KR20120071915A - Design apparatus and method for the distributed circuit analysis of high temperature superconductor cable - Google Patents

Abstract

PURPOSE: A distribution constant circuit analysis model designing apparatus of a superconductive cable and a method thereof are provided to previously evaluate effect on a real system before inserting a power device such as a superconductive cable into the real system. CONSTITUTION: A cable layer structure modeler(110) is equivalent to a layer structure of a superconductor cable. A three-phase pipe type cable modeler(120) models a three-phase pipe type of the superconductor cable. A superconductor quench effect modeler(140) models impedance change through a varister/reactor device.

Description

Design Apparatus and Method for the Distributed Circuit Analysis of High Temperature Superconductor Cable}

The present invention relates to a superconducting cable distribution constant circuit analysis model design device and design method, and more particularly, before the superconducting cable, especially power equipment such as 22.9kV / 50MVA superconducting cable under development in LS Cable, The present invention relates to an analysis model design device and a design method of superconducting cable distribution constant circuit for evaluating the effect on the real system in advance.

The superconductivity phenomenon refers to the characteristic that the electrical resistance flowing to the conductor in the cryogenic state is 0, and the superconducting cable is a power cable manufactured to realize such characteristics. In order to implement such a superconducting phenomenon, liquid nitrogen is used, and the conductor has superconductivity due to the cryogenic temperature of the liquid nitrogen.

The terminal of the superconducting cable is equipped with a terminal junction box, the terminal junction box is equipped with an externally extending terminal conductor, and the terminal conductor is connected to the core.

Looking at the structure of the superconducting cable, the inner metal tube is wrapped around the core, the inner metal tube is surrounded by the outer metal tube, the inner metal tube is filled with liquid nitrogen, and the vacuum between the inner metal tube and the outer metal tube to maximize the thermal insulation effect.

Currently, LS Cable is designing and manufacturing 22.9kV / 50MVA superconducting cable for Icheon Substation Seal System. In order to apply superconducting cables to real systems, detailed system analysis is essential for system impact assessment. In general, one of the system analysis programs widely used in the system application analysis of power distribution power equipment is PSCAD / EMTDC (Power System Computer-Aided Design / Electromagnetic Transients including DC). The basic library of PSCAD / EMTDC has a built-in analysis model of power equipment (line, transformer, breaker, etc.) widely used now, but there is no analysis model of newly developed (new) power equipment such as superconducting cable.

The present invention has been devised to solve the above-mentioned problems, and the effect of the superconducting cable, in particular, the power system, such as 22.9 kV / 50MVA superconducting cable, which is being developed by LS Cable, in advance on the real system beforehand. The purpose of the present invention is to provide an apparatus and method for designing an analytical model for superconducting cable distribution constant circuits.

Superconducting cable distribution constant circuit analysis model design apparatus according to an embodiment of the present invention for achieving the above object, is modeled by equalizing the layer structure of the superconducting cable into eight layers, the cryostat inside and outside Cable layer structure modeling unit for modeling the ground resistance; A three-phase batch pipe type cable modeling unit for modeling by replacing the three-phase batch pipe-type of the superconducting cable with earth equivalent; And a superconductor Quench phenomenon modeling unit for equivalently modeling the impedance change of the superconductor using a variable resistor / reactor element, and characterized in that each modeling result is simulated using a PSCAD / EMTDC program.

The above-described superconducting cable distribution constant circuit analysis model design apparatus may further include a concentric axial cable modeling unit for modeling the superconducting cable as a concentric axial cable. In this case, it is desirable to apply the set error in terms of voltage and current to the simulated results based on the modeling of the concentric axial cable.

The cable layer structure modeling unit includes a superconductor cable from the inner side to the outer side of the first conductor layer of the former, the first insulating layer, the second conductor layer of the high temperature superconductor (HTS), the second insulating layer, and the shield. The third conductor layer, the third insulation layer, the fourth conductor layer, and the fourth insulation layer of the high temperature superconductor may be modeled.

In addition, the cable layer structure modeling unit, the first conductor layer and the fourth conductor layer is copper, the second conductor layer and the third conductor layer are superconductors, the first insulating layer and the third insulating layer are carbon paper. The second insulating layer may be made of polypropylene laminated paper (PPLP), and the fourth insulating layer may be made of nylon tape.

In addition, the cable layer structure modeling unit, the first conductor layer and the second conductor layer are interconnected in the terminal box, the three phases from the connection point interconnected between the third conductor layer and the fourth conductor layer are pulled together and collectively It can be modeled by connecting to an enclosure by connecting to a cryostat.

Superconductor Quench phenomenon modeling unit, Z _{HTS as} a nonlinear function of the current (I) and temperature (T) of the impedance change of the superconductor = f (I, T) can be modeled.

Superconducting cable distribution constant circuit analysis model design method according to an embodiment of the present invention for achieving the above object, equalizing the layer structure of the superconducting cable into eight layers, and the inner and outer cryostat is ground resistance Cable layer structure modeling for equivalent modeling, 3-phase batch pipe-type cable modeling for modeling by replacing earth-equivalent three-phase pipe-type of superconducting cable, and variable resistance / reactor element to change impedance of superconductor A modeling step including modeling a superconductor Quench phenomenon equivalently modeling using; And a simulation step for simulating each modeling result using a PSCAD / EMTDC program.

The modeling step may further include concentric coaxial cable modeling for modeling the superconducting cable as a concentric coaxial cable. In this case, the set error in terms of voltage and current may be applied to the simulated result based on the modeling of the concentric axial cable.

In the cable layer structure modeling, the superconducting cable is formed from the inner side to the outer side of the first conductor layer of the former, the first insulating layer, the second conductor layer of the high temperature superconductor (HTS), the second insulating layer, and the shield. The third conductor layer, the third insulation layer, the fourth conductor layer, and the fourth insulation layer of the high temperature superconductor may be modeled.

In addition, the cable layer structure modeling, the first conductor layer and the fourth conductor layer is copper (copper), the second conductor layer and the third conductor layer is a superconductor, the first insulating layer and the third insulating layer is carbon paper The second insulating layer may be made of polypropylene laminated paper (PPLP), and the fourth insulating layer may be made of nylon tape.

In addition, in the cable layer structure modeling, the first conductor layer and the second conductor layer are interconnected in a terminal junction box, and the three phases are drawn together at a connection point where the third conductor layer and the fourth conductor layer are interconnected, It can be modeled by connecting to an enclosure by connecting to a cryostat.

Superconductor Quench phenomenon modeling is based on Z _HTS , which is a nonlinear function of current (I) and temperature (T) = f (I, T) can be modeled.

According to an embodiment of the present invention, it is possible to evaluate the effect on the real system in advance before inputting a power device, such as a 22.9 kV / 50 MVA superconducting cable, which is being developed in particular by LS Cable, to the real system. do.

1 is a view schematically showing a superconducting cable distribution constant circuit analysis model design apparatus according to an embodiment of the present invention.
2 is a diagram illustrating an example of a cable distribution constant circuit model provided in a PSCAD / EMTDC basic library.
3 is a diagram illustrating an example of a structure of a 22.9 kV / 50 MVA superconducting cable.
4 is a diagram illustrating an example of a structure modeled by modeling the superconducting cable of FIG. 2 into eight layers.
5 is a diagram illustrating an example of modeling a connection structure between superconducting cable conductors.
FIG. 6 illustrates an example in which a cryostat is modeled as a ground resistor and an impedance change of a superconductor is equivalently modeled using a variable resistor / reactor device.
7 is a flowchart illustrating a method for designing an analysis model of a superconducting cable distribution constant circuit according to an embodiment of the present invention.
8 is a PSCAD / EMTDC test system diagram applying a superconducting cable model to real system data of Icheon substation.
9 is a diagram showing the current distribution of the superconducting cable when energizing the load current as a simulation result.
FIG. 10 is a diagram illustrating a case where a system failure occurs in 0.4 seconds in a 22.9 kV bus bar at a rear end of a superconducting cable as a simulation result.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, a detailed description of known techniques well known to those skilled in the art may be omitted.

Modeling methods of transmission and distribution lines can be classified into PI circuit and distribution constant circuit method according to the system review purpose. The basic contents of each simulation method are as follows.

The PI circuit simulation method is a standard for steady-state analysis and effective value analysis, and models the transmission network as an algebraic equation. However, the PI circuit simulation method cannot examine the high frequency transient characteristics over kHz such as electromagnetic phenomena and surge analysis of the transmission network itself. In the instantaneous PSCAD / EMTDC analysis, the simulation of the PI circuit, that is, the phase voltage fluctuations in steady state and failure can be considered. But the surge phenomenon cannot be interpreted.

The distribution constant simulation method can simulate the instantaneous value of EMTDC, and it is the concept that the transmission line is divided into very short short distance lines, and the surge analysis and the voltage / current analysis of the sheath / shield / corrosion layer are possible. However, the distribution constant simulation method has a disadvantage that the analysis time is too long because the time step (Δt) must be very short in PSCAD / EMTDC analysis.

The present invention proposes an apparatus and method for designing an analytical model of a distribution constant circuit method for examining the surge analysis and floor current distribution of a superconducting cable.

1 is a view schematically showing a superconducting cable distribution constant circuit analysis model design apparatus according to an embodiment of the present invention. Referring to the drawings, the superconducting cable distribution constant circuit analysis model design apparatus 100 according to an embodiment of the present invention is the cable layer structure modeling unit 110, three-phase batch pipe type cable modeling unit 120, concentric coaxial cable modeling The unit 130 and the superconductor quench phenomenon modeling unit 140 are included.

The cable layer structure modeling unit 110 models the layer structure of the superconducting cable by eight layers, and models the inner and outer low-temperature holding layers (cryostat) by equalizing the ground resistance.

As shown in FIG. 2, the cable distribution constant circuit model provided in the PSCAD / EMTDC basic library may input up to eight layer structures. Divided into layers, it is the same as [Conductor 1 ↔ Insulator 1 ↔ Conductor 2 ↔ Insulator 2 ↔ Conductor 3 ↔ Insulator 3 ↔ Conductor 4 ↔ Insulator 4]. For each conductor layer, the outer (radius), resistivity (Ω-m) and specific permeability can be entered, and for the insulator layer, the outer (radius), relative dielectric constant and relative permeability can be entered. On the other hand, the structure of the 22.9kV / 50MVA superconducting cable, which is currently developed in Korea, is shown in FIG. However, the cable layer structure modeling unit 110 is modeled by equalizing the eight layers as shown in Table 1 and FIG. 4 in consideration of the characteristics of each layer of the superconducting cable, and simulates the internal and external low-temperature holding layer by the ground resistance.

[Table 1]

That is, the cable layer structure modeling unit 110 may form the superconducting cable from the inner side to the outer side of the first conductor layer, the first insulation layer of the former, the second conductor layer of the high temperature superconductor (HTS), and the second insulation. The layer may be modeled as a third conductor layer, a third insulation layer, a fourth conductor layer, and a fourth insulation layer of a shield high temperature superconductor. In this case, the cable layer structure modeling unit 110, the material of the first conductor layer and the fourth conductor layer is copper (copper), the material of the second conductor layer and the third conductor layer is a superconductor, the first insulating layer and the third insulation The material of the layer may be modeled as carbon paper, the material of the second insulating layer is polypropylene laminated paper (PPLP), and the material of the fourth insulating layer is nylon tape.

In addition, the connection structure between the superconducting cable conductor can be modeled as shown in FIG. In other words, [Conductor 1 Former] and [Conductor 2 HTS Layer] are interconnected in the terminal junction box, and [Conductor 3 Shield HTS Layer] and [Conductor 4 Shield Stabilizer] are interconnected and modeled. In the embodiment of the present invention, three phases are drawn from the connection points of [Conductor 3 Shield HTS Layer] and [Conductor 4 Shield Stabilizer] and collectively connected to internal and external Cryostat to be connected to the enclosure. In addition, Cryostat can be equivalently simulated as a resistance element as shown in FIG.

Pipe type cable simulation is not possible in PSCAD / EMTDC. However, since the superconducting cable is laid on the ground, the three-phase collective pipe type cable modeling unit 120 of the superconducting cable distribution constant circuit analysis model designing apparatus 100 according to the embodiment of the present invention, as shown in FIG. Model the three-phase batch pipe type of cable by replacing it with earth equivalent.

Since the superconducting cable is not a complete concentric cable, it may not be 100% accurate. However, since the error of the superconducting cable is not very large in terms of voltage and current in the analysis of the system, the concentric cable modeling unit 130 uses a superconducting cable. It can be modeled assuming concentric cable. In this case, the simulation result based on the modeling of the concentric axial cable may be corrected by applying a set error in terms of voltage and current.

The superconductor quench phenomenon modeling unit 140 may equivalently model the impedance change of the superconductor using a variable resistor / reactor device.

In practice, the superconductor has a value close to zero when the normal current is energized. When the superconductor is energized above the critical current, the superconductor becomes a quench and changes to an insulator-like state. Since the cable element of the PSCAD / EMTDC cannot directly simulate the resistivity / permeability change due to the Quench of the HTS (High Temperature Superconductor) layer, the superconductor Quench phenomenon modeling unit 140 separates the impedance change of the superconductor as shown in FIG. 6. Equivalently simulate using a variable resistor / reactor element.

At this time, the change of the impedance (Z _HTS ) of the superconductor is modeled as a nonlinear function of the current (I) and the temperature (T) as shown in Equation 1.

[Equation 1]

Z _HTS = f (I, T)

Each modeled result is simulated using the PSCAD / EMTDC program to analyze the distribution constant circuit of the superconducting cable.

7 is a flowchart illustrating a method for designing an analysis model of a superconducting cable distribution constant circuit according to an embodiment of the present invention.

Referring to FIGS. 1 and 7, the cable layer structure modeling unit 110 equalizes the layer structure of the superconducting cable into eight layers, and models the inner and outer cryostats by equalizing the ground resistance. Phase batch pipe type cable modeling unit 120 is modeled by replacing the three-phase batch pipe type of the superconducting cable to earth equivalent, as shown in Figure 4, the concentric coaxial cable modeling unit 130 is a superconducting cable It is modeled on the assumption that the superconductor Quench phenomenon modeling unit 140 may model the impedance change of the superconductor equivalently using a variable resistor / reactor device (S710).

At this time, the cable layer structure modeling unit 110, the superconducting cable from the inner side to the outer direction, the first conductor layer of the former (former), the first insulating layer, the second conductor layer of the high temperature superconductor (HTS), the second insulation The layer may be modeled as a third conductor layer, a third insulation layer, a fourth conductor layer, and a fourth insulation layer of a shield high temperature superconductor. In addition, the cable layer structure modeling unit 110 may be made of copper (copper), material of the second conductor layer and the third conductor layer of the first conductor layer and the fourth conductor layer. The material of the layer may be modeled as carbon paper, the material of the second insulating layer is polypropylene laminated paper (PPLP), and the material of the fourth insulating layer is nylon tape. In addition, the cable layer structure modeling unit 110 interconnects the [Conductor 1 Former] and the [Conductor 2 HTS Layer] in the termination box, and the [Conductor 3 Shield HTS Layer] and the [Conductor 4 Shield Stabilizer] are also interconnected. Model it. In the embodiment of the present invention, three phases are drawn from the connection points of [Conductor 3 Shield HTS Layer] and [Conductor 4 Shield Stabilizer] and collectively connected to internal and external Cryostat to be connected to the enclosure. In addition, Cryostat can be equivalently simulated as a resistance element as shown in FIG. In addition, the superconductor Quench phenomenon modeling unit 140 may model the change of the impedance (Z _HTS ) of the superconductor as a nonlinear function of the current (I) and the temperature (T) as shown in Equation (1).

The simulation is performed on each modeling result using the PSCAD / EMTDC program (S720). Simulation method is the same as the simulation method in the general cable distribution constant circuit model, the detailed description thereof will be omitted.

If an analysis model for distributed constant circuits of PSCAD / EMTDC superconducting cables is developed using the proposed design method in the present invention, there is a slight error because it is equivalently simulated from an engineering point of view, but it is sufficient to be used for the overall system impact evaluation.

Using the analysis model design device and design method of the superconducting cable distribution constant circuit according to an embodiment of the present invention, the simulation for the system impact evaluation of 22.9kV / 50MVA superconducting cable for Icheon substation. 8 is a PSCAD / EMTDC test system diagram applying a superconducting cable model to real system data of Icheon substation. It is assumed that 500m of 22.9kV / 50MVA superconducting cable is installed between the secondary side of # 5 peripheral transformer (M.Tr) and 22.9kV busbar of Icheon substation. The total load was 45 MW and the power factor was 092. The primary side of the # 5 periphery was simulated as LA ground, and the secondary side as it was currently installed. An ancestor system of 5MVA × 4 was applied to the 22.9kV bus bar.

As a result of the simulation, the current flowing for each part of the superconducting cable was confirmed. 9 and 10 show current distributions in phase A. FIG. 9 is a diagram showing the current distribution of the superconducting cable when energizing the load current. In the results of FIG. 9, it can be seen that almost 100% of current flows through the superconductors (Conductor 2 HTS Layer and Conductor 3 Shield HTS Layer) when the load current is energized. 10 is a case where the system failure occurs in 0.4 seconds in the 22.9kV bus bar at the rear end of the superconducting cable. In this case, the superconductor is quenched due to the fault current flowing in the superconducting cable, and resistance is generated. As a result, about 99% of the fault current flows to the stabilization layer (Conductor 1 Former and Conductor 4 Shield Stabilizer).

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. In addition, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, the protection scope of the present invention should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: Superconducting cable distribution constant circuit analysis model design device
110: cable layer structure modeling unit
120: 3-phase batch pipe type cable modeling unit
130: concentric shaft cable modeling unit
140: superconductor quench phenomenon modeling unit

Claims (12)

A cable layer structure modeling unit for modeling the layer structure of the superconducting cable by eight layers and modeling the inner and outer cryostats by ground resistance;
A three-phase batch pipe type cable modeling unit for modeling the three-phase batch pipe-type of the superconducting cable by earth equivalent; And
Superconductor Quench phenomenon modeling unit for equivalently modeling impedance change of superconductor using variable resistor / reactor device
Including;
A superconducting cable distribution constant circuit analysis model design device, characterized in that each modeling result is simulated using a PSCAD / EMTDC program.
The method of claim 1,
Concentric axial cable modeling unit for modeling the superconducting cable as a concentric axial cable
More,
Superconducting cable distribution constant circuit analysis model design device, characterized in that for applying the set error in terms of voltage, current in the simulation results based on the modeling of the concentric axial cable.
The method of claim 1,
The cable layer structure modeling unit,
The superconducting cable is formed from a first conductor layer, a first insulating layer, a second conductor layer of a high temperature superconductor (HTS), a second insulating layer, and a shield (high temperature) superconductor from the inner side to the outer side of the former. A superconducting cable distribution constant circuit analysis model designing apparatus, characterized by modeling the conductor layer, the third insulation layer, the fourth conductor layer, and the fourth insulation layer.
The method of claim 3, wherein
The cable layer structure modeling unit,
The first conductor layer and the fourth conductor layer are copper, the second conductor layer and the third conductor layer are superconductors, the first insulating layer and the third insulating layer are carbon paper, The second insulating layer is PPLP (Polypropylene Laminated Paper), and the fourth insulating layer is a superconducting cable distribution constant circuit analysis model design device, characterized in that the model of nylon tape (Nylon Tape) material.
The method of claim 3, wherein
The cable layer structure modeling unit,
The first conductor layer and the second conductor layer are interconnected in a termination box, and pulled three phases at a connection point where the third conductor layer and the fourth conductor layer are interconnected to collectively bundle the inside and the outside of the low temperature holding layer. Superconducting cable distribution constant circuit analysis model design device, characterized in that connected to the model by connecting to the enclosure.
The method of claim 1,
The superconductor quench phenomenon modeling unit,
The impedance change of the superconductor is Z _HTS which is a nonlinear function of current (I) and temperature (T). Superconducting cable distribution constant circuit analysis model design device, characterized in that modeling by f (I, T).
The layer structure of the superconducting cable is equalized to eight layers, and the inner and outer cryostats are modeled by equalizing the ground resistance to the cable layer structure modeling, and the three-phase collective pipe-type of the superconducting cable. A modeling step including three-phase batch pipe type cable modeling to replace the earth equivalent model, and superconductor Quench phenomenon modeling to equivalently model the impedance change of the superconductor using a variable resistor / reactor element; And
Simulation step to simulate each modeling result using PSCAD / EMTDC program
Superconducting cable distribution constant circuit analysis model design method comprising a.
The method of claim 7, wherein the modeling step,
Further comprising a concentric axial cable modeling for modeling the superconducting cable as a concentric axial cable,
A method for designing an analysis model for superconducting cable distribution constant circuits, comprising applying a set error in terms of voltage and current to a simulated result based on the modeling of the concentric axial cable.
8. The method of claim 7,
The cable layer structure modeling,
The superconducting cable is formed from a first conductor layer, a first insulating layer, a second conductor layer of a high temperature superconductor (HTS), a second insulating layer, and a shield (high temperature) superconductor from the inner side to the outer side of the former. A superconducting cable distribution constant circuit analysis model design method characterized by modeling the conductor layer, the third insulation layer, the fourth conductor layer and the fourth insulation layer.
The method of claim 9,
The cable layer structure modeling,
The first conductor layer and the fourth conductor layer are copper, the second conductor layer and the third conductor layer are superconductors, the first insulating layer and the third insulating layer are carbon paper, The second insulation layer is PPLP (Polypropylene Laminated Paper), and the fourth insulation layer is a model of nylon tape (Nylon Tape), characterized in that the superconducting cable distribution constant circuit analysis model design method.
The method of claim 9,
The cable layer structure modeling,
The first conductor layer and the second conductor layer are interconnected in a termination box, and pulled three phases at a connection point where the third conductor layer and the fourth conductor layer are interconnected to collectively bundle the inside and the outside of the low temperature holding layer. Superconducting cable distribution constant circuit analysis model design method characterized in that connected to the model by connecting to the enclosure.
8. The method of claim 7,
The superconductor quench phenomenon modeling,
The impedance change of the superconductor is Z _HTS which is a nonlinear function of current (I) and temperature (T). A method for designing an analytical model for superconducting cable distribution constant circuits, characterized by modeling as f (I, T).

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