CN103956713B - A kind of protection of direct current supply line configuration setting method considering electromagnetic coupled relation - Google Patents

Abstract

The invention discloses a kind of protection of direct current supply line configuration setting method considering electromagnetic coupled relation, comprise step 1: line fault analysis judges；Step 2: protection starts；Step 3: select pole logic；Step 4: ELIMINATION OF ITS INTERFERENCE；Step 5: edge determination.The present invention is objective and considers the situation that high voltage direct current transmission line fault is likely to occur exactly, and consider between polar curve the impact extremely on normal pole of the fault caused by electromagnetic coupled relation, compensate for existing protection not comprehensively problem, to being adjusted in logic on the basis of being not required to original route protection replacing hardware, engineering availability is strong, improve HVDC transmission line protection to be likely to occur because of electromagnetic coupled relation misoperation capacity of resisting disturbance, and enhance the susceptiveness to line fault and effectiveness, realize the unification of the technical and economy of HVDC transmission line protection engineering, the unification of reliability and sensitivity.

Description

A kind of protection of direct current supply line configuration setting method considering electromagnetic coupled relation

Technical field

The invention belongs to power system field of power transmission, especially relate to a kind of protection of direct current supply line configuration setting method considering electromagnetic coupled relation.

Background technology

Along with the development of China's power industry, high voltage dc transmission technology application in long distance powedr transmission project is more and more extensive.According to statistics, by the end of 2006, the DC transmission engineering that oneself puts into operation all over the world is about 98.The high voltage dc transmission technology of China is just to start starting the eighties in 20th century, but development is very fast.China has 5 in the HVDC engineering built, as shown in table 1-1 at present.Putting into operation in August, 2010 from Zhoushan DC transmission engineering in 1987, China builds the DC transmission engineering put into operation 15.Along with putting into operation of one Guangdong, south electric network in June, 2010 Yunnan ± 800kV extra-high voltage direct-current engineering and in July, 2010 national grid Burner zone one Shanghai ± 800kV extra-high voltage direct-current engineering, China has become and has had that electric pressure in the world is the highest, transmission capacity is maximum, the country of technical merit state-of-the-art extra-high voltage direct-current transmission engineering.

Electromagnetic coupled is there is between DC line, coupled relation between each polar conductor produces to straight-flow system steady-state operation and have a strong impact on, only in the case of straight-flow system generation disturbance, as circuit occurs earth fault etc., the transient state component that fault produces can be because the cause influences such as electromagnetic coupled relation and line parameter circuit value imbalance be to other properly functioning polar conductors.The Electric Power Network Planning stage to DC power transmission line between electromagnetic coupled relation considered complete, often between circuit, electromagnetic coupled relation can cause the electromagnetic coupled misoperation between circuit, brings great challenge to DC transmission system safe and reliable operation.Tianguang HVDC power transmission engineering from calendar year 2001 bipolar put into operation since 4 bipolar locking accidents occurring, the accident such as " 8.19 " cloud wide extra-high voltage direct-current bipolar locking all and between circuit electromagnetic coupled there is certain relation.

In DC power transmission line actual motion, the arrangement mode between transmission line of electricity can make to there is multiple electromagnetic coupled relation between circuit, and the fault that circuit can suffer from, such as: thunder and lightning direct attack, thunderbolt, low resistance grounding fault, high resistance earthing fault etc..The produced circuit transient swing when side line fault, all by the impact corresponding on normal side generation of the electromagnetic coupled relation between circuit and can cause fluctuation to whole DC transmission system, become an important content of direct current transportation operation maintenance work.

In a prior art situation, hvdc transmission line protection also exists electromagnetic coupled relation between polar curve inconsiderate, to the normal pole misoperation caused by electromagnetic coupled and the problem of straight-flow system poor reliability.DC operation referenced during the DC transmission system design used at present is lacked experience; circuit practical situation considers the most abundant; and on relaying configuration, also exist that means are simple, sensitivity is low, the problem of poor reliability; because of the DC system locking etc. caused by electromagnetic coupled, all DC transmission system is existed serious impact.

Summary of the invention

The present invention is directed to the defect of above-mentioned prior art; propose the protection of direct current supply line configuration setting method considering electromagnetic coupled relation, solve in prior art mesohigh HVDC protection technology the fault caused by electromagnetic coupled relation between polar curve and extremely normal pole to be affected problem.

The present invention takes into full account the situation that various lines fault is likely to occur, and is specifically included that railroad section fault by circuit operating space, is arranged the typical fault that may bring under inverter side reverse fault, AC bus and line fault and various disturbance；The faults such as the interference of back flashover, thunderbolt, thunder and lightning, metallic earthing, high resistance ground are specifically included that by fault type.Consider that different faults has different reaction acting characteristics, in addition it is also necessary in view of electromagnetic coupled relation between polar curve.In concrete configuration, effectively have been directed to the electromagnetic coupled impact on transmission system between probability and the DC power transmission line that fault occurs, complete paired fault is held targeted specifically.The present invention uses as starting point using Practical Project; with the impact caused by electromagnetic coupled relation between consideration polar curve; making protection can successfully manage electromagnetic coupled relation is main purpose; efficiently solve because of the electromagnetic coupled relation protection misoperation problem to the generation of DC transmission system, make the protection system can sensitive, action quickly and efficiently.

For realizing object above, this invention takes following technical scheme: a kind of protection of direct current supply line considering electromagnetic coupled relation configures setting method, comprises the steps:

Step one: line fault analysis judges, determines HVDC transmission line type, the fault corresponding by this circuit of straight-flow system identification；

Step 2: relay protective scheme starts, by gathering the voltage variety signal of DC power transmission line existing protection installation place, calculates voltage jump amount, if exceeding enabling gate threshold value, then starting protection logic enters next step；

Its criterion is:

In formula, i represents the positive and negative polarities of DC power transmission line, i=1,2；R and I represents rectification side and inverter side respectively；k_RAnd k_IIt is respectively line commutation side and the enabling gate threshold value of inverter side Protection criteria.

Its protection of direct current supply line constituted judge formula as

In formula, i, j represent the positive and negative polarities of double back DC power transmission line, i=1,2,3,4；J=1,2,3,4；j≠i；M represents signal is carried out Wavelet transformation process；R and I represents rectification side and inverter side respectively；k_R1For the two poles of the earth, line commutation side voltage jump amount ratio setting valve；MΔi_Ri, M Δ i_IiRepresent Δ i respectively_Ri, Δ i_IiWavelet modulus maxima；sign(MΔi_Ri), sign (M Δ i_Ii) represent M Δ i respectively_Ri, M Δ i_IiPolarity；sign(MΔu_Ri) represent Δ u_RiThe polarity of wavelet modulus maxima；Δu_RiWith Δ u_RjRepresent rectification side i pole and j polar curve road voltage variety respectively；△i_RiWith △ i_IiRepresent rectification side and inverter side i polar curve road current change quantity respectively；

Step 3: select pole logic, after relay protective scheme starts, protection starts to calculate the ratio of the two poles of the earth voltage jump amount, if ratio is more than k_R1, then explanation fault extremely this pole, for double-circuit line, enter step 4 ELIMINATION OF ITS INTERFERENCE；Single back line is then proceeded to relay protective scheme, if the two poles of the earth voltage jump amount ratio is more than k_R2, this explanation DC line there occurs thunderbolt interference, protect involution；If but the two poles of the earth voltage jump amount ratio is not less than k_R2, then break down on explanation circuit, enter step 5 and carry out edge determination；

K described in step 3_R1For the two poles of the earth voltage jump amount ratio setting valve, k_R2For single back line relay protective scheme for distinguishing thunderbolt interference and the voltage jump amount ratio setting valve of lightning fault；

Step 4: ELIMINATION OF ITS INTERFERENCE, protection is to △ u_RiCarrying out wavelet transformation, obtain the modulus maximum of wavelet transformation under the 5th yardstick (dB5), if it is negative, explanation is thunder and lightning interference, protects involution, but if just, then illustrates it is not thunder and lightning interference, enter edge determination；

Step 5: edge determination, protection is read rectification side and inverter side current signal, and current signal is carried out wavelet transformation, and judges whether to start route protection according to the polarity of the modulus maximum of both sides wavelet transformation；If the wavelet modulus maxima opposite polarity of both sides electric current, start route protection, otherwise protect involution.

Wherein: distinguish in means and method mainly determine fault thunderbolt and interference thunderbolt, AC fault and commutation failure, route protection district according to the difference of voltage jump amount for single time and common-tower double-return direct current transmission line fault and external area error etc. described in step one.

It is the parameter value k for combining concrete engineering parameter and operating experience is manually set that voltage jump amount described in step 2 exceedes definite value_RAnd k_I, the respectively enabling gate threshold value of line commutation side and inverter side Protection criteria.

Wavelet transformation described in step 4 refer to based on the wavelet transformation under the 5th yardstick obtained by modulus maximum.

It is the current change quantity signal gained by gathering protection installation place that protection described in step 5 reads rectification side with inverter side current signal.

The present invention compared with prior art, has the advantage that

1, objective and consider the situation that high voltage direct current transmission line fault is likely to occur exactly, and consider between polar curve the impact extremely on normal pole of the fault caused by electromagnetic coupled relation, compensate for existing protection not comprehensively problem；

2, only need to be adjusted original route protection in logic, only need to revise software logic without changing hardware, engineering availability is strong；

3, on the premise of ensureing protection act reliability; improve HVDC transmission line protection to be likely to occur because of electromagnetic coupled relation misoperation capacity of resisting disturbance; and enhance the susceptiveness to line fault and effectiveness, it is achieved HVDC transmission line the protection unification of technical and economy of engineering, the unification of reliability and sensitivity.

Accompanying drawing explanation

Accompanying drawing 1 reacts schematic diagram for HVDC transmission system multiple faults；

Accompanying drawing 2 is to consider the protection of direct current supply line collocation method figure of electromagnetic coupled relation between polar curve.

Detailed description of the invention

With detailed description of the invention, present disclosure is described in further details below in conjunction with the accompanying drawings.

Embodiment:

As it is shown in figure 1, learnt by engineering operation experience, the failure problems being likely to occur in HVDC transmission system has: line side fault F1 and F2；Rectification side bus or current conversion station fault F_R；Change of current side bus or current conversion station fault F_I.Concrete consider whole DC system fault time, it is considered to line fault need to make a distinction according to distance on line side and circuit, wherein line fault is according to away from rectification side distance 0%；35%；65%；100% is divided into F1_1, F1_2, F1_3, F1_4.From line fault place, polarity is divided into F1 and F2.After fault occurs; usually can go out existing ripple and transient overvoltage etc. on the line; the capacity effect existed between hvdc transmission line; will make to produce between circuit electromagnetic coupled relation, the voltage waveform of the acute variation of fault side all can close through electromagnetic coupled and tie up to the normal side corresponding interference waveform of generation.Consider the most abundant for current line electricity magnetic coupling under existing protection system, it is impossible to its impact on whole DC transmission system of effective sensitive reply.

It is illustrated in figure 2 and considers the protection of direct current supply line collocation method figure of electromagnetic coupled relation between polar curve.Consider that between polar curve, the protection of direct current supply line collocation method of electromagnetic coupled relation is to consider under multiple possible breakdown; between consideration polar curve, the possible misoperation perfected caused by the impact of pole is affected by the fault caused by electromagnetic coupled relation; and in order to react under premise the most delicately, the maximally effective solution put forward.Configuration figure shown in fig. 2, main collocation method has been divided into five parts: step 1, step 2, step 3, step 4 and step 5, is respectively shown in judging for line fault analysis, protection starts, selects pole logic, ELIMINATION OF ITS INTERFERENCE and edge determination.

In step 1 line fault analysis judges, the different different electromagnetic coupled relations caused by DC power transmission line arrangement mode of main consideration, main fault distinguish determines that means are as follows:

A. consider that between single time DC power transmission line, the fault of electromagnetic coupled relation determines:

1), when breaking down on single time DC power transmission line, the voltage variety of fault pole is maximum, determines therefrom that fault pole；

2) polarity of electric current modulus maximum after wavelet transformation is not affected by transition resistance, and can utilize the electric current wavelet modulus maxima polarity of rectification side and inverter side, gets rid of DC line external area error.

3) in the case of DC power transmission line is struck by lightning, fault thunderbolt has been above 2 with the fault pole tension Sudden Changing Rate of interference thunderbolt, in the case of fault thunderbolt, the ratio of the two poles of the earth voltage jump amount is less than 3.2 more than 2.5, and in the case of interference is struck by lightning, the ratio of the two poles of the earth voltage jump amount is more than 3.5.Therefore exclusive PCR thunderbolt can be carried out by the two poles of the earth voltage jump amount.When occurring AC earth fault or AC fault to cause the faults such as direct-current commutation failure outside DC line, voltage jump amount ratio is 1, therefore can get rid of AC fault and commutation failure with the ratio of the two poles of the earth voltage jump amount simultaneously.

B. consider that between double back DC power transmission line, the fault of electromagnetic coupled relation determines:

1), when breaking down on a DC power transmission line wherein, the voltage variety of fault pole is maximum, can determine fault pole whereby.Owing to fault pole is both greater than 2 with the voltage jump amount ratio on other three loop lines road, and during AC fault, owing to the equipment on straight-flow system transmission line of electricity is arranged symmetrically with, its voltage jump amount ratio is 1, so AC fault, commutation failure can be got rid of with the ratio of voltage Sudden Changing Rate.

2) polarity of electric current modulus maximum after wavelet transformation is not affected by transition resistance, and can utilize the electric current wavelet modulus maxima polarity of rectification side and inverter side, gets rid of DC line external area error.

3) in the case of fault thunderbolt, the modulus maximum of the wavelet transformation of the voltage of fault pole is just；When there is interference thunderbolt, the wavelet modulus maxima of the voltage of disturbance pole is negative, it is possible to utilize voltage wavelet modulus maxima to get rid of thunder and lightning interference.

According to the fault determination method of electromagnetic coupled relation between considerations above polar curve, effectively take into account the electromagnetic coupled impact on whole DC transmission system between the limit, can effectively distinguish and determine fault.

In step 2 protection starts, protecting the voltage variety signal by gathering protection of direct current supply line installation place, calculate voltage jump amount, if exceeding enabling gate threshold value, then starting protection logic enters next link.Additionally the main criterion of protection institute foundation is:

In formula, i represents the positive and negative polarities of DC power transmission line, i=1,2；k_RAnd k_IIt is respectively line commutation side and the enabling gate threshold value of inverter side Protection criteria.The ratio size utilizing the voltage variety amplitude that two-wire line records can be with Judging fault pole and get rid of AC fault, the situation such as commutation failure and thunderbolt interference；Whether the polarity utilizing the modulus maximum of the wavelet multi-scale analysis of jump-value of current is contrary, in can distinguishing DC line protection district and external area error；The polarity utilizing the modulus maximum of the wavelet multi-scale analysis of voltage jump amount can get rid of thunderbolt interference.According to this, may be constructed protection of direct current supply line criterion:

In formula, i, j represent the positive and negative polarities of double back DC power transmission line, i=1,2,3,4；J=1,2,3,4；j≠i；M represents signal is carried out Wavelet transformation process；R and I represents rectification side and inverter side respectively；k_R1For the two poles of the earth, line commutation side voltage jump amount ratio setting valve；M△i_Ri, M △ i_IiRepresent △ i respectively_Ri, Δ i_IiWavelet modulus maxima；sign(MΔi_Ri), sign (M Δ i_Ii) represent M Δ i respectively_Ri, M Δ i_IiPolarity；

sign(MΔu_Ri) represent Δ u_RiThe polarity of wavelet modulus maxima；Δu_RiWith Δ u_RjRepresent rectification side i pole and j polar curve road voltage variety respectively；Δi_RiWith Δ i_IiRepresent rectification side and inverter side i polar curve road current change quantity respectively.

In step 3 selects pole logic, after relay protective scheme starts, protection starts to calculate the ratio of the two poles of the earth voltage jump amount, if ratio is more than k_R1, then explanation fault extremely this pole.For double-circuit line, enter step 4 ELIMINATION OF ITS INTERFERENCE；Single back line is then proceeded to relay protective scheme, if the two poles of the earth voltage jump amount ratio is more than k_R2, i.e. there occurs thunderbolt interference on DC line, protect involution.If but the two poles of the earth voltage jump amount ratio is not less than k_R2, then break down on explanation circuit, enter step 5 edge determination.

In step 4 ELIMINATION OF ITS INTERFERENCE, protection is to Δ u_RiCarrying out wavelet transformation, obtain the modulus maximum of wavelet transformation under the 5th yardstick, if it is negative, explanation is thunder and lightning interference, protects involution, but if just, then illustrates it is not thunder and lightning interference, enter edge determination.

In step 5 edge determination, rectification side and inverter side current signal are read in protection, and current signal carries out wavelet transformation, and judge whether to start route protection according to the polarity of the modulus maximum of both sides wavelet transformation.If the wavelet modulus maxima opposite polarity of both sides electric current, start route protection, otherwise protect involution.

Above-listed detailed description is illustrating for possible embodiments of the present invention, and this embodiment is also not used to limit the scope of the claims of the present invention, and all equivalences done without departing from the present invention are implemented or change, are intended to be limited solely by the scope of the claims of this case.

Claims (2)

1. the protection of direct current supply line configuration setting method considering electromagnetic coupled relation, it is characterised in that Comprise the steps:

Step one: line fault analysis judges, determines HVDC transmission line type, straight-flow system knows The fault that this circuit is not corresponding；

Step 2: relay protective scheme starts, becomes by gathering the voltage of DC power transmission line existing protection installation place Change amount signal, calculates voltage jump amount, if exceeding enabling gate threshold value, then starting protection logic enters next step Suddenly；

Its criterion is:

$\left\{\begin{array}{c}\left|\mathrm{\Δ}{u}_{Ri}\right|>k_R\\ \left|{\mathrm{\Δu}}_{Ii}\right|>k_I\end{array}\right.$

In formula, i represents the positive and negative polarities of DC power transmission line, i=1 (+), 2 (-)；R and I represents rectification side respectively And inverter side；k_RAnd k_IIt is respectively line commutation side and the enabling gate threshold value of inverter side Protection criteria；

Its protection of direct current supply line constituted judge formula as

$\left\{\begin{array}{c}\left|\mathrm{\Δ}{u}_{Ri}\right|/\left|\mathrm{\Δ}{u}_{Rj}\right|>k_{R1}\\ q=sign\left({\mathrm{M\Δu}}_{Ri}\right)=-1\\ p=sign\left(M\mathrm{\Δ}{i}_{Ri}\right)\×sign\left(M\mathrm{\Δ}{i}_{Ii}\right)=-1\end{array}\right.,$

In formula, i, j represent the positive and negative polarities of double back DC power transmission line, i=1,2,3,4；J=1,2,3,4；j≠i；M Represent and signal is carried out Wavelet transformation process；R and I represents rectification side and inverter side respectively；k_R1Whole for circuit Stream the two poles of the earth, side voltage jump amount ratio setting valve；MΔi_Ri, M Δ i_IiRepresent Δ i respectively_Ri, Δ i_IiSmall echo become Die change maximum；sign(MΔi_Ri), sign (M Δ i_Ii) represent M Δ i respectively_Ri, M Δ i_IiPolarity； sign(MΔu_Ri) represent Δ u_RiThe polarity of wavelet modulus maxima；Δu_RiWith Δ u_RjRepresent rectification side respectively I pole and j polar curve road voltage variety；Δi_RiWith Δ i_IiRepresent that rectification side and inverter side i pole line current become respectively Change amount；

Step 3: select pole logic, after relay protective scheme starts, protection starts to calculate the two poles of the earth voltage jump amount Ratio, if ratio is more than k_R1, then explanation fault extremely this pole, for double-circuit line, enter step 4 interference Get rid of；Single back line is then proceeded to relay protective scheme, if the two poles of the earth voltage jump amount ratio is more than k_R2, There occurs thunderbolt interference on this explanation DC line, protect involution；If but the two poles of the earth voltage jump amount ratio is not More than k_R2, then break down on explanation circuit, enter step 5 and carry out edge determination；Described k_R2For single time Route protection logic is for distinguishing thunderbolt interference and the two poles of the earth voltage jump amount ratio setting valve of lightning fault；

Step 4: ELIMINATION OF ITS INTERFERENCE, protects right+u_RiCarry out wavelet transformation, obtain the wavelet transformation under the 5th yardstick Modulus maximum, if it is negative, explanation is thunder and lightning interference, protects involution, but if just, then illustrates not It is thunder and lightning interference, enters edge determination；

Step 5: edge determination, protection is read rectification side and inverter side current signal, and is entered current signal Row wavelet transformation, and judge whether to start route protection according to the polarity of the modulus maximum of both sides wavelet transformation； If the wavelet modulus maxima opposite polarity of both sides electric current, start route protection, otherwise protect involution.

2. the protection of direct current supply line configuration side of adjusting considering electromagnetic coupled relation as claimed in claim 1 Method, it is characterised in that: it is by adopting with inverter side current signal that rectification side is read in the protection described in step 5 The current change quantity signal gained of collection protection installation place.