital simulator, there is a problem that a phenomenon having a time constant smaller than the analysis step time, which is the analysis operation cycle, cannot be analyzed. For example, in a power system that includes a self-excited semiconductor power converter, high-speed switching is performed by the semiconductor of the converter, and therefore, analysis of such a power system requires a short analysis step time of 5 to 10 μs. . However, at present, the analysis step of a general real-time digital simulator is about 50 to 100 μs, so that there is a problem that accurate analysis cannot be performed.

Therefore, a power system that requires a small analysis step time is simulated by an analog simulator, and a portion where there is no problem even if the analysis step time is long is simulated by a real-time digital simulator, and these are combined or combined. Thus, a hybrid power system analyzer that analyzes a power system is conceivable, but such a hybrid power system analyzer has not been considered in the past.

An object of the present invention is to realize a hybrid power system analysis apparatus suitable for analyzing a power system with a state change shorter than the analysis step time of a digital simulator. In particular, it is an object to appropriately combine an analog simulator and a digital simulator.

[0008]

The above object can be attained by the following means. First, an analog simulator for analyzing a part of the power system by analog simulation and a digital simulator for analyzing the remaining part of the power system by digital simulation are basically provided. An analog simulating means for simulating a system by analog simulating, and a part connected to a part corresponding to a link system of a power system to be simulated by a digital simulator via an impedance element simulating at least a part of the link system. The digital simulator comprises: a digital operation means for digitally simulating and analyzing the power system to be simulated; and a part corresponding to a link system between the power system to be simulated by the analog simulator. Data through an impedance element equivalent to the impedance element. The second result and a sub power supply rewriting Te, a command to generate electricity quantity corresponding to the detected value of the electric quantity at the connection point of the impedance element and the analog simulator means to the second slave power supply,
Digital simulation means and interface means for outputting a command for generating an electric quantity corresponding to a detected value of the electric quantity at the connection point of the impedance element to the first dependent power supply are provided.

[0009] The impedance element is a first element.
And a transfer function taking into account a transfer time delay from the detection of the amount of electric power commanded to the second dependent power supply to the input thereof is set to a value that satisfies a stability condition according to the Nyquist discrimination method. As a result, it is possible to suppress the analysis instability due to the influence of the transmission delay time of the electric quantity at the link point transmitted and received between the analog simulator and the digital simulator.

In addition, the voltage of each part is determined depending on whether or not a transmission time delay from detection of an electric quantity commanded to the first and second dependent power supplies to input of the impedance element is taken into consideration. By setting the current to a value that suppresses the error obtained by comparing the fundamental components of the current, it is possible to suppress the error in the analysis result due to the influence of the transmission delay time.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a main part of a hybrid power system analysis device according to one embodiment, and FIG. 2 is a schematic configuration diagram of the whole. FIG. 3 shows a power system model to be analyzed to which the embodiment of FIG. 1 is applied.

As shown in FIG. 2, the hybrid power system analysis device includes a digital simulator (RDS) 11 for executing real-time analysis and an analog simulator (A).
NS) 12, an interface circuit (INF) 13, and an input / output device (WS) 14. The digital simulator 11 is configured to include digital simulation means including an analysis engine including a microprocessor. The analog simulator 12 performs analog simulation analysis on a part of a power system as an analysis target, and is configured to include analog simulation means that simulates the power system to be analyzed with a miniature model. The interface circuit 13 is connected to each of the digital simulator 11, the analog simulator 12, and the input / output device 14, and exchanges data between them. The input / output device 14 is configured using a computer, and performs input / output of input data, analysis conditions, display of analysis results, and the like to the digital simulator 11, the analog simulator 12, and the interface circuit 13.

As shown in FIG. 3, the power system model to be analyzed includes a power system divided into two power systems PS1 and PS2, and these two power systems are connected via an impedance element Ze. I do. Here, the power system P
S2 is a power system that includes transmission and transformation equipment such as power electronics equipment. That is, in power electronics devices and the like, since the switching frequency is increasing, the state change occurs in a very short time. In order to analyze a state change of a system including such a power electronic device or the like, a small analysis step time (for example, 50 μs or less) is required. on the other hand,
The power system PS1 is assumed to be a power system configured with transmission and transformation equipment having a relatively long analysis step (for example, 50 μs or more).

Then, as shown in FIG.
2 is analyzed by the analog simulator 12, and the power system PS1 is analyzed by the digital simulator 11. Here, one of the points relating to the characteristic portion of the present invention is that the analog simulator 12 and the digital simulator 11 use the common impedance element Ze,
The voltage or current across the impedance element Ze is
The point is that both simulators are connected so that they can be exchanged. Here, the impedance element Ze corresponds to the impedance of the transmission / transformation equipment of the system that connects the power systems PS1 and PS2, that is, the system that forms the connection part, and simulates the impedance of all or at least a part of the connection part. Is what you do. Here, the voltages Vn1 and Vn2 across the common impedance element Ze are
When it is determined including the phase information, the exchange of power between the power systems PS1 and PS2 is uniquely determined. Therefore, the subordinate power supply having the impedance element Ze common to the power system PS2 and the system voltage Vn1 of the power system PS1 simulated by the digital simulator 11 is analog-simulated, and the power system P2
The impedance element Ze common to S1 and the system voltage Vn of the power system PS2 simulated by the analog simulator 12
By digitally simulating the sub power supply having the power supply 2, a hybrid power system analysis device combining the two simulators shown in FIG. 1 can be realized.

That is, as shown in FIG. 1, the analog simulator 12 has analog simulating means 22 for simulating the power system PS2 in an analog manner.
One end of an impedance element 23 that simulates impedance constituting at least a part of the link system is connected to a portion corresponding to a link point with 1, and a dependent power supply 32 is connected to the other end of the impedance element 23. It is configured. Also, the voltage V on the self-end side of the impedance element 23 is
n2 is detected by the voltage detector 36 and output to the interface circuit 13.

On the other hand, the digital simulator 11 has digital simulating means 21 for simulating the power system PS1 by digital operation, and the impedance element 23 is provided at a portion corresponding to a link point with the power system PS2.
One end of an impedance element 23 equivalent to the above is connected, and the other end of the impedance element 23 is connected to a dependent power supply 31. However, the configuration of the illustrated digital simulator 11 schematically represents a concept, and is actually configured by a digital processor.
That is, the impedance element 23 is set as an operation constant, the dependent power supply 31 is simulated by an arithmetic expression or the like, and system data at one end of the impedance element 23 is shared as data of a portion corresponding to a link point of the digital simulation means 21. It has become. The impedance element 23
The calculation data of the voltage Vn1 on its own end is conceptually detected by the voltage detector 35 and output to the interface circuit 13.

The interface circuit 13 includes command generation circuits 33 and 34. Command creation circuit 3
Reference numeral 4 denotes a detection voltage Vn2 output from the voltage detector 36 of the analog simulator 12, and the slave power supply 3 of the digital simulator 11
1 as a command value to adjust the output voltage Vn2. Similarly, the command creation circuit 33 takes in the detection voltage Vn1 sent from the voltage detector 35 of the digital simulator 11, sends it as a command value to the sub power supply 32 of the analog simulator 12 as it is after one analysis step, and outputs the output voltage. Vn1 is adjusted.

As described above, according to the configuration of FIG. 1, the analysis data at the link point between the analog simulator 12 and the digital simulator 11 is supplied via the common impedance element and mutually dependent power supplies 31 and 32. As described above, since the two simulators are combined, it is possible to realize a hybrid power system analysis device utilizing the characteristics of each simulator. In particular, if the transmission delay time of the command value due to the sampling time or the like is sufficiently small compared to the movement of the phenomenon to be analyzed, the power can be accurately calculated by the device combining the analog simulator 12 and the digital simulator 11 as shown in FIG. Systematic analysis can be performed.

However, in the case of FIG.
If the delay time is long between the detection of 1, Vn2 and the transmission of the command value to each sub power supply, the analysis may become unstable or the error of the analysis result may increase. An embodiment of the present invention capable of solving such a problem will be described with reference to FIG.

The power systems PS1 and PS2 are equivalently connected to voltage sources Vs1 and Vs1 having internal impedances Z1 and Z2, respectively.
When it is replaced with Vs2, it becomes as shown in FIG. Further, the common impedance element Ze in FIG. 1 is assumed to be Ze ′. Here, a delay time from when a voltage value is detected between the digital simulator 11 and the analog simulator 12 to when a command value is transmitted to the respective dependent voltage sources 31 and 32 is defined as τ. First, a method for suppressing the analysis instability due to the influence of the delay time will be described.

A signal consisting of Vs1 and Vs2 is input and
When FIG. 1 is represented by a block diagram using Vn1 as an output, the result is as shown in FIG. 5, and the open-loop transfer function Go (s) is represented by Expression 1.

[0022]

(Equation 1)

Here, by applying the Nyquist stability discrimination method to Equation 1, a condition for stabilizing the analysis of FIG. 4 is derived. That is, in Equation 1, s = jω, and ω =
Open loop transfer function Go when varied in the range of 0 to ∞
As the trajectory on the complex plane of (s) crosses the (-1, 0) point while looking to the left when crossing the negative real axis, Z1,
Z2 and Ze 'are set. This suppresses analysis instability between the digital simulator 11 and the analog simulator 12 due to the delay time τ required from the detection of the voltage value to the transmission of the command value to the dependent voltage sources 31 and 32. Can be.

Next, a method for suppressing an error in the analysis result due to the influence of the delay time will be described. In FIG. 4, after a voltage value is detected between the digital simulator 11 and the analog simulator 12, the command value is changed to the dependent voltage source 31,
32, when the delay time τ required to be transmitted to the simulator 32 is ignored and when the delay time τ is considered.
By comparing the fundamental wave components of the currents In1 and In2 flowing through the impedance elements 24, respectively, the following equation (2) is obtained.

[0025]

(Equation 2)

Here, Z1, Z
2, Ze 'may be set. That is, the power system PS
The digital simulator 11 and the analog simulator 12 are controlled by adjusting the separation point of the impedance element 24 that simulates the impedance of the link system between the PS1 and PS2, that is, the length of the power transmission line and whether the power transmission device belongs to PS1 or PS2. Between the detection of the voltage value and the transmission of the command value to the dependent voltage source due to the delay time.

As described above, by setting Z1, Z2, and Ze 'so as to satisfy the conditions given by the equations (1) and (2), the real-time hybrid power system analyzer as shown in FIG. Analysis becomes possible. Therefore, in order to analyze the power system shown in FIG. 3 by the power system analysis device shown in FIG. 1, the power systems PS1 and PS2 are equivalently converted into internal impedances Z1 and Z as shown in FIG.
Assuming that the voltage source has a value of 2, the value Ze ′ of the impedance element 24 is adjusted in advance so as to satisfy the conditions given by Equations (1) and (2) before performing the analysis to separate the common impedance of the linked system. Must be set.

FIG. 6 shows a basic configuration of a power system analysis apparatus according to another embodiment in which the present invention is applied to the power system model of FIG. 6, components having the same functional configuration as in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The difference from FIG. 1 is that the detected electric quantity at the link point of the digital simulator 11 is changed to a current, and the dependent power supply of the analog simulator 12 is replaced with a dependent current source 62 in accordance with this. Therefore, the command value generation circuit 37 of the interface circuit 13 outputs the detected current at the link point of the digital simulator 11 detected by the current detector 612 to the dependent current source 62 as a command value as it is after one analysis step.

Here, in the case of the power system analyzing apparatus shown in FIG. 6, similarly to the case of FIG. 1, after the voltage value and the current value are detected, the corresponding subordinate voltage source 31 and subordinate current source 62
It is necessary to suppress the influence of the delay time required until the command value is transmitted to the controller. Therefore, as shown in FIG.
Between the detection of the voltage value and the current value and the transmission of the command value to the subordinate voltage source 31 and the subordinate current source 62 is defined as τ, and the power systems PS1 and PS2 are equivalently equivalent to the internal impedance Z1. , Z2. This is represented by a block diagram as shown in FIG.
The open-loop transfer function Go (s) is expressed by Equation 3. Here, by applying the Nyquist stability determination method to Equation 3,
The condition for stabilizing FIG. 7 is derived. In FIG. 7, the delay time τ required between the detection of the voltage value and the current value between the digital simulator 11 and the analog simulator 12 until the command value is transmitted to the dependent voltage source 31 and the dependent current source 62 is ignored. By comparing the voltages Vn1 and Vn2 of each simulator and the fundamental components of the currents In1 and In2 flowing through the impedance element 24, respectively, in the case where the simulation is performed and the case where the simulation is considered, Expression 4 is obtained.

[0030]

(Equation 3)

[0031]

(Equation 4)

By setting Z1, Z2, and Ze 'so as to satisfy the conditions given by Equations 3 and 4,
Digital simulator 11 and analog simulator 1
The analysis instability and the error of the analysis result due to the influence of the transmission delay time of the command value between the two can be suppressed, and the analysis by the real-time power system analysis device shown in FIG. 7 becomes possible. Therefore, in order to analyze the power system shown in FIG. 3 by the real-time power system analysis device shown in FIG. 6, the power system PS1 to be simulated by the digital simulator 11 and the power system PS2 to be simulated by the analog simulator 12 are to be analyzed. Are considered as voltage sources Vs1 and Vs2 equivalently having internal impedances Z1 and Z2, respectively, the value Ze ′ of the impedance element 24 becomes
It is necessary to adjust the division of the linked part before the analysis so as to satisfy the condition given by.

Although each of the above embodiments has been described as a single-phase circuit, it is apparent that a three-phase circuit can be similarly handled.

In this embodiment, only the case where the analog simulator and the digital simulator are connected is shown. However, the case where the analog simulator and the analog simulator are connected, and the case where the digital simulator is used.
The case where the digital simulator and the digital simulator are combined can be handled in the same manner.

[0035]

As described above, according to the present invention,
A hybrid power system analysis device suitable for analyzing a power system with a state change shorter than the analysis step time of the digital simulator can be realized. In particular, the analog simulator and the digital simulator can be appropriately combined.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a power system analysis device according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a power system analysis device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a power system model to which the embodiment of FIG. 1 is applied.

FIG. 4 is a diagram when the power system to be simulated by the power system analysis device of the embodiment in FIG. 1 is replaced with an equivalent voltage source having an internal impedance.

FIG. 5 is a diagram showing the power system analysis device shown in FIG. 4 in a block diagram of a transfer function.

FIG. 6 is a basic configuration diagram of a main part according to a power system analysis device of one embodiment of the present invention.

7 is a diagram when the power system to be simulated by the power system analysis device of the embodiment of FIG. 6 is replaced with an equivalent voltage source having an internal impedance.

8 is a diagram showing a block diagram of a transfer function of the power system analysis device shown in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Digital simulator 12 Analog simulator 13 Interface circuit 14 Input / output device 21 Digital simulation means 22 Analog simulation means 23, 24 Impedance element 31, 32 Dependent voltage source 33, 34, 37 Command value creation circuit 35, 36 Voltage detector 61 Current detection Unit 62 Dependent current sources PS1, PS2 Power system

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroo Konishi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takayoshi Sano 6-19, Tsukiji, Chuo-ku, Tokyo No. 20 F-term (Reference) in Technology Research Institute of Japan 5G066 AA03 AE09 AE10

Claims (3)

[Claims] 1. An analog simulator for analyzing a part of a power system by analog simulation, and a digital simulator for analyzing the remaining part of the power system by digital simulation, wherein the analog simulator has its own power to be simulated. An analog simulation means for analogly simulating and analyzing a system, and a part corresponding to a cooperative system of a power system to be simulated by the digital simulator, which is connected via an impedance element simulating at least a part of the cooperative system. First
The digital simulator corresponds to a link system between a digital operation unit that digitally simulates and analyzes a power system to be simulated by itself and a power system to be simulated by the analog simulator. A second sub power supply for rewriting the data of the part via an impedance element equivalent to the impedance element; and an electric power corresponding to a detected value of an electric quantity at a connection point between the analog simulation means and the impedance element. Interface means for outputting a command to generate a quantity in the second dependent power supply and a command to generate a quantity of electricity corresponding to a detected value of the quantity of electricity at the connection point between the digital simulation means and the impedance element in the first dependent power supply And the impedance element is configured to receive a command from a first and a second dependent power supply. A power system analysis device, wherein a transfer function taking into account a transfer time delay from the detection of an air volume to an input is set to a value that satisfies a stability condition according to the Nyquist discrimination method. 2. An analog simulator for analyzing a part of an electric power system by analog simulation, and a digital simulator for analyzing the remaining part of the electric power system by digital simulation, wherein the analog simulator has its own power to be simulated. An analog simulation means for analogly simulating and analyzing a system, and a part corresponding to a cooperative system of a power system to be simulated by the digital simulator, which is connected via an impedance element simulating at least a part of the cooperative system. First
The digital simulator corresponds to a link system between a digital operation unit that digitally simulates and analyzes a power system to be simulated by itself and a power system to be simulated by the analog simulator. A second sub power supply for rewriting the data of the part via an impedance element equivalent to the impedance element; and an electric power corresponding to a detected value of an electric quantity at a connection point between the analog simulation means and the impedance element. Interface means for outputting a command to generate a quantity in the second dependent power supply and a command to generate a quantity of electricity corresponding to a detected value of the quantity of electricity at the connection point between the digital simulation means and the impedance element in the first dependent power supply And the impedance element is configured to receive a command from a first and a second dependent power supply. It must be set to a value that suppresses the error obtained by comparing the fundamental wave components of the voltage and current of each part when the transmission time delay from the detection of the air volume to the input is considered and when it is not considered A power system analyzer characterized by the above-mentioned. 3. The power system analysis device according to claim 1, wherein the electric quantity is a voltage or a current.