JP6701802B2 - Power system simulator, interface, and program - Google Patents

Description

  The present invention relates to a power system simulator, an interface, and a program.

  As one form of the power system simulator that analyzes the state of the power system, some elements of the power system (for example, power lines, devices that operate at high speed such as circuit breakers, and devices that saturate like transformers) are used. A power system simulator is known that includes an analog simulator that simulates and a digital simulator that simulates the remaining elements of the power system.

  This kind of power system simulator requires an interface or a connecting device for connecting an analog simulator and a digital simulator. For example, the BERGERON coupling type interface simulates both ends of a transmission line that can be regarded as a distributed constant line as shown in FIG. 1 on the analog side and the digital side, as shown in FIG. An analog simulator and a digital simulator are combined by detecting with a voltage detector and a current detector, calculating a detected value, and returning it as an equivalent current source. (For example, patent document 1, non-patent document 1).

JP 2004-9689 A

Hiroto Inabe, Hiroo Konishi, "Hybrid Real-Time Simulator: Combined Analysis Method of Analog Simulator and Digital Simulator", The Institute of Electrical Engineers of Japan, 2002, Vol. 122, No. 5, p.

  However, the current detector has a considerable influence on the analog side circuit, which may cause an error in the simulation result. Further, a current detector capable of accurately detecting a current from direct current to high frequency requires high cost.

  The present invention has been made in view of such a problem, and an object thereof is to provide a power system simulator that can obtain accurate simulation results at low cost.

  One of the means for solving the above problems is a digital simulator simulating a first power system, an analog simulator simulating a second power system connected to the first power system through an electric wire, and the digital simulator. A first current source connected to the simulator, a first current source connected in parallel with the first current source so that a current from the digital simulator and a current from the first current source flow, and a first impedance indicating a characteristic impedance of the electric wire; A resistor, a second current source connected to the analog simulator, and a second current source connected in parallel so that the current from the analog simulator and the current from the second current source flow, and the characteristic impedance The second resistance shown, the output current and the output voltage of the first electric power system at the second time before the first time calculated by the digital simulator, and the output at the second time output from the analog simulator. A first controller that controls the first current source based on an output voltage of a second power system, and the second current source based on an output current and an output voltage of the first power system at the second time. A second control device for controlling the.

  In addition, the problem disclosed by the present application and the solution to the problem will be clarified by the description of the mode for carrying out the invention, the description of the drawings, and the like.

  According to the present invention, it is possible to provide a power system simulator that can obtain accurate simulation results at low cost.

It is a figure which shows an example of the electric power system simulated by the electric power system simulator which concerns on this embodiment. It is a figure which shows an example of the equivalent circuit model of the electric power system of FIG. It is a figure which shows the structure of the electric power system simulator which concerns on this embodiment. FIG. 4 is a block diagram showing a signal operation related to Expression b in FIG. 3. It is a figure which shows an example of a known electric power system simulator.

  At least the following matters will be made clear by the present specification and the description of the accompanying drawings.

  The power system simulator according to the present embodiment will be described with reference to FIGS. 1 to 4.

[Power system to be simulated]
FIG. 1 shows an example of a power system simulated by the power system simulator according to the present embodiment. As shown in FIG. 1, in a power system 300, a power system A and a power system B are coupled via a distributed constant line 310 such as an electric wire.

  In this embodiment, the power system A is simulated by a digital simulator, and the power system B is simulated by an analog simulator. The electric power system B is a device connected to the electric power system 300, and is a device that operates at high speed, such as a power transmission line or a circuit breaker, a device that exhibits non-linear operation characteristics, such as a transformer, and Including equipment that is not fully understood. The power system A includes components other than the power system B in the power system 300. Further, the distributed constant line 310 is assumed to have characteristics of characteristic impedance Z and propagation time τ.

[Equivalent circuit of power system]
FIG. 2 shows an example of an equivalent circuit model of the power system 300 of FIG. The equivalent circuit model shown in FIG. 2 is the BERGERON coupling method. The BERGERON coupling method is an analysis method that divides the power system 300 into subsystems by using the propagation time τ of the distributed constant line 310.

  Specifically, in the equivalent circuit model based on the BERGERON coupling method, the transmission/reception end nodes are separated independently, and are represented by resistors R1 and R2 and equivalent current sources CS1 and CS2 at each end. The resistors R1 and R2 have values corresponding to the characteristic impedance (surge impedance) Z of the distributed constant line, and the values of the equivalent current sources CS1 and CS2 are determined by the voltage and current at each end at the past time. Therefore, one end (here, the power system A) of the distributed constant line 310 is simulated on the analog side and the other end (here, the power system B) is simulated on the digital side, and the voltage and current at each end are detected or calculated and calculated. Then, the analog simulator and the digital simulator can be connected by returning to the equivalent current source.

  Therefore, the equivalent circuit model shown in FIG. 2 is connected to the power system A, the current source CS1 connected to the power system A, the resistor R1 connected in parallel to the current source CS1, the power system B, and the power system B. It includes a current source CS2 and a resistor R2 connected in parallel with the current source CS2. A current from the power system A and a current from the current source CS1 flow through the resistor R1. In addition, a current from the power system B and a current from the current source CS2 flow in the resistor R2.

[Power system simulator configuration]
FIG. 3 shows the configuration of the power system simulator 1 that realizes the equivalent circuit model shown in FIG. The power system simulator 1 is a device that simulates the power system 300 illustrated in FIG. 1, and includes a digital simulator 110 that simulates the power system A (first power system) and a power system B (second power system). And an analog simulator 120 for performing the same. The power system simulator 1 also includes an interface 130 that connects the digital simulator 110 and the analog simulator 120 to each other. Hereinafter, they will be described in order.

(Digital simulator)
The digital simulator 110 is a digital computer and includes a first simulation unit 111 that simulates the power system A (first power system). As will be described later, the first simulation unit 111 executes numerical calculation based on a model in which the constituent elements of the power system A are simplified, and calculates the output current and the output voltage of the power system A.

  The digital simulator 110 is realized by a computer including a CPU, a RAM, and a ROM (not shown). The ROM stores programs for executing the respective functions of the first control unit 131 and the second control unit 132, which will be described later, for example, set values such as the characteristic impedance Z and the propagation time τ, calculation results, and the like. The CPU reads the program and various data stored in the ROM into the RAM, performs the calculation, outputs the calculation result which is a digital signal, and stores the result in the ROM.

(Analog simulator)
The analog simulator 120 includes a second simulation unit 121 in which components of the power system B (for example, a transmission line, a circuit breaker, a transformer, etc.) are miniaturized to simulate the power system B (second power system). The second simulation unit 121 outputs a simulation result that is an analog signal.

(Interface)
The interface 130 includes current sources 112 and 122, resistors 113 and 123, a voltage detector 124, a first controller 131, a second controller 132, an analog-digital converter 141, and a digital-analog converter 142. In the present embodiment, among the above-described components of the interface 130, the current source 112 (first current source), the resistor 113 (first resistor), the first control unit 131, and the second control unit 132 are included in the digital simulator 110. The current source 122 (second current source), the resistor 123 (second resistor), and the voltage detector 124 are included in the analog simulator 120. However, the above components of the interface 130 may be a device independent of the digital simulator 110 and the analog simulator 120. Hereinafter, the components of the interface 130 will be described in order.

  The current source 112 on the digital simulator 110 side is connected to the first simulation unit 111. The method of calculating the value of the current source 112 will be described later in relation to the first controller 131. The resistor 113 is connected in parallel with the current source 112 and exhibits a resistance value corresponding to the characteristic impedance Z of the distributed constant line 310.

  The current source 122 on the analog simulator 120 side is connected to the second simulation unit 121. The method of calculating the value of the current source 122 will be described later in relation to the second controller 132. Further, the resistor 123 is connected in parallel with the current source 122 and exhibits a resistance value corresponding to the characteristic impedance Z like the resistor 113.

The first controller 131 controls the current source 112 on the digital simulator 110 side. Specifically, the first control unit 131 outputs the output current i ₁ and the output voltage v _{1 of} the power system A calculated by the first simulation unit 111, and the output of the power system B output from the second simulation unit 121. The value of the current source 112 is calculated based on the voltage v ₂ and the control signal i ₁ ^* is output. At that time, the first control unit 131 may control the current source 112 based on the delay time generated in the output of the second simulation unit 121. Further, the first control unit 131 may control the current source 112 based on the propagation time τ in the distributed constant line 310. The procedure for determining the value of the current source 112 will be described later.

The second control unit 132 controls the current source 122 on the analog simulator 120 side. Specifically, the second control unit 132 calculates the value of the current source 122 based on the output current i ₁ and the output voltage v ₁ of the power system A calculated by the first simulation unit 111, and the control signal i ₂ ^* ' is output. The procedure for determining the value of the current source 122 will be described later.

The voltage detector 124 detects the output voltage of the second simulation section 121 and outputs an analog signal v ₂ indicating the detection result to the analog-digital converter 141. The analog-digital converter 141 converts the analog signal v ₂ into a digital signal v ₂ ′ and outputs it to the first controller 131. The voltage detector 124 may have a built-in analog-digital conversion function. In that case, the voltage detector 124 outputs the detection result to the first controller 131.

  Signal delay occurs during analog-to-digital conversion. In this embodiment, for convenience, the delay time of the signal is equal to the propagation time τ of the distributed constant line 310. When the delay generated in the analog-digital conversion is larger than the propagation time τ, the apparent conversion delay is made equal to the propagation time τ by the signal prediction process or the like. When the conversion delay is smaller than the propagation time τ, a delay element is added by signal processing to make the apparent conversion delay equal to the propagation time τ. Such signal delay processing may be performed by the first control unit 131, for example.

The control signal i ₂ ^* 'output from the second controller 132 is converted into an analog signal i ₂ ^* by the digital-analog converter 142 and output to the current source 122. Where a signal delay occurs even in such digital-analog conversion, the signal delay time is assumed to be equal to the propagation time τ of the distributed constant line 310 here as well. When the signal delay generated in the digital-analog conversion is not equal to the propagation time τ, the signal delay processing is performed in the first control unit 131 and the second control unit 132 as in the analog-digital conversion described above. Be seen.

  A current detector for detecting the output current of the second simulation section 121 is not provided on the analog simulator 120 side. Instead of the current detector, the first control unit 131 incorporates a function of estimating the output current of the analog second simulation unit 121 as described later.

[Procedure for determining current source value]
A procedure for determining the values of the current sources 112 and 122 in the first controller 131 and the second controller 132 will be described with reference to FIGS. 3 and 4. First, the procedure for determining the value of the current source 122 on the analog simulator 120 side will be described, and then the procedure for determining the value of the current source 112 on the digital simulator 110 side will be described.

(Procedure for determining the current source value on the analog simulator side)
The value of the current source 122 on the analog simulator 120 side is determined by the second controller 132. First, the output current i ₁ (t) and the output voltage v ₁ (t) of the power system A at a certain time t (first time) calculated by the first simulation unit 111 are input to the second control unit 132. It The second control unit 132 calculates the value i ₂ ^* '(t) of the current source 122 based on the following (Equation 1) as shown by the equation a in FIG. 3.

The value i ₂ ^* '(t) of the current source 122 is converted into an analog signal i ₂ ^* in the digital-analog converter 142. At that time, a conversion delay equal to the propagation time τ occurs as described above. Therefore, the control signal i ₂ ^* (t) input to the current source 122 at the time t is at the time (second time) before the time t by the propagation time τ, as shown in the following (Equation 2). It is defined by the output current i ₁ (t−τ) and the output voltage v ₁ (t−τ) of the power system A.

Therefore, the current source 122 can be controlled based on the current source J ₂ (t) defined by the following (Equation 3).

(Procedure for determining the current source value on the digital simulator side)
The value of the current source 112 on the digital simulator 110 side is determined by the first controller 131. Here, in the power system simulator 2 shown in FIG. 5, the value i _a ^* of the current source 212 on the digital simulator 210 side is generated based on the output voltage v _b and the output current i _b of the analog simulator 220 ( In the power system simulator 1 according to the present embodiment, the output current of the analog simulator 220 is not detected, so it is necessary to generate an estimated value of the output current on the digital simulator 110 side. Such a process is the block represented by the equation b in FIG. Then, the value i ₁ ^* of the current source 112 is calculated based on the estimated value i ₂ ′ of the output current of the analog simulator 220 and the detection result v ₂ of the output voltage of the analog simulator 220.

Therefore, first, the procedure for calculating the estimated value i ₂ ′ of the output current of the analog simulator 220 (the block represented by the equation b in FIG. 3) will be described. The output voltage v ₂ (t) of the second simulation section 121 at time t is converted into a digital signal v ₂ ′ by the analog-digital converter 141 and output to the first control section 131. Since the digital signal v ₂ ′ is delayed by the propagation time τ with respect to v ₂ , there is a relationship of v ₂ ′(t)=v ₂ (t−τ).

The digital signal v ₂ ′(t) is input to the first controller 131 together with the current signal i ₂ ^* ′(t) from the second controller 132. As described above, the voltage signal v ₂ ′ is delayed with respect to v ₂ by the propagation time τ, whereas the current signal i ₂ ^* ′ is not delayed. Accordingly, the first control unit 131 first adjusts the delay time between the 'signal _i ^{2 *'} signal _{v 2} and.

The adjustment of the delay time described above is realized, for example, by multiplying the signal I ₂ ^* 'by the ^dead time element e ^-2τs to generate I ₂ ^* 'e ^-2τs, as shown in block 151 of FIG. It In FIG. 4, the Laplace transforms of the signals v ₂ ′, i ₂ ^* ′, and i ₂ ′ are represented by V ₂ ′, I ₂ ^* ′, and I ₂ ′, respectively. Moreover, "s" represents a Laplace operator.

On the other hand, the signal V2′ from the analog-to-digital converter 141 is multiplied by 1/Z in the block 152 to generate the signal V2′/Z. Then, in the adder 153, the signal V2′/Z is added and the signal I ₂ ^* 'e ^−2τs is subtracted to generate the signal I2′. This process is shown in (Formula 4) below.

Inverse Laplace transform of this (formula 4) yields the following (formula 5).

Using the estimated value i ₂ ′ of the output current of the analog simulator 120 thus calculated and the detection result v ₂ of the output voltage of the analog simulator 220, the current source 112 is calculated based on the following (Equation 6). The value i ₁ ^{* of} is calculated.

Then, by substituting (Equation 1) and the relational expression v ₂ ′(t)=v ₂ (t−τ) into (Equation 6), the following (Equation 7) is obtained.

Therefore, the current source 112 can be controlled based on the current source J ₁ (t) defined by the following (Equation 8).

  As described above, in the present embodiment, by adding the process of estimating the output current of the second simulation unit 121, the current detector on the analog simulator 110 side becomes unnecessary. Further, when estimating the output current of the second simulation section 121, processing is performed in consideration of delay in signal exchange between digital and analog. As a result, the time between the output voltage of the second simulation unit 121 detected by the voltage detector 124 and the calculated estimated value of the output current of the second simulation unit 121 is made to coincide, and the second simulation unit 121 The accuracy of the estimated value of the output current is secured.

  According to this embodiment, no current detector is required on the analog simulator 120 side. Therefore, a simulation error due to the influence of the current detector on the analog simulator 120 can be eliminated, and highly accurate simulation can be performed. Also, the cost of the simulator equipment can be reduced.

[Summary]
As described above, the power system simulator 1 includes the first simulation unit 111 that simulates the power system A and the second simulation unit 121 that simulates the power system B connected to the power system A via the distributed constant line 310. , The current source 112 connected to the first simulation unit 111 and the current source 112 connected in parallel so that the current from the first simulation unit 111 and the current from the current source 112 flow, and the characteristic impedance of the distributed constant line 310. A resistor 113 indicating Z, a current source 122 connected to the second simulation unit 121, and a current source 122 connected in parallel so that the current from the second simulation unit 121 and the current from the current source 122 may flow, The resistance 123 indicating the impedance Z, the output current i1 and the output voltage v1 of the power system A at the second time before the first time calculated by the first simulation unit 111, and the second simulation unit 121 are output. Based on the output voltage v2 of the power system A at the second time, the first controller 131 that controls the current source 112, and the current source 122 based on the output current i1 and the output voltage v1 of the power system A at the second time. A second control unit 132 for controlling the. According to such an embodiment, a current detector that may affect the second simulation unit 121 of the analog simulator 120 can be omitted, so that a simulation error is suppressed and a power system that realizes a highly accurate simulation. A simulator can be provided.

  The first control unit 131 may further control the current source 112 based on the delay time τ that occurs in the output of the second simulation unit 121. According to this embodiment, the first control unit 131 can supply a highly accurate instruction signal in consideration of the delay time τ to the current source 112, which leads to improvement in simulation accuracy.

  The first control unit 131 may further control the current source 112 based on the propagation time τ in the distributed constant line 310. According to this embodiment, the first control unit 131 can supply a highly accurate instruction signal in consideration of the propagation time τ to the current source 112, which leads to improvement in simulation accuracy.

で定義される電流源Ｊ_１（ｔ）に基づいて、電流源１１２を制御し、第２制御部１３２は、電力系統Ａにおける過去の出力電圧ｖ_１（ｔ−τ）、電力系統Ａにおける過去の出力電流ｉ_１（ｔ−τ）を用いて、

で定義される電流源Ｊ_２（ｔ）に基づいて、電流源１２２を制御してもよい。かかる実施形態によれば、第２模擬部１２１の出力電流を推定する際には、ディジタル−アナログ間の信号交換における遅延を考慮した処理が行われる。これにより、電圧検出器１２４で検出された第２模擬部１２１の出力電圧と、算出された第２模擬部１２１の出力電流の推定値と、の間の時刻を一致させ、第２模擬部１２１の出力電流の推定値の精度を確保している。このことは、精度の高いシミュレーションを可能とする。 The first control unit 131 also controls the predetermined delay time τ, the characteristic impedance Z of the distributed constant line 310, the past output voltage v ₂ (t−τ) in the power system B, and the past output current i ₁ in the power system A. (T−2τ) and the past output voltage v ₁ (t−2τ) in the power system A,

The current source 112 is controlled based on the current source J ₁ (t) defined by, and the second controller 132 controls the past output voltage v ₁ (t−τ) in the power system A and the past in the power system A. Output current i ₁ (t−τ) of

The current source 122 may be controlled based on the current source J ₂ (t) defined by According to such an embodiment, when estimating the output current of the second simulation unit 121, processing is performed in consideration of delay in signal exchange between digital and analog. As a result, the time between the output voltage of the second simulation unit 121 detected by the voltage detector 124 and the calculated estimated value of the output current of the second simulation unit 121 is made to coincide, and the second simulation unit 121 The accuracy of the estimated value of the output current is secured. This enables highly accurate simulation.

  Alternatively, an interface for mutually connecting a digital simulator simulating the first power system and an analog simulator simulating the second power system connected to the first power system via an electric wire is connected to the digital simulator. The first current source is connected in parallel with the first current source so that the current from the digital simulator and the current from the first current source flow, and the first resistance indicating the characteristic impedance of the electric wire is connected to the analog simulator. A second current source, a second resistor connected in parallel with the second current source so that a current from the analog simulator and a current from the second current source flow, and showing a characteristic impedance; A first current source is controlled based on the output current and the output voltage of the first power system at the second time before the one time, and the output voltage of the second power system at the second time output from the analog simulator. One control device and a second control device that controls the second current source based on the output current and the output voltage of the first power system at the second time. According to such an embodiment, since the current detector that may affect the second simulation unit 121 of the analog simulator 120 can be omitted, the power system that suppresses the simulation error and realizes a highly accurate simulation. A simulator interface can be provided.

  Alternatively, the program mutually connects a digital simulator simulating the first power system and an analog simulator simulating the second power system connected to the first power system via an electric wire, and connects to the digital simulator. A first current source, a first resistance connected to the first current source in parallel so that a current from the digital simulator and a current from the first current source flow, and a characteristic impedance of an electric wire; and an analog simulator. An interface having a second current source connected to the second current source and a second resistor connected to the second current source in parallel so that the current from the analog simulator and the current from the second current source flow and showing a characteristic impedance. On the other hand, the output current and the output voltage of the first electric power system at the second time before the first time calculated by the digital simulator, and the output voltage of the second electric power system at the second time output from the analog simulator Based on the first function of controlling the first current source connected to the digital simulator, and the second current source connected to the analog simulator based on the output current and output voltage of the first power system at the second time. And a second function of controlling. According to such an embodiment, since the current detector that may affect the second simulation unit 121 of the analog simulator 120 can be omitted, the power system that suppresses the simulation error and realizes a highly accurate simulation. A simulator execution program can be provided.

  It should be noted that the above-described embodiments are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. The present invention can be modified and improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

1 Power System 110 Digital Simulator 111,121 Simulation Unit 112,122 Current Source 113,123 Resistor 124 Voltage Detector 120 Analog Simulator 130 Interface 131 First Control Unit 132 Second Control Unit

Claims (6)

A digital simulator simulating the first power system;
An analog simulator for simulating a second power system connected to the first power system via an electric wire;
A first current source connected to the digital simulator;
A first resistor connected in parallel with the first current source so that a current from the digital simulator and a current from the first current source flow, and showing a characteristic impedance of the electric wire;
A second current source connected to the analog simulator;
A second resistor connected in parallel with the second current source so that the current from the analog simulator and the current from the second current source flow, and showing the characteristic impedance;
Output current and output voltage of the first electric power system at a second time before the first time calculated by the digital simulator, and output of the second electric power system at the second time output from the analog simulator. A first controller that controls the first current source based on a voltage;
A second controller that controls the second current source based on the output current and the output voltage of the first power system at the second time;
An electric power system simulator comprising: The power system simulator according to claim 1, wherein the first control device further controls the first current source based on a delay time generated in the output of the analog simulator. The power system simulator according to claim 2, wherein the first control device further controls the first current source based on a propagation time in the electric wire. The first control device has a predetermined delay time τ, a characteristic impedance Z of the electric wire, a past output voltage v ₂ (t−τ) in the second power system, and a past output current i ₁ in the first power system. (T−2τ) and the past output voltage v ₁ (t−2τ) in the first power system,

Controlling the first current source based on the current source J ₁ (t) defined by
The second control device uses the past output voltage v ₁ (t−τ) in the first power system and the past output current i ₁ (t−τ) in the first power system,

The power system simulator according to claim 2 or 3, wherein the second current source is controlled based on the current source J ₂ (t) defined in (4) . An interface for mutually connecting a digital simulator simulating a first power system and an analog simulator simulating a second power system connected to the first power system via an electric wire,
A first current source connected to the digital simulator;
A first resistor connected in parallel with the first current source so that a current from the digital simulator and a current from the first current source flow, and showing a characteristic impedance of the electric wire;
A second current source connected to the analog simulator;
A second resistor that is connected in parallel with the second current source so that a current from the analog simulator and a current from the second current source flow and that exhibits the characteristic impedance;
Output current and output voltage of the first electric power system at the second time before the first time calculated by the digital simulator, and output of the second electric power system at the second time output from the analog simulator. A first controller that controls the first current source based on a voltage;
A second controller that controls the second current source based on the output current and the output voltage of the first power system at the second time;
An interface characterized by comprising. A digital simulator for simulating a first power system and an analog simulator for simulating a second power system connected to the first power system via an electric wire are mutually connected and connected to the digital simulator. A first current source, a first resistor connected in parallel with the first current source so that a current from the digital simulator and a current from the first current source flow, and showing a characteristic impedance of the electric wire; and the analog. A second current source connected to the simulator, and a second resistor connected in parallel with the second current source so that the current from the analog simulator and the current from the second current source flow and which exhibits the characteristic impedance. For interfaces with and,
Output current and output voltage of the first electric power system at the second time before the first time calculated by the digital simulator, and output of the second electric power system at the second time output from the analog simulator. A first function of controlling a first current source connected to the digital simulator based on a voltage;
A second function of controlling a second current source connected to the analog simulator based on an output current and an output voltage of the first power system at the second time point;
A program to execute.

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