CN102708260B - Electromagnetic transient state simulation method and device - Google Patents

Abstract

The invention discloses an electromagnetic transient state simulation method and device, relating to the technical field of time domain simulation of a power system. The method comprises the following steps: setting different simulation steps for child partitions in the current power system respectively, setting the simulation steps of coordination partitions in the current power system to be common divisor of those of the child partitions, and utilizing the simulation steps of the child partitions and the simulation steps of the coordination steps to conduct simulation with the help of an EMTP (electromagnetic transient program) method. By setting different simulation steps for the child partitions in the current power system respectively, the electromagnetic transient simulation efficiency of the power system is improved.

Description

Electromagnetical transient emulation method and device

Technical field

The present invention relates to Power System Time Domain Simulation Under technical field, particularly a kind of electromagnetical transient emulation method and device.

Background technology

As everyone knows, comprehensive, detailed, quickly and accurately the dynamic process of electric system is carried out to analysis and simulation, be the important foundation that ensures power system safety and stability operation.Along with the widespread use of Power Electronic Technique in electric system, increasing dynamic process need to adopt the electromagnetic transient simulation based on detailed modeling and little step-length accurately to portray, and this scale that electric system simulation is calculated expands rapidly.

The main task of electromagnetic transient analysis is the differential algebraic equations group that solves descriptive system dynamic perfromance in discrete moment point, and its Typical Representative is EMTP method.In described EMTP method, by carrying out differencing to describing the dynamic differential equation of element, make each element in system all be expressed as the form of equivalent circuit, and then obtain the equivalent system of original system, its transformational relation is as shown in Figure 1.Through conversion, the dynamic process of original system can be described by the Algebraic Equation set shown in formula (1), by the formula that solves (1) in each discrete moment point, can obtain the time-domain-simulation result of original system.

YU＝I （1）

Wherein, the bus admittance matrix that Y is system, U is node voltage vector, I is node Injection Current vector.

Consider the layering and zoning characteristic on electric system space, spatial parallelism algorithm is used to accelerate electromagnetic transient in power system emulation.Its Typical Representative is the spatial parallelism algorithm based on multiport Dai Weinan equivalence.In Fig. 2, the coordination subregion that system is formed by 6 branch roads is divided into 3 child partitions.The Extended Nodal Voltage Equation of system is as the formula (2):

$\left[\begin{array}{cccc}{Y}_1& 0& 0& P_1\\ 0& Y_2& 0& P_2\\ 0& 0& Y_3& P_3\\ {P_1}^T& {P_2}^T& {P_3}^T& -Z_l\end{array}\right]\left[\begin{array}{c}{U}_1\\ U_2\\ U_3\\ I_l\end{array}\right]=\left[\begin{array}{c}{I}_1\\ I_2\\ I_3\\ -E_l\end{array}\right]---\left(2\right)$

In formula, Y _iit is the bus admittance matrix of each child partition; P _iit is the incidence matrix between the each node of child partition and coordination subregion cutting branch road; I _iit is the node Injection Current vector of child partition; U _iit is the node voltage vector of child partition; I=1,2,3.Z _lfor coordinating the Dai Weinan equiva lent impedance matrix of subregion; E _lit is the Dai Weinan equivalent voltage vector of coordinating subregion; I _lfor cutting branch current vector.

Solve the moment at each, the parallel solution procedure of electro-magnetic transient based on multiport Dai Weinan equivalence can be divided into following 3 steps and complete.

The 1st step: child partition calculates Dai Weinan equivalent parameters

Z _i=P _i ^TY _i ^-1P _i,i＝1,2,3 （1）

E _i＝P _i ^TY _i ^-1I _i,i＝1,2,3 （2）

The 2nd step: coordinate subregion and solve cutting branch current vector

$Z_c=Z_l+\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{Z}_i---\left(5\right)$

$E_c=E_l+\underset{i=1}{\overset{3}{\mathrm{\Σ}}}{E}_i---\left(6\right)$

I _l＝Z _c ^-1*E _c （7）

The 3rd step: child partition solves internal node voltages

U _i＝Y _i ^-1(I _i-P _i*I _l)，i＝1,2,3 （8）

In above-mentioned steps, the 1st step and the 3rd step can parallel processings, and the 2nd step is the serial part in whole solution procedure, wherein, and Z _ifor the Dai Weinan equiva lent impedance matrix of child partition, E _iit is the Dai Weinan equivalent voltage vector of child partition.

It is to be noted, in above-mentioned method for solving, each child partition and coordination subregion all need to adopt identical simulation step length, and this makes the simulation step length of system often be limited by the subregion of dynamic time constant minimum in system, conventionally obtain comparatively conservatively, be unfavorable for the raising of simulation efficiency.In electric system, the dynamic process time scale of each element there are differences, as very fast in power electronic equipment dynamic process, and the dynamic process of the elements such as generator, motor is relatively slow, is a typical rigid system.For the dynamic process of accurate description rigid system, conventionally need to adopt very little step-length to carry out simulation calculation, make the calculated amount of emulation very huge.

Summary of the invention

(1) technical matters that will solve

The technical problem to be solved in the present invention is: the electromagnetic transient simulation efficiency that how to improve electric system.

(2) technical scheme

For solving the problems of the technologies described above, the invention provides a kind of electromagnetical transient emulation method, described method comprises:

Each child partition in current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor of the simulation step length of described each child partition;

Utilize the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation.

Preferably, utilizing the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation specifically comprises:

S1: calculate the Dai Weinan equivalent parameters of described each child partition and described coordination subregion with the simulation step length of described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

S2: utilize the Dai Weinan equivalent parameters of described each child partition and described coordination subregion to calculate the cutting branch current vector of coordinating subregion;

S3: the internal node voltages of utilizing each child partition described in described cutting branch current vector calculation.

Preferably, further comprising the steps of after step S3:

S4: judge whether simulation time reaches home, if so, process ends, otherwise return to step S2.

Preferably, in step S2, calculate the cutting branch current vector of coordinating subregion by following formula,

I _l(t)＝Z _c ^-1(h _c)*E _c(t)，

Wherein, t=mh _c, m is natural number, h _cfor coordinating the simulation step length of subregion; Z _c ^-1(h _c) be Z _c(h _c) inverse, z _i(h _c)=P _i ^ty _i ^-1(h _c) P _i, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _c) for simulation step length be h _ctime, the bus admittance matrix of i child partition, i=1,2,3 ..., N; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; Z _l(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of coordination subregion; Z _i(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of i child partition; E _l(t) coordinate the Dai Weinan equivalent voltage vector of subregion for the t moment; E _i(t) be the Dai Weinan equivalent voltage vector of t moment i child partition; I _l(t) for the t moment is cut branch current vector.

Preferably, E _i(t) determine by following steps:

If the t moment is the integral multiple of i child partition simulation step length, E just _i(t) calculate by following formula,

E _i(t)＝E _i(wh _i)；

If the t moment is also to the integral multiple of i child partition simulation step length, E _i(t) calculate by following formula,

$E_i\left(t\right)=E_i\left[(w-1)h_i\right]+\frac{E_i\left({\mathrm{wh}}_i\right)-E_i\left[(w-1)h_i\right]}{h_i}[t-(w-1)h_i]$

Wherein, t ∈ ((w-1) h _i, wh _i), w is natural number, h _iit is the simulation step length of i child partition.

Preferably, step S3 calculates the internal node voltages of described each child partition by following formula,

U _i(t _n)＝Y _i ^-1(h _i)[I _i(t _n)-P _i*I _l(t _n)]

Wherein, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _i) for simulation step length be h _itime, the bus admittance matrix of i child partition; h _iit is the simulation step length of i child partition; I _l(t _n) be current time t _ntime, cutting branch current vector; t _n=kh _i, k is natural number; I _i(t _n) be current time t _ntime, the node Injection Current vector of i child partition; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; U _i(t _n) be current time t _ntime, the internal node voltages of i child partition.

The invention also discloses a kind of electromagnetic transient simulation device, described device comprises:

Step-length arranges module, and for each child partition of current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor of the simulation step length of described each child partition;

Emulation module, adopts EMTP method to carry out emulation for the simulation step length by described each child partition and described coordination subregion.

Preferably, emulation module specifically comprises:

Calculation of parameter submodule, the Dai Weinan equivalent parameters that calculates described each child partition and described coordination subregion for the simulation step length with described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

Current calculation submodule, calculates for the Dai Weinan equivalent parameters that utilizes described each child partition and described coordination subregion the cutting branch current vector of coordinating subregion;

Node voltage calculating sub module, for utilizing the internal node voltages of each child partition described in described cutting branch current vector calculation.

(3) beneficial effect

The present invention, by each child partition in current power system is arranged respectively to different simulation step length, has improved the electromagnetic transient simulation efficiency of electric system.

Brief description of the drawings

Fig. 1 is the transformational relation schematic diagram of a ball bearing made using and equivalent system thereof;

Fig. 2 is system partitioning schematic diagram;

Fig. 3 is according to the process flow diagram of the electromagnetical transient emulation method of one embodiment of the present invention;

Fig. 4 is according to the structured flowchart of the electromagnetic transient simulation device of one embodiment of the present invention;

Fig. 5 is three partition system schematic diagram of test use;

Fig. 6 is simulation waveform comparison diagram under first group of test parameter;

Fig. 7 is simulation waveform comparison diagram under second group of test parameter;

Fig. 8 is simulation waveform comparison diagram under the 3rd group of test parameter.

Embodiment

Below in conjunction with figure and embodiment, the specific embodiment of the present invention is described in further detail.Following examples are used for illustrating the present invention, but are not used for limiting the scope of the invention.

Fig. 3 is according to the process flow diagram of the electromagnetical transient emulation method of one embodiment of the present invention; With reference to Fig. 3, described method comprises:

Each child partition in current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor (in present embodiment, the simulation step length of described coordination subregion is preferably the highest common factor of the simulation step length of described each child partition) of the simulation step length of described each child partition;

Utilize the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation.

Preferably, utilizing the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation specifically comprises:

S1: calculate the Dai Weinan equivalent parameters of described each child partition and described coordination subregion with the simulation step length of described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

S2: utilize the Dai Weinan equivalent parameters of described each child partition and described coordination subregion to calculate the cutting branch current vector of coordinating subregion;

S3: the internal node voltages of utilizing each child partition described in described cutting branch current vector calculation.

Preferably, further comprising the steps of after step S3:

S4: judge whether simulation time reaches home, if so, process ends, otherwise return to step S2.

Preferably, in step S2, calculate the cutting branch current vector of coordinating subregion by following formula,

I _l(t)＝Z _c ^-1(h _c)*E _c(t)，

Wherein, t=mh _c, m is natural number, h _cfor coordinating the simulation step length of subregion; Z _c ^-1(h _c) be Z _c(h _c) inverse, z _i(h _c)=P _i ^ty _i ^-1(h _c) P _i, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _c) for simulation step length be h _ctime, the bus admittance matrix of i child partition, i=1,2,3 ..., N; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; Z _l(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of coordination subregion; Z _i(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of i child partition; E _l(t) coordinate the Dai Weinan equivalent voltage vector of subregion for the t moment; E _i(t) be the Dai Weinan equivalent voltage vector of t moment i child partition; I _l(t) for the t moment is cut branch current vector.

Owing to coordinating the simulation step length of subregion in described current power system and be set to the common divisor of the simulation step length of described each child partition, therefore existing to coordinate the emulation moment of subregion and also do not reach the situation of the integral multiple of i child partition simulation step length, preferably, E _i(t) determine by following steps:

If the t moment is the integral multiple of i child partition simulation step length, E just _i(t) calculate by following formula,

E _i(t)＝E _i(wh _i)；

If the t moment is also to the integral multiple of i child partition simulation step length, E _i(t) calculate by following formula,

$E_i\left(t\right)=E_i\left[(w-1)h_i\right]+\frac{E_i\left({\mathrm{wh}}_i\right)-E_i\left[(w-1)h_i\right]}{h_i}[t-(w-1)h_i]$

Wherein, t ∈ ((w-1) h _i, wh _i), w is natural number, h _iit is the simulation step length of i child partition.

Preferably, step S3 calculates the internal node voltages of described each child partition by following formula,

U _i(t _n)＝Y _i ^-1(h _i)[I _i(t _n)-P _i*I _l(t _n)]

Wherein, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _i) for simulation step length be h _itime, the bus admittance matrix of i child partition; h _iit is the simulation step length of i child partition; I _l(t _n) be current time t _ntime, cutting branch current vector; t _n=kh _i, k is natural number; I _i(t _n) be current time t _ntime, the node Injection Current vector of i child partition; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; U _i(t _n) be current time t _ntime, the internal node voltages of i child partition.

Fig. 4 is according to the structured flowchart of the electromagnetic transient simulation device of one embodiment of the present invention; With reference to Fig. 4, the invention also discloses a kind of electromagnetic transient simulation system, described system comprises:

Step-length arranges module, and for each child partition of current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor of the simulation step length of described each child partition;

Emulation module, adopts EMTP method to carry out emulation for the simulation step length by described each child partition and described coordination subregion.

Preferably, emulation module specifically comprises:

Calculation of parameter submodule, the Dai Weinan equivalent parameters that calculates described each child partition and described coordination subregion for the simulation step length with described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

Current calculation submodule, calculates for the Dai Weinan equivalent parameters that utilizes described each child partition and described coordination subregion the cutting branch current vector of coordinating subregion;

Node voltage calculating sub module, for utilizing the internal node voltages of each child partition described in described cutting branch current vector calculation.

Embodiment 1

The present embodiment is used for verifying method validity of the present invention, but does not limit protection scope of the present invention, and system is as shown in Figure 5 divided into 3 child partitions and one and coordinates subregion, and child partition numbering is shown in figure and marks.

Adopt the method for present embodiment to carry out following three groups of tests to the system in Fig. 5, in test, the simulation step length of child partition and coordination subregion is as shown in table 1 below:

Each subregion simulation step length parameters in three groups of tests of table 1

Test No.	Coordinate subregion	Child partition 1	Child partition 2	Child partition 3
					1	50us	100us	150us	300us
2	50us	100us	200us	400us
					3	50us	100us	250us	500us

The total duration of emulation is set to 0.1s, for checking the result of correctness to come from business simulation software PSCAD, adopts the simulation step length of 50us to carry out emulation.

In three groups of tests, get the signal of phantom error maximum, the simulation waveform of the method for its PSCAD simulation waveform and present embodiment is put together and contrasted, respectively as shown in Fig. 6 ~ Fig. 8.

From relatively can finding out of simulation waveform, when the method for present embodiment is selected different simulation step length at each subregion, still there is higher accuracy.

Above embodiment is only for illustrating the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; without departing from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (3)

1. an electromagnetical transient emulation method, is characterized in that, described method comprises:

Each child partition in current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor of the simulation step length of described each child partition;

Utilize the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation;

Wherein, utilizing the simulation step length of described each child partition and described coordination subregion to adopt EMTP method to carry out emulation specifically comprises:

S1: calculate the Dai Weinan equivalent parameters of described each child partition and described coordination subregion with the simulation step length of described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

S2: utilize the Dai Weinan equivalent parameters of described each child partition and described coordination subregion to calculate the cutting branch current vector of coordinating subregion;

S3: the internal node voltages of utilizing each child partition described in described cutting branch current vector calculation;

In step S2, calculate the cutting branch current vector of coordinating subregion by following formula,

I _l(t)＝Z _c ^-1(h _c)*E _c(t)，

Wherein, t=mh _c, m is natural number, h _cfor coordinating the simulation step length of subregion; Z _c ^-1(h _c) be Z _c(h _c) inverse, z _i(h _c)=P _i ^ty _i ^-1(h _c) P _i, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _c) for simulation step length be h _ctime, the bus admittance matrix of i child partition, i=1,2,3..., N; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; Z _l(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of coordination subregion; Z _i(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of i child partition; E _l(t) coordinate the Dai Weinan equivalent voltage vector of subregion for the t moment; E _i(t) be the Dai Weinan equivalent voltage vector of t moment i child partition; I _l(t) for the t moment is cut branch current vector;

Wherein, E _i(t) determine by following steps:

If the t moment is the integral multiple of i child partition simulation step length, E just _i(t) calculate by following formula,

E _i(t)＝E _i(wh _i)；

If the t moment is also to the integral multiple of i child partition simulation step length, E _i(t) calculate by following formula,

$E_i\left(t\right)=E_i\left[(w-1)h_i\right]+\frac{E_i\left({\mathrm{wh}}_i\right)-E_i\left[(w-1)h_i\right]}{h_i}[t-(w-1)h_i]$

Wherein, t ∈ ((w-1) h _i, wh _i), w is natural number, h _iit is the simulation step length of i child partition;

In step S3, calculate the internal node voltages of described each child partition by following formula,

U _i(t _n)＝Y _i ^-1(h _i)[I _i(t _n)-P _i*I _l(t _n)]

Wherein, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _i) for simulation step length be h _itime, the bus admittance matrix of i child partition; h _iit is the simulation step length of i child partition; I _l(t _n) be current time t _ntime, cutting branch current vector; t _n=kh _i, k is natural number; I _i(t _n) be current time t _ntime, the node Injection Current vector of i child partition; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; U _i(t _n) be current time t _ntime, the internal node voltages of i child partition.

2. the method for claim 1, is characterized in that, further comprising the steps of after step S3:

S4: judge whether simulation time reaches home, if so, process ends, otherwise return to step S2.

3. an electromagnetic transient simulation device, is characterized in that, described device comprises:

Step-length arranges module, and for each child partition of current power system is arranged respectively to different simulation step length, and the simulation step length of coordinating subregion in described current power system is set to the common divisor of the simulation step length of described each child partition;

Emulation module, adopts EMTP method to carry out emulation for the simulation step length by described each child partition and described coordination subregion;

Wherein, emulation module specifically comprises:

Calculation of parameter submodule, the Dai Weinan equivalent parameters that calculates described each child partition and described coordination subregion for the simulation step length with described each child partition and described coordination subregion, described Dai Weinan equivalent parameters comprises: Dai Weinan equiva lent impedance matrix and Dai Weinan equivalent voltage vector;

Current calculation submodule, calculates for the Dai Weinan equivalent parameters that utilizes described each child partition and described coordination subregion the cutting branch current vector of coordinating subregion;

Node voltage calculating sub module, for utilizing the internal node voltages of each child partition described in described cutting branch current vector calculation;

Wherein, described Current calculation submodule calculates the cutting branch current vector of coordinating subregion by following formula,

I _l(t)＝Z _c ^-1(h _c)*E _c(t)，

Wherein, t=mh _c, m is natural number, h _cfor coordinating the simulation step length of subregion; Z _c ^-1(h _c) be Z _c(h _c) inverse, z _i(h _c)=P _i ^ty _i ^-1(h _c) P _i, Y _i ^-1(h _c) be Y _i(h _c) inverse, Y _i(h _c) for simulation step length be h _ctime, the bus admittance matrix of i child partition, i=1,2,3..., N; P _ithe node and the coordination subregion that are i child partition cut the incidence matrix between branch road; Z _l(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of coordination subregion; Z _i(h _c) for simulation step length be h _ctime, the Dai Weinan equiva lent impedance matrix of i child partition; E _l(t) coordinate the Dai Weinan equivalent voltage vector of subregion for the t moment; E _i(t) be the Dai Weinan equivalent voltage vector of t moment i child partition; I _l(t) for the t moment is cut branch current vector;

Wherein, E _i(t) determine by following steps:

If the t moment is the integral multiple of i child partition simulation step length, E just _i(t) calculate by following formula,

E _i(t)＝E _i(wh _i)；

If the t moment is also to the integral multiple of i child partition simulation step length, E _i(t) calculate by following formula,

$E_i\left(t\right)=E_i\left[(w-1)h_i\right]+\frac{E_i\left({\mathrm{wh}}_i\right)-E_i\left[(w-1)h_i\right]}{h_i}[t-(w-1)h_i]$

Wherein, t ∈ ((w-1) h _i, wh _i), w is natural number, h _iit is the simulation step length of i child partition.