CN103825267A - Calculating method for short-circuit current on direct current side of MMC-MTDC (modular multi-level converter-based multi-terminal direct-current transmission system) - Google Patents

Calculating method for short-circuit current on direct current side of MMC-MTDC (modular multi-level converter-based multi-terminal direct-current transmission system) Download PDF

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CN103825267A
CN103825267A CN201410081588.8A CN201410081588A CN103825267A CN 103825267 A CN103825267 A CN 103825267A CN 201410081588 A CN201410081588 A CN 201410081588A CN 103825267 A CN103825267 A CN 103825267A
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mtdc
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conversion station
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徐政
张哲任
唐庚
刘昇
薛英林
李文云
吴琛
李玲芳
张丹
张�杰
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Zhejiang University ZJU
Yunnan Power Grid Co Ltd
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Yunnan Power Grid Co Ltd
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Abstract

The invention provides a calculating method for short-circuit current on the direct current side of an MMC-MTDC (modular multi-level converter-based multi-terminal direct-current transmission system). The calculating method comprises the steps of (1) calculating an MMC-MTDC direct-current network, and taking calculated steady-state operation current as a steady-state component of the short-circuit current; (2) performing equivalent conversion to obtain an equivalent passive circuit corresponding to an MMC; (3) calculating a fault component of the short-circuit current according to the MMC equivalent passive circuit, a direct-current power transmission line and a fault point direct-current voltage source equivalent calculating network; (4) adding the steady-state component and the fault component to obtain a final short-circuit current calculated result. Therefore, on the premise of guaranteeing the effectiveness, the efficiency for calculating the short-circuit current on the direct current side of the MMC-MTDC is obviously improved; due to the use of the method disclosed by the invention, the time for checking the requirement on the performance of a direct-current circuit breaker can be obviously shortened, so that the period for planning and designing the whole MMC-MTDC engineering is shortened; the calculating method has an important engineering practical value.

Description

A kind of computational methods of MMC-MTDC dc-side short-circuit electric current
Technical field
The invention belongs to electric power system technology of transmission of electricity field, be specifically related to a kind of computational methods of MMC-MTDC dc-side short-circuit electric current.
Background technology
Day by day exhausted along with the continuous aggravation of day by day serious, the environmental problem of energy shortage problem and petrochemical industry resource, China increases day by day to the demand of renewable resource in recent years.Due to the particularity of regenerative resource, must consider to adopt new technology, equipment and electric network composition to solve its grid-connected problem.The multiterminal flexible DC power transmission system of VSC-MTDC(based on voltage-source type converter) be considered to one of the most effective solution.
Along with the development of power electronic technology, the MMC(modularization multi-level converter based on full-control type device) greatly promote the development of high voltage dc transmission technology.As VSC(voltage-source type converter) one, MMC is in having VSC and having superiority, also have that device unanimously triggers that dynamic voltage balancing requirement is low concurrently, the many advantages such as the low and running wastage of favorable expandability, switching frequency is low, become the mainstream development trend of flexible DC power transmission.In order to improve the multiterminal flexible DC power transmission system of MMC-MTDC(based on modularization multi-level converter) electric pressure and transmission line capability, must adopt the dipolar configuration of similar traditional DC transmission system, also the positive pole (negative pole) that is current conversion station must at least be made up of a complete converter, as shown in Figure 1.
From the traditional DC transmission system of LCC-HVDC(based on electrical network commutation converter) different, in the time there is DC line fault, flexible direct current system cannot adopt the method for locking converter to carry out limiting short-circuit current.In order to ensure the safety of key equipment in the stable operation of multiterminal flexible DC power transmission system before and after fault and electrical network, faulty line must be excised within very short time come the size of limiting short-circuit current.Generally believe that at present high voltage DC breaker is to address this problem the most effective scheme.
Aspect high voltage DC breaker research, the research work of offshore company and research institution is carried out early, and has completed the development of corresponding model machine.ABB AB will announce to have succeeded in developing the hybrid circuit breaker based on conventional mechanical switch and power electronic device the end of the year 2012, declare in 5ms, to excise the fault current that is 8.5kA to the maximum.The development that Alstom company has also announced model machine in 2013.But be limited to the development of current semiconductor technology, possess the DC circuit breaker of major break down current breaking capacity more still in development.
Under DC Line Fault, the DC side equivalent capacity that MMC is larger can produce larger DC Line Fault electric current.For reasonable and effectively configuring direct current circuit breaker, conventionally need calculate fault current maximum under all possible DC Line Fault according to the actual characteristic of engineering, in order to check the performance requirement that whether meets DC circuit breaker.Therefore, the accuracy of dc-side short-circuit Current calculation is directly connected to the reliability of DC circuit breaker design, and dc-side short-circuit Current calculation also just correspondingly becomes the basis of verification DC circuit breaker performance requirement.In view of MMC-MTDC system exists multiple operating condition, and dc-side short-circuit fault may occur in any position in DC line, therefore must find not only accurately but also efficient dc-side short-circuit Current calculation method of one.
Can calculate dc-side short-circuit electric current by build detailed MMC-MTDC model in time-domain-simulation software at present.But, in time-domain-simulation software, build detailed simulation model not a duck soup, and need to consume a large amount of time and computing hardware for follow-up simulation calculation.Consider and in Practical Project, exist multiple operating condition, and dc-side short-circuit fault may occur in any position in DC line, the detailed model of building based on time-domain-simulation software is not very suitable for the calculating of dc-side short-circuit electric current.
Summary of the invention
For the existing above-mentioned technical problem of prior art, the invention provides a kind of computational methods of MMC-MTDC dc-side short-circuit electric current, can guarantee, under the prerequisite of computational accuracy, to significantly improve the computational efficiency of dc-side short-circuit electric current.
Computational methods for MMC-MTDC dc-side short-circuit electric current, comprise the steps:
(1) control strategy adopting according to current conversion station, carries out sequencing numbers to the each current conversion station in MMC-MTDC, and then according to the operating condition of system and major loop parameter, calculates the steady-state current of every DC power transmission line in MMC-MTDC;
(2), according to the operating condition of system and major loop parameter, each current conversion station in MMC-MTDC is carried out to equivalent transformation to set up the passive equivalence network of MMC-MTDC;
(3) if there is DC power transmission line short trouble in MMC-MTDC, in described passive equivalence network, on the direct current transmission line fault point of correspondence, add a voltage source is set, and then this equivalence passive network is carried out to time-domain-simulation, in the hope of every DC power transmission line two ends failure of the current component in MMC-MTDC;
(4), according to the steady-state current of DC power transmission line and circuit two ends failure of the current component, calculate the short circuit current at every DC power transmission line two ends in MMC-MTDC.
The standard of in described step (1), the each current conversion station in MMC-MTDC being carried out to sequencing numbers is: make to adopt the current conversion station of constant DC voltage control strategy to be numbered 1 in system, make to adopt the current conversion station of constant DC current control strategy to be numbered 2～m in system, make to adopt the current conversion station of determining power control strategy to be numbered m+1～M in system, m-1 is the total number that adopts the current conversion station of constant DC current control strategy in MMC-MTDC, and M is total number of current conversion station in MMC-MTDC.
The method of calculating every DC power transmission line steady-state current in MMC-MTDC in described step (1) is as follows:
A1. the direct current voltage equation of setting up MMC-MTDC is as follows:
Figure BDA0000474001860000031
Wherein: the node admittance matrix that Y is MMC-MTDC, I 1～I mthe direct current of exporting for being numbered the current conversion station of 1～M in MMC-MTDC, U 1～U mfor being numbered the direct voltage of current conversion station of 1～M, Y in MMC-MTDC 11, Y 12, Y 21and Y 22be submatrix and Y in node admittance matrix Y 11be 1 × 1 dimension, Y 12be 1 × (M-1) dimension, Y 21for (M-1) × 1 dimension, Y 22for (M-1) × (M-1) dimension, M is total number of current conversion station in MMC-MTDC;
A2. above formula is changed, obtained about direct voltage U 2～U mnonlinear equation F (U) as follows:
F ( U ) = F ( U 2 · · · U M ) = Y 21 U 1 + Y 22 U 2 · · · U M - I 2 · · · I m P m + 1 / 2 U m + 1 · · · P M / 2 U M = 0
Wherein: I 2～I mthe direct current of exporting for being numbered the current conversion station of 2～m in MMC-MTDC, U m+1～U mfor being numbered the direct voltage of current conversion station of m+1～M, P in MMC-MTDC m+1～P mfor being numbered the power output of current conversion station DC side of m+1～M in MMC-MTDC, m-1 is the total number that adopts the current conversion station of constant DC current control strategy in MMC-MTDC;
A3. adopt Newton-Raphson iterative method to solve above-mentioned nonlinear equation F (U), to obtain direct voltage U 2～U m;
A4. for arbitrary DC power transmission line in MMC-MTDC, make the direct voltage of its two ends current conversion station make the poor voltage in the hope of circuit two ends, thereby and then make this voltage obtain the steady-state current of this circuit divided by the resistance of circuit; Travel through according to this every DC power transmission line.
In described step (2), current conversion station is carried out to the specific implementation process of equivalent transformation as follows: make two MMC in current conversion station all equivalence become RLC(RLC resistance-inductance-capacitance) link, described RLC link is composed in series by capacitor C, inductance L and resistance R successively from input to output, the input common ground of two RLC links; Wherein, C=6C 0/ N, L=2L 0/ 3+L s, R=NR 0/ 3, C 0for the electric capacity in MMC change of current submodule, L 0for the brachium pontis reactance of MMC, R 0for the on state resistance of MMC change of current submodule, L sfor the flat ripple reactance of current conversion station DC side, N is the cascade number of the each brachium pontis change of current of MMC submodule.
In described step (3), definite method of voltage source voltage is as follows: for faulty line, determine the voltage of fault point on this circuit by linear interpolation method according to the direct voltage of its two ends current conversion station, to this voltage negate as the voltage of described voltage source.
In described step (4) for arbitrary DC power transmission line in MMC-MTDC, it is cumulative mutually with the steady-state component of this circuit two ends electric current respectively that the short circuit current at these circuit two ends equals this circuit two ends failure of the current component, and the steady-state component of described circuit two ends electric current is respectively I dcwith-I dc, I dcfor the steady-state current of this circuit; Travel through according to this every DC power transmission line.
The present invention is directed to and adopt the MMC-MTDC of dipolar configuration to propose a kind of method of calculating its dc-side short-circuit electric current, the method is based on simplified model, can significantly improve computational efficiency, thereby overcome the latent defect (expend time in and expend computational resource) of the time-domain-simulation based on detailed model.In view of the operating mode that may occur in actual MMC-MTDC engineering more, dc-side short-circuit fault may occur in any position in DC line, the method that the application of the invention proposes, and then can significantly reduce and check the time that DC circuit breaker performance requirement spends, and then shortened the cycle that whole MMC-MTDC project planning designs, there is important engineering practical value.
The present invention, according to the physics evolution of MMC-MTDC dc-side short-circuit electric current, is creatively decomposed into steady-state component and fault component, and therefore the physical significance of method proposed by the invention is comparatively clear and definite.For steady-state component, can determine by the direct current that calculates MMC-MTDC under corresponding operating condition; For fault component, can add a direct voltage source by the fault point place at MMC-MTDC DC side passive network (being formed by MMC passive equivalence circuit, flat ripple reactance and DC line) and calculate.By the decomposition of MMC-MTDC dc-side short-circuit electric current, can analyze very intuitively the impact on short circuit current of different operating conditions and different faults position: first, operating mode almost only affects the steady-state component to short circuit current, therefore can select the operating mode of steady-state component maximum to check operating mode as DC circuit breaker; Secondly, according to the computation model of short circuit current fault component, can know, maximum fault component appears under the short trouble at current conversion station direct current outlet bus place (smoothing reactor and DC line tie point place).Therefore, if desired check the performance requirement of DC circuit breaker, only consider under steady-state current maximum duty, occur in the short trouble of current conversion station DC line outlet.This can reduce the unnecessary simulation calculation causing because operating condition and fault occurrence positions are uncertain greatly.
Accompanying drawing explanation
Fig. 1 is the structural representation of current conversion station in MMC-MTDC.
Fig. 2 is the structural representation of certain three end MMC-MTDC.
Fig. 3 is the schematic flow sheet of MMC-MTDC dc-side short-circuit Current calculation method of the present invention.
Fig. 4 is the structural representation of MMC.
Fig. 5 is the passive equivalence circuit diagram of MMC.
Fig. 6 is the equivalent network schematic diagram for calculating dc-side short-circuit current failure component.
Fig. 7 be adopt the inventive method and calculate gained based on detailed model flow through 1. direct-current short circuit results of weak current contrast of node.
Fig. 8 be adopt the inventive method and calculate gained based on detailed model flow through the 2. contrast schematic diagram of direct-current short circuit results of weak current of node.
Fig. 9 be adopt the inventive method and calculate gained based on detailed model flow through the 3. contrast schematic diagram of direct-current short circuit results of weak current of node.
Figure 10 be adopt the inventive method and calculate gained based on detailed model flow through the 4. contrast schematic diagram of direct-current short circuit results of weak current of node.
Figure 11 be adopt the inventive method and calculate gained based on detailed model flow through the 5. contrast schematic diagram of direct-current short circuit results of weak current of node.
Figure 12 be adopt the inventive method and calculate gained based on detailed model flow through the 6. contrast schematic diagram of direct-current short circuit results of weak current of node.
Embodiment
In order more specifically to describe the present invention, below in conjunction with the drawings and the specific embodiments, technical scheme of the present invention is elaborated.
In present embodiment, as shown in Figure 2, its system parameters is as shown in table 1 for the structure of three end MMC-MTDC:
Table 1
Figure BDA0000474001860000074
As shown in Figure 3, calculate MMC-MTDC dc-side short-circuit electric current according to following methods step:
(1) control strategy adopting according to current conversion station, according to adopting the current conversion station of constant DC voltage control strategy, the current conversion station that adopts constant DC current control strategy and employing to determine this order of current conversion station of power, numbers all current conversion stations from 1 to M.According to the operating condition of system and major loop parameter, calculate the steady-state current of every DC power transmission line in MMC-MTDC, as the steady-state component of short circuit current;
A1. the direct current voltage equation of setting up MMC-MTDC is as follows:
Figure BDA0000474001860000075
Wherein: the node admittance matrix that Y is MMC-MTDC, I 1～I mthe direct current of exporting for being numbered the current conversion station of 1～M in MMC-MTDC, U 1～U mfor being numbered the direct voltage of current conversion station of 1～M, Y in MMC-MTDC 11, Y 12, Y 21and Y 22be submatrix and Y in node admittance matrix Y 11be 1 × 1 dimension, Y 12be 1 × (M-1) dimension, Y 21for (M-1) × 1 dimension, Y 22for (M-1) × (M-1) dimension, M is total number of current conversion station in MMC-MTDC;
A2. above formula is changed, obtained about direct voltage U 2～U mnonlinear equation F (U) as follows:
F ( U ) = F ( U 2 · · · U M ) = Y 21 U 1 + Y 22 U 2 · · · U M - I 2 · · · I m P m + 1 / 2 U m + 1 · · · P M / 2 U M = 0
Wherein: I 2～I mthe direct current of exporting for being numbered the current conversion station of 2～m in MMC-MTDC, U m+1～U mfor being numbered the direct voltage of current conversion station of m+1～M, P in MMC-MTDC m+1～P mfor being numbered the power output of current conversion station DC side of m+1～M in MMC-MTDC, m-1 is the total number that adopts the current conversion station of constant DC current control strategy in MMC-MTDC;
A3. adopt Newton-Raphson iterative method to solve above-mentioned nonlinear equation F (U), to obtain direct voltage U 2～U m; Concrete methods of realizing is as follows:
1. the Jacobian matrix that first calculates this Nonlinear System of Equations is as follows:
Figure BDA0000474001860000081
Wherein:
Figure BDA0000474001860000082
it is the diagonal matrix of (M-m) * (M-1) dimension.
2. calculate J (U (k)) △ U (k)=-F (U (k)), wherein
Figure BDA0000474001860000083
be the voltage vector calculating for the k time, U (0)=[U 1..., U 1] t.
3. according to U (k+1)=U (k)+ △ U (k), revise and obtain U (k+1); When | △ U (k)| <10 -5time, think and calculate convergence, stop iteration.
A4. for arbitrary DC power transmission line in MMC-MTDC, make the direct voltage of its two ends current conversion station make the poor voltage in the hope of circuit two ends, thereby and then make this voltage obtain the steady-state current of this circuit divided by the resistance of circuit; Travel through according to this every DC power transmission line.
Direct-current short circuit electric current when present embodiment needs in calculating chart 2 that 1. node breaks down.So first determine that the most serious operating mode is be respectively-3000MW of direct current power and the 0MW that current conversion station 2 and current conversion station 3 inject to DC network.By solving DC network, can obtain the be respectively ± 500kV of stable state direct voltage of current conversion station 1～current conversion station 3, ± 491.101kV and ± 494.915kV, thereby can calculate i in Fig. 2 dc1～i dc6be respectively 1.782kA ,-1.782kA ,-1.273kA, 1.273kA, 1.273kA and-1.273kA.
(2) be illustrated in figure 4 the structural representation of MMC, according to main loop parameter, the MMC in system carried out to equivalent transformation, obtain the passive equivalence circuit that MMC is corresponding.
As shown in Figure 5, passive equivalence circuit is made up of RLC link, and RLC link is composed in series by capacitor C, inductance L and resistance R to output successively from input, the input end grounding of RLC link; Wherein, C=6C 0/ N, L=2L 0/ 3+L s, R=NR 0/ 3; N is the cascade number of MMC brachium pontis change of current submodule, C 0for the electric capacity in change of current submodule, L 0for the brachium pontis reactance of MMC, R 0for the on state resistance of change of current submodule, L sfor the flat ripple reactance of current conversion station.
In present embodiment, every equivalent capacitor C=771 μ F, every equivalent inductance L=112.7mH; Conservative estimation, getting each submodule on-state voltage drop is 0.01 Ω, R=0.2 Ω so.
(3) set up the passive equivalence network of direct current system according to MMC passive equivalence circuit and DC power transmission line; Suppose that considered direct-current short circuit fault betides the direct current outlet bus place (between smoothing reactor and DC line) of current conversion station 1, need to add a voltage source at the respective nodes place of passive equivalence network so, and then this equivalence passive network is carried out to time-domain-simulation, in the hope of every DC power transmission line two ends failure of the current component in MMC-MTDC; The size of voltage source is the stable state direct voltage of this fault point, and symbol is contrary.Consider that the pressure drop in MMC-MTDC DC line is little, and the stable state direct voltage difference at each current conversion station direct current outlet bus place is little, in Practical Calculation, can uses the stable state direct voltage U at current conversion station 1 direct current outlet bus place 1be similar to the size that replaces this voltage source.
For the passive equivalence network that calculates short circuit current fault component as shown in Figure 6.Under time-domain-simulation software, build equivalent network as shown in Figure 6, so for computing node 1.～the 6. fault component of short circuit current.
(4) make the steady-state component of step (1) and step (3) short circuit current of trying to achieve cumulative mutually with fault component, can calculate the short circuit current at circuit two ends.
In order to verify the validity of this patent method, node 1.～6. the result of calculation of short circuit current, as shown in Fig. 7～Figure 12, has comprised result of calculation based on detailed MMC-MTDC model and the contrast of present embodiment result of calculation.(assumed fault betides 6s, only pays close attention to fault the short circuit current within rear 5ms occurs).Result of calculation based on detailed model in comparison diagram 7～Figure 12 and the result of calculation of present embodiment, can find, in considered time range, both difference are very little, and then verified the validity of present embodiment; But consider that the enforcement of present embodiment is based on simplified model, can significantly save computing time and computational resource, therefore present embodiment has very strong engineering practical value.

Claims (6)

1. computational methods for MMC-MTDC dc-side short-circuit electric current, comprise the steps:
(1) control strategy adopting according to current conversion station, carries out sequencing numbers to the each current conversion station in MMC-MTDC, and then according to the operating condition of system and major loop parameter, calculates the steady-state current of every DC power transmission line in MMC-MTDC;
(2), according to the operating condition of system and major loop parameter, each current conversion station in MMC-MTDC is carried out to equivalent transformation to set up the passive equivalence network of MMC-MTDC;
(3) if there is DC power transmission line short trouble in MMC-MTDC, in described passive equivalence network, on the direct current transmission line fault point of correspondence, add a voltage source is set, and then this equivalence passive network is carried out to time-domain-simulation, in the hope of every DC power transmission line two ends failure of the current component in MMC-MTDC;
(4), according to the steady-state current of DC power transmission line and circuit two ends failure of the current component, calculate the short circuit current at every DC power transmission line two ends in MMC-MTDC.
2. computational methods according to claim 1, it is characterized in that: the standard of in described step (1), the each current conversion station in MMC-MTDC being carried out to sequencing numbers is: make to adopt the current conversion station of constant DC voltage control strategy to be numbered 1 in system, make to adopt the current conversion station of constant DC current control strategy to be numbered 2～m in system, make to adopt the current conversion station of determining power control strategy to be numbered m+1～M in system, m-1 is the total number that adopts the current conversion station of constant DC current control strategy in MMC-MTDC, and M is total number of current conversion station in MMC-MTDC.
3. computational methods according to claim 1, is characterized in that: the method for calculating every DC power transmission line steady-state current in MMC-MTDC in described step (1) is as follows:
A1. the direct current voltage equation of setting up MMC-MTDC is as follows:
Figure FDA0000474001850000011
Wherein: the node admittance matrix that Y is MMC-MTDC, I 1～I mthe direct current of exporting for being numbered the current conversion station of 1～M in MMC-MTDC, U 1～U mfor being numbered the direct voltage of current conversion station of 1～M, Y in MMC-MTDC 11, Y 12, Y 21and Y 22be submatrix and Y in node admittance matrix Y 11be 1 × 1 dimension, Y 12be 1 × (M-1) dimension, Y 21for (M-1) × 1 dimension, Y 22for (M-1) × (M-1) dimension, M is total number of current conversion station in MMC-MTDC;
A2. above formula is changed, obtained about direct voltage U 2～U mnonlinear equation F (U) as follows:
F ( U ) = F ( U 2 &CenterDot; &CenterDot; &CenterDot; U M ) = Y 21 U 1 + Y 22 U 2 &CenterDot; &CenterDot; &CenterDot; U M - I 2 &CenterDot; &CenterDot; &CenterDot; I m P m + 1 / 2 U m + 1 &CenterDot; &CenterDot; &CenterDot; P M / 2 U M = 0
Wherein: I 2～I mthe direct current of exporting for being numbered the current conversion station of 2～m in MMC-MTDC, U m+1～U mfor being numbered the direct voltage of current conversion station of m+1～M, P in MMC-MTDC m+1～P mfor being numbered the power output of current conversion station DC side of m+1～M in MMC-MTDC, m-1 is the total number that adopts the current conversion station of constant DC current control strategy in MMC-MTDC;
A3. adopt Newton-Raphson iterative method to solve above-mentioned nonlinear equation F (U), to obtain direct voltage U 2～U m;
A4. for arbitrary DC power transmission line in MMC-MTDC, make the direct voltage of its two ends current conversion station make the poor voltage in the hope of circuit two ends, thereby and then make this voltage obtain the steady-state current of this circuit divided by the resistance of circuit; Travel through according to this every DC power transmission line.
4. computational methods according to claim 1, it is characterized in that: in described step (2), current conversion station is carried out to the specific implementation process of equivalent transformation as follows: make two MMC in current conversion station all equivalence become RLC link, described RLC link is composed in series by capacitor C, inductance L and resistance R successively from input to output, the input common ground of two RLC links; Wherein, C=6C 0/ N, L=2L 0/ 3+L s, R=NR 0/ 3, C 0for the electric capacity in MMC change of current submodule, L 0for the brachium pontis reactance of MMC, R 0for the on state resistance of MMC change of current submodule, L sfor the flat ripple reactance of current conversion station DC side, N is the cascade number of the each brachium pontis change of current of MMC submodule.
5. computational methods according to claim 1, it is characterized in that: in described step (3), definite method of voltage source voltage is as follows: for faulty line, determine the voltage of fault point on this circuit by linear interpolation method according to the direct voltage of its two ends current conversion station, to this voltage negate as the voltage of described voltage source.
6. computational methods according to claim 1, it is characterized in that: in described step (4) for arbitrary DC power transmission line in MMC-MTDC, it is cumulative mutually with the steady-state component of this circuit two ends electric current respectively that the short circuit current at these circuit two ends equals this circuit two ends failure of the current component, and the steady-state component of described circuit two ends electric current is respectively I dcwith-I dc, I dcfor the steady-state current of this circuit; Travel through according to this every DC power transmission line.
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CN109256970A (en) * 2018-09-14 2019-01-22 四川大学 MMC-MTDC transmission system monopolar grounding fault current calculation method
CN109633361A (en) * 2019-01-14 2019-04-16 上海交通大学 Middle straightening stream generator outlet short trouble steady-state current detection method
CN111162562A (en) * 2020-02-04 2020-05-15 华北电力大学 Coordinated fault ride-through method suitable for wind power MMC-MTDC system
CN111327068A (en) * 2020-04-07 2020-06-23 浙江大学 Direct-current side fault voltage calculation method of MMC type direct-current power grid with pseudo-bipolar structure
CN113075440A (en) * 2021-03-29 2021-07-06 国网江苏省电力有限公司经济技术研究院 Power grid short-circuit current calculation method containing flexible direct current transmission system
CN113361886A (en) * 2021-05-28 2021-09-07 西安交通大学 Quantitative evaluation method for interelectrode short-circuit current on direct current side of flexible direct-current power grid
WO2022007232A1 (en) * 2020-07-06 2022-01-13 北京交通大学 Method for calculating steady-state fault current of modular multilevel converter

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CN108933445A (en) * 2018-06-28 2018-12-04 东北电力大学 DC grid short-circuit current calculation method based on the loop method of analysis
CN109256970B (en) * 2018-09-14 2019-11-19 四川大学 MMC-MTDC transmission system monopolar grounding fault current calculation method
CN109256970A (en) * 2018-09-14 2019-01-22 四川大学 MMC-MTDC transmission system monopolar grounding fault current calculation method
CN109633361A (en) * 2019-01-14 2019-04-16 上海交通大学 Middle straightening stream generator outlet short trouble steady-state current detection method
CN111162562A (en) * 2020-02-04 2020-05-15 华北电力大学 Coordinated fault ride-through method suitable for wind power MMC-MTDC system
CN111327068A (en) * 2020-04-07 2020-06-23 浙江大学 Direct-current side fault voltage calculation method of MMC type direct-current power grid with pseudo-bipolar structure
CN111327068B (en) * 2020-04-07 2021-06-29 浙江大学 Direct-current side fault voltage calculation method of MMC type direct-current power grid with pseudo-bipolar structure
WO2022007232A1 (en) * 2020-07-06 2022-01-13 北京交通大学 Method for calculating steady-state fault current of modular multilevel converter
CN113075440A (en) * 2021-03-29 2021-07-06 国网江苏省电力有限公司经济技术研究院 Power grid short-circuit current calculation method containing flexible direct current transmission system
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