CN106033893A - Method for determining risk degree of influence on inversion stations of alternating-current junction stations - Google Patents

Abstract

The invention discloses a method for determining the risk degree of influence on inversion stations of alternating-current junction stations. The method comprises the following steps that 1, a model of a multi-infeed alternating current-direct current system is established, including n inversion stations and m alternating-current junction stations; 2, disturbance is exerted on one of the inversion stations i, so that the voltage Ui of a converter bus i of the inversion station i is reduced by 1%; 3, based on voltage variations delta Uj of the inversion stations j in the multi-infeed alternating current-direct current system, three-phase multi-infeed interaction factors MIIFij are calculated; 4, based on the scores of the three-phase multi-infeed interaction factors, the risk degree R of a certain inversion station k is calculated; 5, the risk degree R is compared with a reference value (or a standard value) Rstandard, and when the R is greater than or equal to the reference value Rstandard, it is determined that the risk degree of the inversion station is higher than those of common inversion stations. The method has the guiding effect on finding of potential risks of direct-current station commutation failure and formulation of corresponding prevention measures and can also provide reference indexes for direct-current station address selection.

Description

Determine that Inverter Station is by the method exchanging the risk that junction is affected

Technical field

The present invention relates to Power System Analysis field, be specifically related to one and determine in many feed-ins ac and dc systems The method of the risk that Inverter Station is affected by exchange junction.

Background technology

Along with implementing in full of " transferring electricity from the west to the east, north and south supply mutually, on national network " strategy, China just by Step builds up the extra-high voltage AC and DC mixing of the rarest trans-regional and long-distance transmissions great power Transmission system, its complexity and difficulties run the most also is rare.Many feed-ins are handed over straight Stream mixing is by electricity system, due to reinforcement and the increase of power system capacity, the electricity net safety stable of electric network composition Characteristic there occurs that certain change, multi-feed HVDC area are difficult to directly the stable broken of angle of attack unstability Bad thing event, but in the case of lacking enough dynamic reactive power supply supports and other measures, disturbance is sent out Voltage pernicious decline may be caused time raw, cause direct-current commutation failure, ultimately result under serious conditions and be System unstability.

At extensive many feed-ins alternating current-direct current by electricity system, owing between DC inversion station, electrical distance is near, Straight-flow system intercouples, and its direct current and direct current, direct current and the interaction between exchanging are higher, make The response obtaining straight-flow system deteriorates.The commutation failure fault of one current conversion station, may result in other and changes Stream station commutation failure；Under fault in ac transmission system, each DC converter station the most simultaneously or sequentially occurs Commutation failure, if each straight-flow system can not be recovered smoothly, will result in and have a power failure on a large scale.Thus, By analyzing the coupled relation between DC converter station and the relation that influences each other between ac and dc systems, find out The basic law of many feed-ins commutation failure, the weak link in discovery system, and study the weak ring of improvement The technical measures of joint, are highly important for ensureing the safe and stable operation of power system.

Prior art has and judges each DC converter by single-phase many feed-ins interaction factor SMIIF Interaction strong or weak relation between standing, it is intended to by this single-phase many feed-ins interaction factor SMIIF Find out the rule of commutation failure, only consider yet with single-phase many feed-ins interaction factor SMIIF The interaction strong or weak relation of the single-phase voltage between different direct current drop points, additionally, according to " electric power Design of electric engineering handbook ", in Power System Shortcuts Current calculation: conductor and the Dynamic stability of electrical equipment, Thermally-stabilised and the drop-out current of electrical equipment, typically press three-phase shortcircuit and checks.Meanwhile, at DC power transmission system In the simulation analysis of system quasi steady state model, it is assumed that three-phase voltage is symmetrical, for power frequency sine wave.So it is right In the electrical network having multi-feed HVDC, general only consideration three-phase fault simulation analysis.

Summary of the invention

It is an object of the invention to provide one and determine that in many feed-ins ac and dc systems, Inverter Station is by exchange junction The method of the risk of impact, to ensure the safe and stable operation of power system.

For achieving the above object, the invention provides one and determine Inverter Station in many feed-ins ac and dc systems By the method for the risk that exchange junction is affected, comprise the following steps:

(1) building the model corresponding to described many feed-ins ac and dc systems, wherein said many feed-ins are handed over straight Streaming system includes that n Inverter Station exchanges junction with m, and n, m are the positive integer of >=3；

(2) in the model of described many feed-ins ac and dc systems, wherein one exchange junction i is applied Disturbance, i=1,2,3,4 ... m so that the voltage U of the change of current bus of this exchange junction i_iDecline 1%；

(3) based on the voltage variety △ U of Inverter Station j in described many feed-ins ac and dc systems_j, calculate Three-phase mutual factor M IIF of many feed-ins between described exchange junction i and described Inverter Station j_ij, wherein J=1,2,3 ..., n；

(4) based on described many feed-ins mutual factor M IIF score value (score), a certain Inverter Station k is calculated Risk R, wherein risk R for described Inverter Station j by exchange junction i disturbance and occur The risk of fault；

(5) described risk R is compared with reference value (or standard value), so that it is determined that described The risk of one or more Inverter Station in many feed-ins ac and dc systems；Wherein

When described R is more than or equal to described reference value R_standard, then it represents that the risk of this Inverter Station is high In general Inverter Station.

It is preferred that described mutual factor M IIF of many feed-ins_ijIt is calculated as follows:

${\mathrm{MIIF}}_{\mathrm{ij}}=(\mathrm{\Δ}{U}_j/U_j){|}_{\mathrm{\Δ}{U}_i/U_i=1\%}.$

It is preferred that for a certain Inverter Station k, described risk R carry out as the following formula calculating and Judge:

R=∑ MIIF_lk=MIIF_1k+MIIF_2k+…MIIF_mk, wherein l is the most whole less than or equal to m Number.

It is preferred that for a certain Inverter Station k, described risk R is counted in the following manner Calculate and judge:

R is equal to the mutual factor score of many feed-ins of the highest front m1 position in the score value of all MIIF, wherein M1 is arbitrary positive integer of 3-m.

It is preferred that m1 is 2,5,10,15 or m.

It is preferred that when m1 is 2, R_standardIt is 1.5；When m1 is 5, R_tandardIt is 3；Or work as m1 It is 10, R_standardIt is 4.

It is preferred that in step (5), further comprising the steps of: for described Inverter Station k, by single MIIF_lkFactor reference value MIIF mutual with many feed-ins_standardCompare, wherein when there being more than 10 Described single MIIF_lkMore than or equal to described reference value MIIF_standard, then it represents that the wind of this Inverter Station Danger degree is higher than general Inverter Station.

It is preferred that described reference value MIIF_standardIt is 0.3.

It is preferred that for described Inverter Station k, have the single MIIF of more than 30_lkMore than or equal to institute State reference value MIIF_standardTime, then it represents that the risk of this Inverter Station is high risk.

It is preferred that described fault includes that commutation failure, described risk include that described Inverter Station is sent out The risk of raw commutation failure.

The mutual level of factor of the many feed-ins of employing (MIIF) that the present invention proposes determine in many feed-ins ac and dc systems The method of the risk of junction, based on actual electric network model, uses time-domain-simulation to calculate, preferably considers System dynamic characteristic, the voltage coupling that it is showed substantially considered between Inverter Station electrically away from From, effective short-circuit ratio of each change of current bus, actual DC through-put power etc. affect the factor of commutation failure, logical Cross quantizating index, can judge between each direct current station intuitively, direct current with exchange between reciprocal action size close System, it is judged that each Inverter Station of system occurs simultaneously/the probability size of commutation failure and combination that may be present in succession, To finding the potential risk of direct current station commutation failure and formulating corresponding preventive measure and there is certain guidance make With, it is possible to provide a reference index for the direct current siting of station.

Accompanying drawing explanation

Fig. 1 is three infeed HVDC Systems rough schematic views.

Detailed description of the invention

Below with reference to accompanying drawing, presently preferred embodiments of the present invention is described in detail, in order to become apparent from understanding this The objects, features and advantages of invention.It should be understood that embodiment shown in the drawings is not to model of the present invention The restriction enclosed, and simply to illustrate that the connotation of technical solution of the present invention.

Term:

Risk: the probability of Inverter Station generation commutation failure.

Average risk: commutation failure probability is 20%.

High risk: commutation failure probability is 80%.

Commutation failure: be DC transmission system most common failure.The inversion that commutation voltage declines and causes Side DC voltage declines all can with change of current voltage zero-cross point drift when DC current rising, unbalanced fault Having influence on the generation of commutation failure, wherein commutation voltage declines is the main cause causing commutation failure. If once certain current conversion station generation commutation failure, it will cause direct current transportation short interruptions, continuous commutation It also occur that consequences such as DC system lockings during failure, in severe cases it is possible that multiple change There is continuous commutation failure in stream station, even result in mains breakdown simultaneously.Therefore judge and avoid commutation to lose It is very important for losing.

Mutual factor M IIF of many feed-ins is the project planning rank proposed by CIGRE WG B4 working group Section is used for weighing in multi-infeed HVDC system the interactive index of voltage between current conversion station, and its definition is such as Under:

Hypothesis system i.e. exists numbering and is respectively two DC converter stations of 1 and 2, when the change of current is female Line 1 puts into symmetrical three-phase reactor when making the voltage drop on this bus be exactly 1%, change of current bus The change in voltage of 2.That is:

${\mathrm{MIIF}}_{12}=\frac{\mathrm{\Δ}{U}_2\%}{1\%\mathrm{Voltage\; Change\; in}{U}_1}$

Multi-infeed HVDC system drop point concentrates on same AC network, applies to disturb to some current conversion station After Dong, the dynamic response of another current conversion station necessarily contain around here AC system and other current conversion stations to it Common effect.Mutual factor M IIF of many feed-ins is described as a example by three infeed HVDC Systems of Fig. 1 Application in many feed-ins ac and dc systems.

As shown in Figure 1:

$U_2=(\frac{E_2}{X_{N2}}+\frac{U_1}{X_{12}}+\frac{U_3}{X_{23}}-\frac{\sqrt{6}}{\mathrm{\π}}{I}_{d2})\·(\frac{1}{X_{N2}}+\frac{1}{X_{12}}+\frac{1}{X_{23}})$

Wherein, U₁～U₃It is respectively the voltage of change of current bus 1～3；E₁～E₃It is respectively and change of current bus 1～3 Corresponding AC system equivalent electromotive force；X_N1～X_N3It is respectively the exchange system corresponding with change of current bus 1～3 System equiva lent impedance；X₁₂For the coupled impedance between current conversion station 1,2, X₁₃For the coupling between current conversion station 1,3 Close impedance, X₂₃For the coupled impedance between current conversion station 2,3；I_d1～I_d3It is respectively 3 DC power transmission lines Corresponding DC current.

In the case of electric network composition and the method for operation determine, between current conversion station, coupled impedance and AC system wear dimension South equiva lent impedance is certain, i.e.

It is a constant, is designated as X_Σ。

The most rewritable as follows:

$U_2=(\frac{E_2}{X_{N2}}+\frac{U_1}{X_{12}}+\frac{U_3}{X_{23}}-\frac{\sqrt{6}}{\mathrm{\π}}{I}_{d2})\·X_{\mathrm{\Σ}}$

Judge in engineering that commutation failure is usually employing experience voltage criterion, i.e. drop to when commutation voltage Certain threshold value is considered as commutation failure.Assume that commutation voltage just drops into commutation failure threshold value, right The Voltage Drop amplitude answered is △ U2, utilizes superposition theorem to have:

$\mathrm{\Δ}{U}_2=(\frac{\mathrm{\Δ}{E}_2}{X_{N2}}+\frac{\mathrm{\Δ}{U}_1}{X_{12}}+\frac{{\mathrm{\ΔU}}_3}{X_{23}})\·X_{\mathrm{\Σ}}$

General DC current just can significantly rise after commutation failure occurs, and have ignored direct current the most here The change of electric current.From this formula, the commutation failure of Inverter Station is except the exchange being directly attached thereto Outside the impact of system equivalent electric potential source, also affected by Inverter Station voltage coupled thereto, and between them The coefficient of coup from formula, depend on the coupled impedance between each current conversion station and X_∑。

MIIF is as the interactive index of voltage weighed between two Inverter Station, and it is based on actual electric network Model, has considered electrical distance between Inverter Station, effective short-circuit ratio of each change of current bus, actual DC biography The factors such as defeated power, use time-domain-simulation to calculate, and obtained result is relatively individually by exchange Dai Weinan equivalence resistance Disturb and between Inverter Station coupled impedance determine voltage coupling coefficient the most reasonable.

The present inventor, through further investigation and great many of experiments, finds to expand to mutual for many feed-ins factor M IIF Defined below, with investigation exchange junction, the impact of DC converter station can be obtained fabulous effect.Will Mutual factor M IIF of many feed-ins expands to, when ac bus (comprising change of current bus) 1 puts into symmetrical three-phase When reactor makes this busbar voltage fall be exactly 1%, the change in voltage of change of current bus 2.

Use many feed-ins mutual factor M IIF is described below to judge each Inverter Station in many feed-ins ac and dc systems The method of risk.

The method comprises the following steps:

(1) model corresponding to many feed-ins ac and dc systems, wherein this many feed-ins ac and dc systems bag are built Include n Inverter Station and exchange junction with m, and n, m are the positive integer of >=3；

(2) in the model of this many feed-ins ac and dc systems, wherein one exchange junction i is applied disturbance, I=1,2,3,4 ... m so that the voltage U of the change of current bus of this exchange junction i_iDecline 1%；

(3) based on the voltage variety △ U of Inverter Station j in this many feed-ins ac and dc systems_j, calculate exchange pivot Three-phase mutual factor M IIF of many feed-ins between knob station i and Inverter Station j_ij, wherein j=1,2,3 ..., n；

(4) based on these many feed-ins mutual factor M IIF score value (score), the wind of a certain Inverter Station k is calculated Danger degree R；

(5) by risk R and reference value (or standard value) R_standardCompare, so that it is determined that many feed-ins The risk of one or more Inverter Station in ac and dc systems；Wherein

When R is more than or equal to reference value R_standard, then it represents that the risk of this Inverter Station is higher than general inversion Stand.

Wherein, described mutual factor M IIF of many feed-ins_ijIt is calculated as follows:

${\mathrm{MIIF}}_{\mathrm{ij}}=(\mathrm{\Δ}{U}_j/U_j){|}_{\mathrm{\Δ}{U}_i/U_i=1\%}$

(6) for a certain Inverter Station k, risk R calculates as the following formula and judges:

R=∑ MIIF_lk=∑ MIIF_lk=MIIF_1k+MIIF_2k+…MIIF_mk, wherein l is for being less than or equal to The positive integer of m.

(7) for a certain Inverter Station k, risk R also can calculate in the following manner and judge:

R is that in the score value of all MIIF, many feed-ins of the highest front m1 position are mutual for Inverter Station k Factor score, m1 is arbitrary positive integer of 3-m.

It is preferred that m1 is 2,5,10 or m.

When m1 is 2 to be, R_standardIt is 1.5；Or when m1 is 5, R_standardIt is 3；When m1 is 10, R_standardIt is 4.

In step (5), further comprising the steps of: for Inverter Station k, by single MIIF_lkHand over many feed-ins Factor reference value MIIF mutually_standardCompare, as the single MIIF having more than 10_lkMore than or etc. In reference value MIIF_standard, then it represents that the risk of this Inverter Station is higher than general Inverter Station.

It is preferred that reference value MIIF_standardIt is 0.3.

For Inverter Station k, there is the single MIIF of more than 30_lkMore than or equal to described reference value MIIF_standard Time, then it represents that the risk of this Inverter Station is high risk.

Illustrating using Jiangsu Power Grid many feed-ins ac and dc systems as example below to present the employing of the present invention more Send out when entering mutual factor M IIF to determine each Inverter Station in ac and dc systems by the disturbance of each exchange junction The risk of raw fault.

(1) model corresponding to Jiangsu Power Grid many feed-ins ac and dc systems is built, including 5 Inverter Station Junction is exchanged with 113；

(2) wherein one exchange junction i is applied disturbance so that the change of current bus of this exchange junction i Voltage U_iDecline 1%, wherein, i=1,2,3 ... 113；

(3) voltage variety △ Uj based on Inverter Station j, calculates between exchange junction i and Inverter Station j Three-phase mutual factor M IIF of many feed-ins_ij, wherein j=1,2,3,4,5；

(4) based on this mutual factor M IIF of many feed-ins_ijScore value (score), calculates the wind of a certain Inverter Station k Danger degree R；

(5) by risk R and reference value (or standard value) R_standardCompare, determine that many feed-ins are handed over straight The risk of one or more Inverter Station in streaming system；Wherein when R is more than or equal to reference value R_standard, Then represent that the risk of this Inverter Station is higher than general Inverter Station.

(6) for a certain Inverter Station k, risk R can calculate as the following formula and judge:

R=∑ MIIF_lk=MIIF_1k+MIIF_2k+…MIIF_113k, wherein l is the most whole less than or equal to 113 Number,

(7) for a certain Inverter Station k, risk R can calculate as the following formula and judge:

R be for Inverter Station k in the score value of all MIIF many feed-ins of the highest front m1 position mutual because of Sub-score value, m1 is arbitrary positive integer of 3-113.

It is preferred that m1 is 2,5,10 or 113.

When m1 is 2, R_standardIt is 1.5；When m1 is 5, R_standardIt is 3；Or when m1 is 10, R_standard It is 4；When m1 is 113, R_standardIt is 20.

In step (5), further comprising the steps of: for a certain Inverter Station k, risk R also may be used Calculate as the following formula and judge: for Inverter Station k, by single MIIF_lkThe factor mutual with many feed-ins is joined Examine value MIIF_standardCompare, when there being the MIIF more than 10_lkMore than or equal to reference value MIIF_standard, then it represents that the risk of this Inverter Station is higher than general Inverter Station.It is preferred that reference value MIIF_standardIt is 0.3.

For Inverter Station k, have more than or equal to 30 MIIF_lkMore than or equal to reference value MIIF_standard Time, then it represents that the risk of this Inverter Station is high risk.

Table 1 is in Jiangsu Power Grid many feed-ins ac and dc systems between each Inverter Station and each exchange junction MIIF value.

Table 1

Below with in step (6), illustrate when m1 is equal to 113.Now, R=∑ MIIF_lkDeng It is added in all MIIF for each Inverter Station.As can be seen from Table 1, at this point for adverse current station political affairs Flat, risk R is equal to 16.298；For with inner, R is equal to 29.19；For Taizhou 500, R is equal to 28.876； For Taizhou 1000, R is equal to 27.181；For Nanjing, R is equal to 26.924.

Therefore, in Jiangsu Power Grid many feed-ins ac and dc systems, the risk of each Inverter Station sorts from big to small For: put down with ＞ Nanjing, the ＞ Taizhou 1000 ＞ political affairs of inner ＞ Taizhou 500.

And be both greater than 20 with inner, Taizhou 500, Taizhou 1000, risk R in Nanjing, therefore, with inner, Taizhou 500, Taizhou 1000, the risk in Nanjing are higher than general Inverter Station.

With the method for step (7), the risk of each Inverter Station is judged below.

For Inverter Station with inner, Taizhou 500, Taizhou 1000, Nanjing, have 29,33,25,29 respectively Individual MIIF_lkMore than or equal to 0.3, therefore its risk is higher than general Inverter Station.

Additionally, due to there are 33 MIIF in Taizhou 500_lkMore than 0.3, therefore there is high risk in value.

Below presently preferred embodiments of the present invention has been described in detail, it is understood that reading this After bright above-mentioned teachings, the present invention can be made various changes or modifications by those skilled in the art. These equivalent form of values fall within the application appended claims limited range equally.

Claims (10)

1. one kind determines the side of the risk that Inverter Station is affected by exchange junction in many feed-ins ac and dc systems Method, it is characterised in that comprise the following steps:

(1) model corresponding to described many feed-ins ac and dc systems, wherein said many feed-ins alternating current-direct current are built System includes that n Inverter Station exchanges junction with m, and n, m are the positive integer of >=3；

(2) in the model of described many feed-ins ac and dc systems, apply to disturb to wherein one exchange junction i Dynamic, i=1,2,3,4 ... m so that the voltage U of the change of current bus of this exchange junction i_iDecline 1%；

(3) based on the voltage variety △ U of Inverter Station j in described many feed-ins ac and dc systems_j, calculate institute State three-phase mutual factor M IIF of many feed-ins between exchange junction i and described Inverter Station j_ij, wherein j=1, 2,3 ..., n；

(4) based on described many feed-ins mutual factor M IIF score value (score), a certain Inverter Station k is calculated Risk R, wherein risk R is broken down by exchange junction i disturbance for described Inverter Station j Risk；

(5) by described risk R and reference value (or standard value) R_standardCompare, so that it is determined that The risk of one or more Inverter Station in described many feed-ins ac and dc systems；Wherein

When described risk R is more than or equal to described reference value R_standard, then it represents that the wind of this Inverter Station Danger degree is higher than general Inverter Station.

2. the method for claim 1, it is characterised in that described mutual factor M IIF of many feed-ins_ij It is calculated as follows:

${\mathrm{MIIF}}_{\mathrm{ij}}=(\mathrm{\Δ}{U}_j/U_j){|}_{\mathrm{\Δ}{U}_i/U_i=1\%}.$

3. the method for claim 1, it is characterised in that for a certain Inverter Station k, institute Risk R stated calculates as the following formula and judges:

R=∑ MIIF_lk=MIIF_1k+MIIF_2k+…MIIF_mk, wherein l is the most whole less than or equal to m Number.

4. the method for claim 1, it is characterised in that for a certain Inverter Station k, institute Risk R stated calculates in the following manner and judges:

R is equal to the mutual factor score of many feed-ins of the highest front m1 position in the score value of all MIIF, wherein M1 is arbitrary positive integer of 3-m.

5. method as claimed in claim 4, it is characterised in that m1 is 2,5,10 or m.

6. method as claimed in claim 4, it is characterised in that when m1 is 2, R_standardIt is 1.5； When m1 is 5, R_tandardIt is 3；Or when m1 is 10, R_standardIt is 4.

7. the method for claim 1, it is characterised in that in step (5), also include following step Rapid: for described Inverter Station k, by single MIIF_lkFactor reference value MIIF mutual with many feed-ins_standard Compare, wherein as the described single MIIF having more than 10_lkMore than or equal to described reference value MIIF_standard, then it represents that the risk of this Inverter Station is higher than general Inverter Station.

8. method as claimed in claim 7, it is characterised in that described reference value MIIF_standardFor 0.3。

9. method as claimed in claim 7, it is characterised in that for described Inverter Station k, have 30 Above single MIIF_lkMore than or equal to described reference value MIIF_standardTime, then it represents that the wind of this Inverter Station Danger degree is high risk.

10. the method for claim 1, it is characterised in that described fault includes commutation failure, Described risk includes the risk of described Inverter Station generation commutation failure.