CN104331550A - Smoothing reactor broadband electromagnetic transient analysis equivalent circuit based on transmission line structures - Google Patents

Abstract

The invention relates to a smoothing reactor broadband electromagnetic transient analysis model based on transmission line structures, in particular to a smoothing reactor broadband electromagnetic transient analysis equivalent circuit based on transmission line structures which belongs to the field of electromagnetic transient broadband models for power systems. n like smoothing reactor unit length broadband equivalent circuits are sequentially connected in series to form the equivalent circuit provided by the invention, so that a plurality of distributed transmission line structures are formed, and the distributed transmission line structures are utilized to simulate the transmission of the transient wave process in a smoothing reactor. The smoothing reactor broadband electromagnetic transient analysis equivalent circuit takes the changes of parasitic capacitance, stray inductance and winding resistance of distribution parameters of the smoothing reactor under the high-frequency skin effect and the proximity effect into consideration, and can accurately simulate the electromagnetic transient of the smoothing reactor under power frequency characteristics and disturbance characteristics.

Description

Based on the smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit of transmission line structure

Technical field

The invention belongs to electromagnetic transient in power system wideband model field, in particular to a kind of broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure, consider the change of the stray capacitance of smoothing reactor distribution parameter under high frequency skin effect and approach effect effect, stray inductance and winding resistance, be applicable to electromagnetic transient analysis and the DC fields Conducted Electromagnetic harassing and wrecking horizontal analysis of DC transmission system smoothing reactor.

Background technology

Smoothing reactor is one of major equipment in HVDC converter substation, is the key equipment connecting converter valve and DC side.The accuracy of smoothing reactor wideband equivalent-circuit model directly has influence on the validity of DC fields Conducted Electromagnetic harassing and wrecking level calculation, then has influence on the accuracy of DC fields spatial electromagnetic harassing and wrecking horizontal forecast.

Smoothing reactor forms the direct current harmonic loop of HVDC converter substation DC side together with DC filter, can prevent the steep wave superpotential produced by DC line or DC switch station from entering the valve Room, thus make converter valve avoid suffering superpotential stress and damaging; Ripple in smoothing reactor energy smooth direct current electric current, can avoid the interrupted of when the transmission of low DC power electric current; It can reduce commutation failure rate by the current changing rate of restriction caused by quick voltage changes simultaneously.

Smoothing reactor comprises dry reactor and oily formula reactor two kinds, and in high voltage power transmisson system, the smoothing reactor of dry type and oily formula all obtains at ± 500 kV HVDC converter substations and adopts, and ± 800 kV HVDC converter substations adopt dry smoothing reactor.Under high frequency, skin effect and approach effect can cause the rising of winding resistance and the decline of inductance, and meanwhile, the stray capacitance of distribution parameter will be can not ignore in high frequency.As shown in Figure 1, wherein high-pressure side interface H is positioned at reactor top to the primary structure of typical smoothing reactor, and low pressure end interface L is positioned at reactor bottom, and whole smoothing reactor is positioned on the platform of distance ground certain altitude, and earth potential is labeled as GND.Ground (i.e. zero-potential point) is considered as a terminal, then whole smoothing reactor can be considered three-terminal network, and three terminals are respectively H, L, GND.

In series only by an inductance or inductance and fixed value resistance of existing smoothing reactor equivalent-circuit model, be applicable to power frequency condition, not considering the change of winding resistance, inductance and electric capacity under high frequency characteristics, therefore can produce larger error when analyzing harassing and wrecking characteristic.

In order to electro-magnetic transient characteristic and the DC fields Conducted Electromagnetic harassing and wrecking level of accurate analysis smoothing reactor, should accurately consider stray parameter frequency dependent characteristic.In transient state is propagated and electromagnetic disturbance propagation is analyzed, the stray inductance between smoothing reactor winding turns line and stray capacitance can produce a very large impact smoothing reactor transmission characteristic, are therefore necessary the distribution situation for each circle line research stray parameter.And on smoothing reactor equivalent-circuit model whole structure under power frequency condition and harassing and wrecking condition in ensure the accuracy of the model calculation.

Summary of the invention

The object of the invention is the weak point for overcoming prior art, a kind of smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure is proposed, the present invention is based on smoothing reactor unit length equivalent circuit, consider the stray capacitance of smoothing reactor distribution parameter under high frequency skin effect and approach effect effect, the change of stray inductance and winding resistance, solve the problem that existing reactor model can not meet electromagnetic transient analysis under harassing and wrecking condition, in the electromagnetic transient analysis and DC fields Conducted Electromagnetic harassing and wrecking horizontal analysis of DC transmission system smoothing reactor, there is outstanding advantage.

The smoothing reactor transmission line structure broadband electromagnetical transient analysis equivalent electrical circuit that the present invention proposes, its theoretical foundation is the wave process describing the inner transient state of smoothing reactor, be equivalent to transmission line model, respectively research unit's length equivalent circuit stray parameter, just can the propagation in the windings of accurate description ripple and the distribution of voltage between winding.Adopt circuit component to simulate smoothing reactor transient state process, can realize in circuit analysis platform easily, under power frequency condition and harassing and wrecking condition, all there is very high accuracy.

A kind of smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure that the present invention proposes, it is characterized in that, this equivalent electrical circuit is in series successively by n identical smoothing reactor unit length wideband equivalent electrical circuit, form multiple distributed transmission line structure, by the propagation of the inner transient state wave process of this distributed transmission line structure simulation smoothing reactor;

The number n of this smoothing reactor unit length wideband equivalent electrical circuit, the research length corresponding with unit length wideband equivalent electrical circuit according to the flat anti-winding equivalent length of smoothing reactor is divided by and is obtained.

Described each smoothing reactor unit length wideband equivalent electrical circuit comprises a resistance per unit length R ₀, a unit length inductance L ₀, a unit length turn-to-turn stray capacitance C _s0with two unit length stray capacitance C over the ground _s0; Wherein, resistance per unit length R ₀with unit length inductance L ₀series connection, unit length turn-to-turn stray capacitance C _s0two ends respectively with resistance per unit length R ₀, unit length inductance L ₀the other end be connected, unit length turn-to-turn stray capacitance C _s0with resistance per unit length R ₀with unit length inductance L ₀form parallel-connection structure; First unit length stray capacitance C over the ground _g0one end and resistance per unit length R ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the first unit length stray capacitance C over the ground _g0other end ground connection; Second unit length stray capacitance C over the ground _g0one end and unit length inductance L ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the second unit length stray capacitance C over the ground _g0other end ground connection;

Wherein, L ₀, R ₀obtained by formula (1) according to the resistance R of reactor and inductance L:

R ₀＝R/L _en，L ₀＝L/L _en(1)

L _enfor the flat anti-winding equivalent length of smoothing reactor;

The capacitance C of smoothing reactor _s, C _cgvand C _cglcarry out obtaining end-to-end and end high frequency characteristics measurement result over the ground before dispatching from the factory from smoothing reactor, C _sfor total turn-to-turn capacitance, C _cgvand C _cglrepresent smoothing reactor valve side and net side stray capacitance measurement result over the ground respectively, then calculate unit length stray capacitance C over the ground by formula (2) _g0, unit length turn-to-turn is spuious:

$C_{g0}=\frac{C_{\mathrm{cgv}}+C_{\mathrm{cgl}}}{4*L_{\mathrm{en}}},C_{s0}=L_{\mathrm{en}}*C_s---\left(2\right).$

The present invention sets up the principle of equivalent electrical circuit: due to high-pressure side over the ground, low pressure end over the ground, high-pressure and low-pressure end short circuit earth impedance frequency characteristic is all presented as capacitance characteristic, and impedance frequency characteristic is presented as inductance and Capacitance parallel connection characteristic between high-pressure side and low pressure end, the impedance frequency characteristic between two terminals is measured respectively by electric impedance analyzer, again in conjunction with reactor theoretical empirical, set up characterize reactor high frequency characteristics equivalent-circuit model as Fig. 2, abstract is that high frequency equivalent circuit model is as Fig. 3.In Fig. 2-Fig. 3, C _hhigh-pressure side stray capacitance over the ground, C _lthat low pressure end is to spuious ground electric capacity.

Because smoothing reactor is to the height of ground level much larger than reactor self, high-pressure side is stray capacitance C over the ground _hwith low pressure end stray capacitance C over the ground _lshould be substantially equal.Also need to consider the inner transient state process of smoothing reactor in harassing and wrecking characteristic, transmission line model is adopted to carry out equivalence inner for smoothing reactor transient state process, smoothing reactor entirety is represented with some distributed wideband equivalent electrical circuit, overall for smoothing reactor stray parameter equalization is assigned in distributed wideband equivalent electrical circuit, on circuit topological structure, distributed wideband equivalent electrical circuit is consistent with entirety external wideband equivalent electrical circuit, then some distributed equivalent electrical circuit are coupled together, form the overall equivalent electrical circuit of smoothing reactor.

Compared with original smoothing reactor equivalent electrical circuit, advantage of the present invention is as follows:

1) consider the frequency dependent characteristic of smoothing reactor winding turns line stray capacitance, stray inductance, adopt transmission line structure equivalence smoothing reactor, smoothing reactor electro-magnetic transient can be simulated, in power frequency and harassing and wrecking frequency range, all there is very pin-point accuracy.

2) smoothing reactor inner winding turns line stray parameter can be simulated by circuit component, and computation process is simply efficient.

3) DC transmission system smoothing reactor Partial DC field Conducted Electromagnetic harassing and wrecking computational problem can be solved simultaneously.

Accompanying drawing explanation

Fig. 1 is typical smoothing reactor primary structure schematic diagram.

Fig. 2 is the overall high frequency equivalent circuit model schematic of smoothing reactor.

Fig. 3 is the abstract overall high frequency equivalent circuit of this smoothing reactor.

Fig. 4 is smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit of the present invention.

Fig. 5 is smoothing reactor of the present invention distributed unit length wideband equivalent electrical circuit.

Embodiment

The smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure that the present invention proposes is described in detail as follows:

The present invention proposes a kind of smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure, it is characterized in that, be in series successively by n identical smoothing reactor unit length wideband equivalent electrical circuit, form multiple distributed transmission line structure, as shown in Figure 4, in figure 1,2,3 ..., square frame that n is corresponding represents a distributed smoothing reactor unit length wideband equivalent electrical circuit respectively, the connecting line at square frame two ends shows the series relationship between unit length wideband equivalent electrical circuit.The propagation of the inner transient state wave process of smoothing reactor can be simulated like this by distributed transmission line structure.

The number n of this smoothing reactor unit length wideband equivalent electrical circuit, the research length corresponding with unit length wideband equivalent electrical circuit according to the flat anti-winding equivalent length of smoothing reactor (please explain any implication, another each element below all has unit length also please explain what implication, each circle coil of corresponding reactor) being divided by obtains, here research length refers to the needs according to Study on Problems, the smoothing reactor umber of turn that each unit length wideband equivalent electrical circuit is corresponding, the wideband equivalent electrical circuit that each umber of turn is corresponding is exactly the unit length studied in this situation, if not otherwise indicated, unit length refers in particular to smoothing reactor one circle coil.

As shown in Figure 5, this equivalent electrical circuit comprises a resistance per unit length R to the concrete structure of described each smoothing reactor unit length wideband equivalent electrical circuit ₀, a unit length inductance L ₀, a unit length turn-to-turn stray capacitance C _s0with two unit lengths stray capacitance (for distribution parameter electric capacity) C over the ground _s0; Wherein, resistance per unit length R ₀with unit length inductance L ₀series connection, unit length turn-to-turn stray capacitance C _s0two ends respectively with resistance per unit length R ₀, unit length inductance L ₀the other end be connected, unit length turn-to-turn stray capacitance C _s0with resistance per unit length R ₀with unit length inductance L ₀form parallel-connection structure; First unit length stray capacitance C over the ground _g0one end and resistance per unit length R ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the first unit length stray capacitance C over the ground _g0other end ground connection; Second unit length stray capacitance C over the ground _g0one end and unit length inductance L ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the second unit length stray capacitance C over the ground _g0other end ground connection; Such smoothing reactor winding turns line stray capacitance, stray inductance are embodied by the circuit component in wideband equivalent electrical circuit, the impact of high frequency skin effect and approach effect is embodied by the change of electric capacity, inductance and resistance value, computation process simplifies greatly, and has frequency dependent characteristic under harassing and wrecking characteristic.

Wherein, L ₀, R ₀obtained by formula (1) according to the resistance R of reactor and inductance L:

R ₀＝R/L _en，L ₀＝L/L _en(1)

L _enfor the flat anti-winding equivalent length of smoothing reactor;

The capacitance C of smoothing reactor _s, C _cgvand C _cglcarry out obtaining end-to-end and end high frequency characteristics measurement result over the ground before dispatching from the factory from smoothing reactor, C _sfor total turn-to-turn capacitance, C _cgvand C _cglrepresent smoothing reactor valve side and net side stray capacitance measurement result over the ground respectively, then calculate unit length stray capacitance C over the ground by formula (2) _g0, unit length turn-to-turn is spuious:

$C_{g0}=\frac{C_{\mathrm{cgv}}+C_{\mathrm{cgl}}}{4*L_{\mathrm{en}}},C_{s0}=L_{\mathrm{en}}*C_s---\left(2\right)$

Below one embodiment of the present of invention, test 500kV DC transmission system smoothing reactor stray parameter, this embodiment design parameter is as follows:

Test product title	Dry-type hollow smoothing reactor	Test product model	PKK-500-3200-100
				System voltage	500kV	Rated voltage	500kV
Highest operating voltage	515kV	Rated current	3200A
				Maximum continuous DC current	3556A	Short-time current	36kA 0.2s
Inductance ratings	100mH	The number of phases	Single-phase
				The type of cooling	AN	Impact dielectric level	950kV
Insulation grade anti-corrosion	H	To dispatch from the factory sequence number	238696
				Manufacturing firm	Beijing Electrical Equipment Factory	Build date	In February, 2012

This smoothing reactor equivalent electrical circuit is divided into 4 distributed equivalent electrical circuit, and each distributed equivalent circuit parameter is as follows: R ₀=12m Ω, L ₀=35mH, C _s0=1960pF and C _g0=190pF.

This equivalent circuit impedance characteristic and actual measurement impedance operator are contrasted, the power frequency characteristic within the scope of 10 ~ 1MHz and harassing and wrecking characteristic overlap substantially, and accuracy is very high.

For dry type and oil immersed type smoothing reactor, its main circuit structure is similar, but its parameter there are differences, and can adopt the dissimilar smoothing reactor of the mutually isostructural equivalent circuit description of the present invention, but parameter will be selected according to corresponding specification.

Claims (2)

1. the smoothing reactor broadband electromagnetical transient analysis equivalent electrical circuit based on transmission line structure, it is characterized in that, this equivalent electrical circuit is in series successively by n identical smoothing reactor unit length wideband equivalent electrical circuit, form multiple distributed transmission line structure, by the propagation of the inner transient state wave process of this distributed transmission line structure simulation smoothing reactor;

The number n of this smoothing reactor unit length wideband equivalent electrical circuit, the research length corresponding with unit length wideband equivalent electrical circuit according to the flat anti-winding equivalent length of smoothing reactor is divided by and is obtained.

2. equivalent electrical circuit as claimed in claim 1, it is characterized in that, described each smoothing reactor unit length wideband equivalent electrical circuit comprises a resistance per unit length R ₀, a unit length inductance L ₀, a unit length turn-to-turn stray capacitance C _s0with two unit length stray capacitance C over the ground _s0; Wherein, resistance per unit length R ₀with unit length inductance L ₀series connection, unit length turn-to-turn stray capacitance C _s0two ends respectively with resistance per unit length R ₀, unit length inductance L ₀the other end be connected, unit length turn-to-turn stray capacitance C _s0with resistance per unit length R ₀with unit length inductance L ₀form parallel-connection structure; First unit length stray capacitance C over the ground _g0one end and resistance per unit length R ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the first unit length stray capacitance C over the ground _g0other end ground connection; Second unit length stray capacitance C over the ground _g0one end and unit length inductance L ₀with unit length turn-to-turn stray capacitance C _s0tie point be connected, the second unit length stray capacitance C over the ground _g0other end ground connection;

Wherein, L ₀, R ₀obtained by formula (1) according to the resistance R of reactor and inductance L:

R ₀＝R/L _en，L ₀＝L/L _en(1)

L _enfor the flat anti-winding equivalent length of smoothing reactor;

The capacitance C of smoothing reactor _s, C _cgvand C _cglcarry out obtaining end-to-end and end high frequency characteristics measurement result over the ground before dispatching from the factory from smoothing reactor, C _sfor total turn-to-turn capacitance, C _cgvand C _cglrepresent smoothing reactor valve side and net side stray capacitance measurement result over the ground respectively, then calculate unit length stray capacitance C over the ground by formula (2) _g0, unit length turn-to-turn is spuious:

$G_{g0}=\frac{C_{\mathrm{cgv}}+C_{\mathrm{cgl}}}{4*L_{\mathrm{en}}},C_{s0}=L_{\mathrm{en}}*C_s---\left(2\right).$