CN105842556A - Single-phase parallel capacitor-discharge coil discharge process calculation method - Google Patents

Abstract

The present invention discloses a single-phase parallel capacitor-discharge coil discharge process calculation method. A current method, in which a discharge coil is considered as an inductive element having an inductance value hopping with the current at several segments and constitutes an R-L-C circuit with a capacitor for solving, is not ideal enough in terms of calculation accuracy and speed. The invention establishes a single-phase parallel capacitor-discharge coil discharge loop equivalent circuit through the acquisition of discharge coil winding DC resistance, iron core excitation characteristics and iron core loss equivalent resistance, and achieves the solving for the single-phase parallel capacitor-discharge coil discharge process. The invention considers the impact of the discharge coil non-linear excitation characteristics and iron core loss equivalent resistance, and can more accurately and quickly solve for the single-phase parallel capacitor-discharge coil discharge process.

Description

A kind of parallel single-phase capacitor-discharge coil discharge process computational methods

Technical field

The present invention relates to parallel single-phase capacitor-discharge coil discharge process computational methods, specifically a kind of consideration electric discharge The method calculating parallel single-phase capacitor-discharge coil loop charge discharging resisting process of magnetic bobbin core nonlinear characteristic.

Background technology

The shnt capacitor of isolated neutral system relies on discharge coil to realize the release of residual charge after its separating brake, obtains single Be in parallel capacitor-discharge coil discharge process, it is judged that whether discharge coil meets condenser charge rate of release requirement, right Parallel capacitor device parameter is rationally set, ensures that electric reactive compensating equipment safety operation is significant.

Discharge coil is parallel to capacitor two ends, and during capacitor access system, discharge coil presents high-impedance behavior, capacitor After system disconnects, discharge coil is the most saturated, and resistance value reduces, effective vent discharge container two ends electric charge.Discharge coil ferrum The nonlinear characteristic of the heart, winding directly hinder and core loss is to realize condenser charge release, the key of energy expenditure.

At present, it is achieved calculating parallel single-phase capacitor-the most accurate way of discharge coil discharge process is to be considered as by discharge coil Inductance value, with the inductance element that electric current is several sections of saltus steps, forms R-L-C circuit with Capacitor banks, utilizes R-L-C circuit to resolve Calculating formula, manually calculates and solves.But, this method has certain limitation, does not first consider discharge coil iron core Loss characteristic, secondly utilizes artificial calculating to solve computing capability limited, inductance value can only be reduced to a limited number of section of broken line, Can not fully demonstrate the nonlinear characteristic that discharge coil is unshakable in one's determination, therefore the accuracy in computation of said method, speed are the most not ideal enough.

Summary of the invention

The technical problem to be solved is the defect overcoming above-mentioned prior art to exist, it is provided that one utilizes EMTP to count The method calculating parallel single-phase capacitor-discharge coil discharge process, it is by obtaining discharge coil excitation property, core loss Equivalent resistance, winding D.C. resistance, set up parallel single-phase capacitor-discharge coil discharge loop equivalent circuit, and utilize EMTP Set up corresponding computation model and realize calculating, can be used for shnt capacitor and the selection of discharge coil parameter.

To this end, the technical solution used in the present invention is as follows: a kind of parallel single-phase capacitor-discharge coil discharge process calculating side Method, it comprises the steps:

A) collecting device data, obtains condenser capacity and discharge coil rated voltage；

B) test obtains discharge coil high pressure winding D.C. resistance；

C) setting a series of test voltage, described test voltage is chosen in the 0.1-2 times of range of nominal tension；

D) under a certain test voltage, discharge coil high pressure winding both end voltage and electric current power frequency stable state real-time waveform number are obtained According to, Secondary Winding is opened a way；

E) MATLAB software is utilized to obtain discharge coil exciting current peak value；

F) utilize MATLAB software to be integrated voltage waveform data analyzing, obtain discharge coil high pressure winding magnetic linkage numerical value；

G) repeat the above steps d)-f) test, complete all voltage testers, obtain discharge coil current peak-magnetic linkage numerical value Relation, i.e. excitation property；

H) discharge coil high voltage winding group both end voltage and current wave under voltage are utilized in the 0.8-1.2 times of range of nominal tension at one Shape, obtains core loss equivalent resistance；

I) integrated capacitor capacitance, discharge coil winding D.C. resistance and excitation property thereof and core loss equivalent resistance, build Vertical parallel single-phase capacitor-discharge coil discharge loop equivalent circuit；

J) based on described equivalent circuit, utilize EMTP software to set up parallel single-phase capacitor-discharge coil discharge loop and calculate Model；

K) utilize EMTP software to realize parallel single-phase capacitor-discharge coil discharge process to solve.

The present invention is by obtaining condenser capacity, discharge coil excitation property, core loss equivalent resistance and direct current electricity Resistance, sets up parallel single-phase capacitor-discharge coil discharge loop equivalent circuit and realizes calculating.

Further, in step e), utilize MATLAB software that current waveform data carries out pointwise peak value search, obtain electricity Stream peak value i_max。

Further, in step f), described discharge coil iron core magnetic linkage numerical value ψ_maxWith voltage, current waveform under this test voltage Relational expression is:

${\mathrm{\ψ}}_{max}=\underset{t0-T/4}{\overset{t0}{\∫}}\[u\left(t\right)-r_1\×i\left(t\right)\]dt,$

In formula, u (t) is discharge coil iron core excitation characteristic test gained voltage waveform；I (t) is discharge coil iron core excitation characteristic Test gained current waveform；r₁For discharge coil high pressure winding D.C. resistance；t₀For moment during voltage waveform u (t)=0, T It it is a power frequency period time, for 0.02s.

Further, in step g), described core loss equivalent resistance R₀With voltage, current waveform relation under this test voltage Formula is:

$R_0=\frac{\sqrt{\underset{0}{\overset{T}{\∫}}{\[u\left(t\right)-i\left(t\right)\×r_1\]}^{2}dt}}{\underset{0}{\overset{T}{\∫}}\[u\left(t\right)-i\left(t\right)\×r_1\]i\left(t\right)dt},$

In formula, each meaning of parameters is identical with a upper formula.

Further, step I) in, use nonlinear inductance to characterize the nonlinear characteristic that discharge coil is unshakable in one's determination, its inductance value is with electricity Stream increases and reduces.

Further, step J) in, use type93 element in EMTP software to characterize discharge coil iron-core inductance, Type93 element inputs discharge coil excitation property to characterize its nonlinear characteristic.

Compared with the conventional method, the present invention has taken into full account that the nonlinear characteristic of discharge coil iron core, core loss are to capacitor The impact of-discharge coil discharge process, it is possible to carry out capacitor-discharge coil discharge process the most accurately and rapidly and calculate.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the present invention.

Fig. 2 is equivalent circuit diagram of the present invention.

Fig. 3 is shnt capacitor-discharge coil discharge loop computation model that the present invention sets up based on EMTP.

In the computation model that Fig. 4 is the present invention to be set up based on EMTP, excitation property is set for discharge coil ferromagnetic element.

Fig. 5 is that computational methods of the present invention calculate gained, capacitor voltage at both ends waveform after parallel single-phase capacitor separating brake.

Fig. 6 is that computational methods of the present invention calculate gained, the current waveform of discharge coil after parallel single-phase capacitor separating brake.

Detailed description of the invention

Below in conjunction with specification drawings and specific embodiments, the invention will be further described.

As a example by certain 50HZ electrical network 10kV parallel single-phase capacitor and two ends parallel discharge coil thereof, use the present invention couple below Shnt capacitor-discharge coil loop discharge process calculates, and specifically comprises the following steps that

1. collecting device data, obtaining condenser capacity is 180 μ F, and discharge coil rated voltage is 11kV.

2. discharge coil is carried out D.C. resistance test, obtain its high pressure winding D.C. resistance R=109 Ω.

3. a series of test voltage is set.Test voltage comprises 0.3,0.6,0.9,1.15,1.3,1.6 times of rated voltages.

4. discharge coil high voltage winding group both end voltage, current waveform data under each voltage are obtained.

5. application MATLAB software carries out peak value search to current waveform, as a example by 1.15 times of rated voltage tests, and current wave Shape peak value is 0.135A.

6. voltage waveform is integrated analyzing by application MATLAB software, obtains winding magnetic linkage numerical value, with 1.15 times of specified electricity As a example by pressure test, obtaining magnetic linkage numerical value by formula (1), result is: 36.44Wb.

${\mathrm{\ψ}}_{max}=\underset{t0-T/4}{\overset{t0}{\∫}}\[u\left(t\right)-r_1\×i\left(t\right)\]dt---\left(1\right)$

In formula, u (t) is discharge coil iron core excitation characteristic test gained voltage waveform；I (t) is discharge coil iron core excitation characteristic Test gained current waveform；r₁For discharge coil high pressure winding D.C. resistance；t₀For moment during voltage waveform u (t)=0, T It it is a power frequency period time, for 0.02s.

7. repeat step 4.-step 6., to step 3. in test waveform under all voltages ask for current peak i_maxWith magnetic linkage number Value ψ_max, result is as shown in table 1.

Table 1 excitation curve test result

8. utilize voltage, current waveform under 1.15 times of rated voltages, pick and place the equivalence of electric coil core loss by formula (2) Resistance R₀=6 × 10⁴Ω。

$R_0=\frac{\sqrt{\underset{0}{\overset{T}{\∫}}{\[u\left(t\right)-i\left(t\right)\×r_1\]}^{2}dt}}{\underset{0}{\overset{T}{\∫}}\[u\left(t\right)-i\left(t\right)\×r_1\]i\left(t\right)dt}---\left(2\right)$

In formula, u (t) is discharge coil iron core excitation characteristic test gained voltage waveform；I (t) is discharge coil iron core excitation characteristic Test gained current waveform；r₁For discharge coil high pressure winding D.C. resistance；T is a power frequency period time, for 0.02s.

9. integrated capacitor capacitance, discharge coil winding D.C. resistance and excitation property thereof and core loss equivalent resistance, build Vertical single-phase electricity container-discharge coil discharge loop equivalent circuit, as shown in Figure 2.Wherein nonlinear inductance L_iCharacterize discharge lines Iron-core inductance in circle discharge process, the inductance value under discharge coil iron core difference electric current is determined by excitation property.

10. based on equivalent circuit, EMTP is utilized to set up parallel single-phase capacitor-discharge coil discharge loop computation model such as Fig. 3 Shown in.

Wherein discharge coil iron-core inductance L_iCharacterize with the type93 element of EMTP, type93 element inputs table 1 right Answer excitation property, as shown in Figure 4.

EMTP is utilized to solve, it is thus achieved that capacitor voltage at both ends after single-phase electricity container separating brake, to flow through discharge coil current waveform and divide Not as shown in Figure 5, Figure 6.

Claims (6)

1. parallel single-phase capacitor-discharge coil discharge process computational methods, it comprises the steps:

A) collecting device data, obtains condenser capacity and discharge coil rated voltage；

B) test obtains discharge coil high pressure winding D.C. resistance；

C) setting a series of test voltage, described test voltage is chosen in the 0.1-2 times of range of nominal tension；

D) under a certain test voltage, discharge coil high pressure winding both end voltage and electric current power frequency stable state real-time waveform number are obtained According to, Secondary Winding is opened a way；

E) MATLAB software is utilized to obtain discharge coil exciting current peak value；

F) utilize MATLAB software to be integrated voltage waveform data analyzing, obtain discharge coil high pressure winding magnetic linkage numerical value；

G) repeat the above steps d)-f) test, complete all voltage testers, obtain discharge coil current peak-magnetic linkage numerical value Relation, i.e. excitation property；

H) discharge coil high voltage winding group both end voltage and current wave under voltage are utilized in the 0.8-1.2 times of range of nominal tension at one Shape, obtains core loss equivalent resistance；

I) integrated capacitor capacitance, discharge coil winding D.C. resistance and excitation property thereof and core loss equivalent resistance, build Vertical parallel single-phase capacitor-discharge coil discharge loop equivalent circuit；

J) based on described equivalent circuit, utilize EMTP software to set up parallel single-phase capacitor-discharge coil discharge loop and calculate Model；

K) utilize EMTP software to realize parallel single-phase capacitor-discharge coil discharge process to solve.

Parallel single-phase capacitor the most according to claim 1-discharge coil discharge process computational methods, it is characterised in that In step e), utilize MATLAB software that current waveform data carries out pointwise peak value search, obtain current peak i_max。

Parallel single-phase capacitor the most according to claim 1-discharge coil discharge process computational methods, it is characterised in that In step f), described discharge coil iron core magnetic linkage numerical value ψ_maxWith voltage, current waveform relation under this test voltage it is:

${\mathrm{\ψ}}_{max}=\underset{t0-T/4}{\overset{t0}{\∫}}\[u\left(t\right)-r_1\×i\left(t\right)\]dt,$

In formula, u (t) is discharge coil iron core excitation characteristic test gained voltage waveform；I (t) is discharge coil iron core excitation characteristic Test gained current waveform；r₁For discharge coil high pressure winding D.C. resistance；t₀For correspondence moment, T during voltage waveform u (t)=0 It it is a power frequency period time, for 0.02s.

Parallel single-phase capacitor the most according to claim 1-discharge coil discharge process computational methods, it is characterised in that step In h), described core loss equivalent resistance R₀With voltage, current waveform relation under this test voltage it is:

$R_0=\frac{\sqrt{\underset{0}{\overset{T}{\∫}}{\[u\left(t\right)-i\left(t\right)\×r_1\]}^{2}dt}}{\underset{0}{\overset{T}{\∫}}\[u\left(t\right)-i\left(t\right)\×r_1\]i\left(t\right)dt},$

In formula, u (t) is discharge coil iron core excitation characteristic test gained voltage waveform；I (t) is discharge coil iron core excitation characteristic Test gained current waveform；r₁For discharge coil high pressure winding D.C. resistance；t₀For correspondence moment, T during voltage waveform u (t)=0 It it is a power frequency period time, for 0.02s.

Parallel single-phase capacitor the most according to claim 1-discharge coil discharge process computational methods, it is characterised in that step Rapid I) in, use nonlinear inductance to characterize the nonlinear characteristic of discharge coil iron-core inductance, its inductance value increases with electric current and subtracts Little.

Parallel single-phase capacitor the most according to claim 1-discharge coil discharge process computational methods, it is characterised in that step Rapid J) in, use type93 element in EMTP to characterize discharge coil iron-core inductance, type93 element inputs discharge lines Circle excitation property is to characterize its nonlinear characteristic.