CN110492448A - The distance protecting method of route is sent out suitable for new energy station - Google Patents
The distance protecting method of route is sent out suitable for new energy station Download PDFInfo
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- CN110492448A CN110492448A CN201910624417.8A CN201910624417A CN110492448A CN 110492448 A CN110492448 A CN 110492448A CN 201910624417 A CN201910624417 A CN 201910624417A CN 110492448 A CN110492448 A CN 110492448A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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Abstract
The invention discloses a kind of distance protecting methods that route is sent out suitable for new energy station, comprising: the voltage and current data before and after measurement failure in a period of time；According to fault type, fault point high frequency voltage is calculated using the data measured；Route will be sent out and be divided into I section of distance and II section of distance, calculate separately the high-frequency work voltage of I section of distance with II section of distance；If I section of distance of high-frequency work voltage is not less than fault point high frequency voltage, adjusts the distance I section and carry out distance protection；If II section of distance of high-frequency work voltage is not less than fault point high frequency voltage, after postponing a period of time, according to the maximum value of sample rate current in a time window and the size of electric current threshold value about to determine whether adjusting the distance II section carries out distance protection.This method can accurately distinguish fault zone, and then realize distance protection.
Description
Technical field
The present invention relates to Power System Analysis technical field more particularly to a kind of route is sent out suitable for new energy station
Distance protecting method.
Background technique
With energy crisis, environmental pollution, greatly developing new energy becomes the important development direction of China's energy strategy.By
It is typically remote from load center in China's solar energy, wind energy area abundant, scale new energy concentration is sent outside as inexorable trend.
Therefore, the correct movement for sending out route protection is significant for new energy safety grid-connection.Distance protection is compared since it has
Stable protection scope, influenced by system operation mode it is small, therefore be usually used in send out route as back-up protection.
Influence of the scale new energy access for distance protection is mainly reflected in two aspects, first is that the weak feedback of new energy
The influence of effect.The weak feedback effect of inverse type power supply can cause the influence of transition resistance to be amplified, so as to cause station lateral extent
Relay fail.In addition, crow bar investment can enhance the weak feedback characteristic of double-fed blower.Second is that the influence of harmonic wave and frequency shift (FS).Have
A large amount of harmonic waves and the power frequency offset injected when person's qualitative analysis wind power integration extract power frequency component to fourier algorithm
It influences, has obtained the conclusion of power frequency quantity distancing element action performance decline.In addition document also derives revolving speed frequency component to complete
All fourier algorithms extract the expression formula that power frequency quantity causes error, disclose revolving speed frequency component for the affecting laws of measurement impedance.
After crow bar investment, double-fed blower station side is power-frequency voltage and revolving speed frequency electric current, obtains measurement impedance according to its ratio Analysis
Helically formula changes for track, seriously affects the reliability of distance protection.Additionally, due to new energy positive-negative sequence impedance by operation side
The influence of the factors such as formula, fault condition and change, power frequency variation distance protection action performance can also be decreased obviously.
The research that domestic and foreign scholars send out route distance protection for new energy station at present has been achieved with certain progress.
For the weak feedback effect of new energy, there is scholar to point out to can permit the protection deferred action of station lateral extent, allows system side breaker
Leading tripping, weak feedback event resolves at this time, lateral extent protection in station can be acted correctly, but such a process increases Fault Isolations
Time.Collect system exchange side line road for DC boosting, injects four-time harmonic elimination in failure by changing control mode
Weak feedback problem when phase-to phase fault, but this method control system is complex.For frequency offset issues, there is scholar to propose base
In the time domain distance protection of model identification thought, but single order local derviation meeting influence from harmonic, action performance are slightly worse.Power frequency is changed
Distance protection is measured, has document report by method of the change power frequency variation apart from protection seting value, prevents the rearward impedance to be in
False protection when reverse direction failure occurs in the case where capacitive, however new energy impedance operator is changeable, the method for modifying definite value exists
New energy sends out route and is difficult to be applicable in, it is therefore necessary to study the new distance protecting method for being suitable for new energy station.
Summary of the invention
The object of the present invention is to provide a kind of distance protecting methods that route is sent out suitable for new energy station, can be accurate
Fault zone is distinguished, and then realizes distance protection.
The purpose of the present invention is what is be achieved through the following technical solutions:
A kind of distance protecting method for sending out route suitable for new energy station, comprising:
Measure the voltage and current data in failure front and back a period of time；
According to fault type, fault point high frequency voltage is calculated using the data measured；
Route will be sent out and be divided into I section of distance and II section of distance, calculate separately the high-frequency work of I section of distance with II section of distance
Voltage；If I section of distance of high-frequency work voltage is not less than fault point high frequency voltage, adjusts the distance I section and carry out distance protection；If away from
High-frequency work voltage from II section is not less than fault point high frequency voltage, then after postponing a period of time, according to comparing a time window
The size of the maximum value of sample rate current and electric current threshold value in long, to judge whether II section of distance act.
As seen from the above technical solution provided by the invention, it can use the high frequency of I section of distance and II section of distance
Operating voltage is come accurately to distinguish fault zone with the size relation of the fault point high frequency voltage of construction, and then it is dynamic to generate protection
Make；Entire plan plot is clear, and execution efficiency is high, has good action performance.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, required use in being described below to embodiment
Attached drawing be briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, for this
For the those of ordinary skill in field, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is a kind of stream of distance protecting method that route is sent out suitable for new energy station provided in an embodiment of the present invention
Cheng Tu；
Fig. 2 is unit step signal provided in an embodiment of the present invention and its amplitude spectrum schematic diagram；
Fig. 3 is the main topological structure schematic diagram of inverse type power supply provided in an embodiment of the present invention；
Fig. 4 is four kinds of high-frequency resistance structural schematic diagrams of inverse type power supply provided in an embodiment of the present invention；
Fig. 5 is new energy high-frequency resistance unified structure schematic diagram provided in an embodiment of the present invention；
Fig. 6 is the main topological structure schematic diagram of double-fed blower provided in an embodiment of the present invention；
Fig. 7 is the high-frequency resistance structural schematic diagram of double-fed blower provided in an embodiment of the present invention；
Fig. 8 is new energy station main electrical scheme schematic diagram provided in an embodiment of the present invention；
Fig. 9 is high frequency fault network diagram provided in an embodiment of the present invention；
High frequency voltage distribution schematic diagram when Figure 10 is different faults point short circuit provided in an embodiment of the present invention；
Figure 11 is impedance circle characteristic schematic diagram provided in an embodiment of the present invention；
Figure 12 is the high-frequency resistance angle schematic diagram of inverse type power supply provided in an embodiment of the present invention；
Figure 13 is the high-frequency resistance angle schematic diagram of double-fed fan motor unit provided in an embodiment of the present invention；
Figure 14 is the impedance value schematic diagram provided in an embodiment of the present invention calculated using virtual faults voltage；
Figure 15 is the performance schematic diagram of I sections provided in an embodiment of the present invention protection；
Figure 16 is the performance schematic diagram of I sections provided in an embodiment of the present invention protection；
Figure 17 is transition resistance provided in an embodiment of the present invention to I sections of influence schematic diagram；
Figure 18 is transition resistance provided in an embodiment of the present invention to II sections of influence schematic diagram.
Specific embodiment
With reference to the attached drawing in the embodiment of the present invention, technical solution in the embodiment of the present invention carries out clear, complete
Ground description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.Based on this
The embodiment of invention, every other implementation obtained by those of ordinary skill in the art without making creative efforts
Example, belongs to protection scope of the present invention.
The embodiment of the present invention provides a kind of distance protecting method that route is sent out suitable for new energy station, as shown in Figure 1,
It is specifically included that
1, the voltage and current data before and after measurement failure in a period of time.
Illustratively, the voltage and current data of measurement failure front and back 5ms can be measured.
2, according to fault type, fault point high frequency voltage is calculated using the data measured.
Since fault point high frequency voltage can not be measured directly, in the embodiment of the present invention, utilize protection installation place voltage
The fault point high frequency voltage for going construction equivalent.Specifically:
Fault point high frequency voltage be by Voltage Drop before failure point failure to 0 generate, and before failure point failure voltage with
Protect installation place failure before voltage it is of substantially equal, thus can use protection installation place failure before Voltage Drop to 0 generate height
Frequency voltage removes the high frequency voltage of equivalent fault point.
For singlephase earth fault, each variable is the high frequency voltage and high-frequency current of failure phase, is mutually protected using failure
Phase voltage drops to 0 before the failure that installation place measures, and then extracts to obtain using wavelet transformation；For phase fault, Vk=
Vkφ1-Vkφ2, Vw=Vwφ1-Vwφ2, Iw=Iwφ1-Iwφ2, wherein φ 1 and φ 2 is two failure phases, and installation is mutually protected using failure
Line voltage before the failure that place measures drops to 0 construction；VkFor fault point high frequency voltage, VwAnd IwProtection installation place measures
High frequency voltage and high-frequency current.
3, route will be sent out and is divided into I section of distance and II section of distance, calculate separately the high frequency work of I section of distance with II section of distance
Make voltage；If I section of distance of high-frequency work voltage is not less than fault point high frequency voltage, adjusts the distance I section and carry out distance protection；If
II section of distance of high-frequency work voltage is not less than fault point high frequency voltage, then after postponing a period of time, according to comparing a time
The maximum value of sample rate current and the size of electric current threshold value in window is long, (act in jump to judge whether II section of distance protection acts
Lock).
In the embodiment of the present invention, the calculation formula of I section of the distance and II section of distance of high-frequency work voltage are as follows:
Wherein, VwIt is the high frequency voltage for protecting installation place to measure；The respectively high frequency of I section of distance, II section of distance
Operating voltage；
For I section of setting valve of distance: For II section of setting valve of distance:Wherein,For I section of safety factor, f is institute's selected frequency；L is the full inductance for sending out route.
Since the high-frequency signal that failure generates can detect only in the time window comprising instant of failure, and away from
Setting time from II section is usually 0.3~0.5s, and delay time may be configured as 0.3~0.5s；It will be unable at the end of delay
Compare the size of fault point high frequency voltage and operating voltage.To solve the above problems, in failure, it is necessary to whether judge fault point
Within II section of protection scope, then differentiate whether failure still has after 0.3~0.5s by increasing assistant criteria.If
Failure still has, and II section of distance will act excision failure.
Assistant criteria can use non-faulty current composition.If because failure is already cut off before delay terminates,
So new energy will no longer export fault current, therefore amplitude criterion are as follows:
imax> iop
Wherein imaxFor in a time window, the maximum value of sample rate current；iopFor electric current threshold value, it can be taken as 5%~
10% rated current peak value.
In order to make it easy to understand, the principle below for above scheme does detailed introduction.
When an error occurs, Voltage Drop can be seen as the step signal injected in fault point, in Fig. 2
(a) shown in part, for step signal, it can be found that it is with full range domain information, such as Fig. 2 after Laplace transform
In the part (b) shown in.And this high-frequency signal can be extracted by wavelet transformation.Illustratively, the data window of extraction is long
For 10ms, include the 5ms data after failure.
Inverse type new energy mainly includes photo-voltaic power supply and permanent magnet direct-drive blower, passes through inverter direct grid-connected, and
LCL filter is installed in inverter outlet, main topology is as shown in Figure 3.C in Fig. 3dFor DC bus capacitor, R1、R2、R3、L1、L2、
C is LCL filter inner parameter.
According to inverter under different switch combinations, the access that high-frequency current flows through can determine the high frequency of inverse type power supply
Impedance model has a variety of impedance structures, as shown in figure 3, showing schematically four kinds of impedance structures.Four kinds of impedance structures remove
Except part in dotted line frame is different, rest part is identical.It and is part and R in dotted line frame1、L1Series connection, then
With filter capacitor branch circuit parallel connection, most followed by R2、L2Series connection.Under normal conditions, for inductance and capacitive branch in parallel, as long as electric
The capacitive reactance of appearance is less than 1/10th of inductance induction reactance connected in parallel, then inductive branch connected in parallel can be omitted.From inverse type
As long as the alternate high-frequency resistance structure of four of power supply can be seen that inductance L1Capacitive reactance of the induction reactance value greater than ten times of capacitor 2C
Value, four kinds of impedance structures can be unified for structure as shown in Figure 5.Therefore, unified for alternate high-frequency resistance structure, it should select
The frequency range selected are as follows:
In the frequency range for meeting above formula, the impedance value of filter capacitor branch is at least the ten of branch impedance connected in parallel
1/5th or 1/20th.Therefore, the branch in parallel with filter capacitor can be ignored, and four kinds of impedance structures are unified for attached
Fig. 5, wherein R=R2+R3.In addition, high frequency channel is the part deleted in box, while will be oval for singlephase earth fault
Frame inner part is transferred to branch connected in parallel.At this time for four kinds of impedance structures are unified, institute's selected frequency should meet:
Convolution (1)~formula (2) is it is found that only solemnity (2) is satisfied, four in the case of different faults kind impedance structure
To be unified.
In unified structure, R=R2+R3.In order to enable mentioned method sensitivity with higher, the impedance of unified structure
Angle should be greater than 60 °.Therefore, selected frequency should also meet:
In addition, in order to avoid the influence of control system, selected frequency necessarily is greater than the bandwidth of electric current loop, based on above-mentioned
Factor, it is determined that lower-frequency limit.Meanwhile the upper limit of frequency is preferably lower than 3kHz.Mainly consider to obtain good noise
Than the limitation of measuring unit and data processing board and the influence in order to avoid system parasitic capacitor.
The main topology of double-fed fan motor unit asynchronous generator and its rotor-side parallel branch as shown in fig. 6, be mainly made of.
The high frequency Equivalent Model of its singlephase earth fault is made of asynchronous generator Equivalent Circuit and filter capacitor branch, as shown in Figure 7.
R in figures、LsThe respectively resistance and inductance of asynchronous generator stator side, Rr、LrFor asynchronous generator rotor side resistance and inductance,
LmFor the excitation reactance of asynchronous generator, C is the capacitance of filter capacitor, RCrowarRepresent Crowbar resistance.When double-fed blower
Crowbar device when not putting into, there is no dotted line frame inner part in high frequency model, be herein in short-circuit condition.Once
Crowbar device investment, has just sealed in Crowbar resistance in high frequency model.
It is similar to inverse type power supply, when the capacitive reactance of filter capacitor C is less than the equivalent reactance of asynchronous generator connected in parallel
1/10th when, asynchronous motor equivalence branch can be ignored, therefore selected frequency range should meet:
Under conditions of institute's selected frequency meets formula (4), the high-frequency resistance model equivalence of double-fed blower is filter capacitor C, so
And due to main transformer, collect the influence that route and case become, sense is still presented sending out the high-frequency resistance angle measured at line outlet
Character state, to make its high-frequency resistance angle be greater than 60 °, selected frequency range should be verified by formula (3), but wherein R is equal to main transformer, case
Become and the sum of the resistance for collecting route, L2Equal to the sum of main transformer, case change and the inductance for collecting route.
By above-mentioned analysis, inverse type power supply and the high-frequency resistance model of double-fed blower can be waited in selected high band
Effect is RL series loop, it is believed that with line impedance phase characteristic having the same, therefore can be realized in high frequency network
Sudden Changing Rate distance protecting method.
New energy sends out the main topology of route as shown in figure 8, new energy power supply is sent out after being collected by case change boosting through main transformer.
It is as shown in Figure 8 in the high frequency fault network for sending out route generation metallicity failure.ZkFor (the protection installation of short dot to W bus
Place) HF link impedance, ZLFor whole high-frequency resistance for sending out route, ZwAnd ZsRespectively station side and system equivalent high frequency
Impedance, VwAnd IwIt is the high frequency voltage and high-frequency current measured at W bus, VkIt is generated when metallic short circuit occurs for fault point
High frequency voltage source.Do not consider fault point first there are transition resistances to protect the high-frequency electrical of installation place according to the reference direction in figure
Flow IwWith high frequency voltage VwIt can respectively indicate are as follows:
Assuming that ZsetFor I sections of definite value of distance protection, it is taken as the 80%~85% of route high-frequency resistance, then can construct height
Frequency operating voltage are as follows:
Vop=Vw-IwZset=-Iw(Zs+Zset) (7)
And the high frequency voltage V of fault pointkIt can indicate are as follows:
Vk=-Iw(Zs+Zk) (8)
It is distributed according to high frequency voltage when formula (7) and formula (8) available different location short circuit, as shown in Figure 9.From Fig. 9
As can be seen that only troubles inside the sample space when meet:
|Vop|≥|Vk| (9)
It therefore can be by comparing high-frequency work voltage VopWith the high frequency voltage V of fault pointkSize relation distinguish area in
Outer failure.It is worth noting that, calculation formula (8) etc. is only intended between analysis fault point high frequency voltage and high-frequency work voltage
Relationship, and in practical projects, the high frequency voltage of fault point cannot be measured directly, it is therefore necessary to utilize protection installation place electricity
The fault point high frequency voltage that pressure goes construction equivalent.Since fault point high frequency voltage is produced by Voltage Drop before failure point failure to 0
Raw, and voltage and voltage before protection installation place failure are of substantially equal before failure point failure, therefore can use protection installation place
The high frequency voltage that Voltage Drop is generated to 0 before failure removes the high frequency voltage of equivalent fault point.
For singlephase earth fault, each variable in above-mentioned analysis is the high frequency voltage and high-frequency current of failure phase.It is right
In phase fault, Vk=Vkφ1-Vkφ2, Vw=Vwφ1-Vwφ2, Iw=Iwφ1-Iwφ2, φ 1 and φ 2 are two failure phases.
It, can by Fig. 9 and high-frequency work voltage and fault point voltage calculation method when fault point is there are when transition resistance
:
|Vop|=|-Iw(Zw+Zset) |=|-Iw||Zw+Zset| (10)
|Vk|=|-Iw(Zw+Zk)-αIwRg|=|-Iw||Zw+Zm (11)
Wherein: α is that high frequency helps increasing coefficient,
Formula (10) and (11) are substituted into formula (9), the operation equation of impedance circle can be obtained are as follows:
|Zw+Zset|≥|Zw+Zm| (12)
The impedance circle characteristic as shown in part (a) in Figure 11 (positive direction failure) can be drawn according to above formula.Due to failure
Point two sides high-frequency resistance is all close to 90 °, two sides electric current IwAnd IsSame-phase, so additional impedance α RgIt is approximately purely resistive, together
When two sides electric currents size relation be only dependent upon the size of two sides high-frequency resistance, therefore do not influenced by failure limiter.In addition,
The radius of impedance circle is larger in high frequency, and α RgIt is unrelated with frequency, therefore this method has stronger anti-transition resistance ability,
And frequency is higher, the ability of anti-transition resistance is stronger.The impedance circle characteristic of this method, such as Figure 11 when can similarly obtain reverse direction failure
In shown in the part (b).As can be seen from the figure this method can guarantee that the criterion opposite direction is reliably motionless.In figure
ZLFor the high-frequency resistance of total track length.
In the embodiment of the present invention, this method still uses two-part distance protection protection circuit overall length.I section of distance is used as quick-action
Duan Tongchang accounts for the 80%~85% of protection circuit overall length, so its setting valve can indicate are as follows:
Wherein,For I section of safety factor, can value be 0.8~0.85；F is institute's selected frequency；L is the complete of submitting route
Inductance.
For II section of distance, protection scope usually with junior route protection I sections match, due to the topology studied herein
There is no junior's routes, therefore the route high-frequency resistance for being 1.1 times by the adjusting of II sections of distance of setting valve:
In practical applications, I section and II section of setting valve is converted into high-frequency work voltageWithFormula can be found in
Above and the part Fig. 1.
Since the high-frequency signal that failure generates can detect only in the time window comprising instant of failure, and away from
Setting time from II sections is usually 0.3~0.5s, thus can not compare at the end of delay fault point high frequency voltage with
The size of operating voltage.To solve the above problems, in failure, it is necessary to judge fault point whether within II sections of protection scopes,
Then differentiate whether failure still has after 0.3~0.5s by increasing assistant criteria.If failure still has, distance II
Section will act excision failure.
Assistant criteria can use non-faulty current composition.If because failure is already cut off before delay terminates,
So new energy will no longer export fault current, therefore amplitude criterion are as follows:
imax> iop (15)
Wherein imaxFor in a time window, the maximum value of sample rate current；iopFor electric current threshold value, it can be taken as 5%~
10% rated current peak value.
Figure 12 illustrates inverse type power supply under different control strategies, and K2 point occurs BC line to line fault and when AG failure
High-frequency resistance angle.Wherein: (a) partially corresponding to and inhibit negative phase-sequence, BC；(b) partially correspond to and inhibit negative phase-sequence, AG；(c) part is corresponding
In idle, the BC of inhibition；(d) partially correspond to and inhibit idle, AG；(e) partially correspond to and inhibit active, BC；(f) partially correspond to
Inhibit active, AG.It can be calculated according to the actual parameter of inverse type power supply LCL filter for the frequency-selecting of alternate radio circuit institute
Rate should be greater than 759Hz, should be greater than 1073Hz for single-phase earthing radio circuit institute selected frequency.From (a) of Figure 12, (b) and
(c) as can be seen that measured impedance phase angle is close to -90 °, together for phase-to phase fault in the frequency range of 750Hz or more in part
When can be seen that the influence of the substantially uncontrolled strategy in high-frequency resistance angle.From Figure 12 (c), (d) and (e) part as can be seen that pair
In single-phase -90 ° close and unrelated with control strategy at the phase angle that the frequency range of 1050Hz or more measures to earth-return.It chooses altogether
There are frequency range, i.e. frequency range of the frequency of 1050Hz or more as research.
Figure 13 illustrates double-fed blower and BC (" part (a) " in figure) and AG (" part (b) " in figure) occurs in K2 point
High-frequency resistance angle when failure.According to the actual parameter of simulation model, to make its protection, equivalent high-frequency resistance corner connection is close behind
90 °, the frequency of selection should be in 1010Hz or more.As can be seen from Figure 13, in selected band limits, no matter phase fault also
It is single-line to ground fault, measuring high-frequency phase angle is in perception, close to -90 °.This is because in high band main transformer height
Frequency induction reactance value is far longer than the equivalent capacitive reactance of double-fed blower, whole still to show perceptual state.
Figure 14 shows the high frequency equivalent impedance calculated using the fault point high frequency voltage of construction.Wherein: (a) part is right
It should be in inverse type power supply, BC；(b) partially correspond to inverse type power supply, AG；(c) partially correspond to double-fed blower, BC；(d) part
Corresponding to double-fed blower, AG.It is seen from figure 14 that either inverse type power supply or double-fed blower, in addition to 1000Hz with
Under relatively low-frequency range interfered by harmonic wave other than slight fluctuation, concern 1000Hz with the simulation value of super band impedance value
It extremely coincide with theoretical value, this demonstrate that the virtual faults point high frequency voltage and true fault point high frequency voltage of construction are substantially etc.
Effect.
On this basis, be distance protection I sections of action performance of verifying, will fault point be located at K2 point, simulation result
As shown in figure 15.Wherein: (a) partially corresponding to inverse type power supply, BC；(b) partially correspond to inverse type power supply, AG；(c) part
Corresponding to double-fed blower, BC；(d) partially correspond to double-fed blower, AG.It can be seen from fig. 15 that occurring sending out route midpoint
Metallic short circuit failure, either phase-to phase fault or singlephase earth fault, virtual faults voltage be below I section of operating voltage and
II section of operating voltage, thus vhf range protection can Judging fault point in I segment limit, I section of vhf range can reliably move
Make.
It is simultaneously the action performance for verifying II section, simulated conditions are that K3 point breaks down, and simulation result is as shown in figure 16.Its
In: (a) partially correspond to inverse type power supply, BC；(b) partially correspond to inverse type power supply, AG；(c) partially correspond to double-fed wind
Machine, BC；(d) partially correspond to double-fed blower, AG.As can be seen from Figure 16, line end generation metallic short circuit event is being sent out
Barrier, either phase-to phase fault or singlephase earth fault, virtual faults voltage are above I sections of operating voltages and work lower than II section
Voltage, thus vhf range protection can Judging fault o'clock in II segment limit, vhf range protect II section of action message.
By verifying transition resistance for I section of raising frequency distance protection influence, fault point is located at K2 point, for BC phase
Between failure, fault resstance is set as 80 Ω, and for A phase ground fault, fault resstance is set as 100 Ω, simulation result such as Figure 17 institute
Show.Wherein: (a) partially corresponding to inverse type power supply, BC；(b) partially correspond to inverse type power supply, AG；(c) partially correspond to double
Present blower, BC；(d) partially correspond to double-fed blower, AG.It can be seen that from (a) and (b) two parts for inverse type power supply, when
When BC phase-to phase fault occurs for point in the line, I section is protected the resistance for being resistant to 80 Ω, occurs that 100 can be resistant to when AG failure
The resistance of Ω；It can be seen that from (c) and (d) two parts for double-fed blower, in 1000Hz~1500Hz frequency range, either BC
There is misaction in phase-to phase fault or AG failure, the I section of high frequency Sudden Changing Rate distance protection, but with the increase of frequency,
The increase of impedance circle improves the anti-of high frequency Sudden Changing Rate distance protection and crosses resistance ability, thus I sections of 1500Hz or more distance again
It can be operating normally.
Meanwhile being verifying transition resistance for II section of vhf range of influence, fault point is located at K3 point, simulation result
As shown in figure 18.Wherein: (a) partially corresponding to inverse type power supply, BC；(b) partially correspond to inverse type power supply, AG；(c) part
Corresponding to double-fed blower, BC；(d) partially correspond to double-fed blower, AG.It can be seen that from (a) and (b) two parts for inversion
Type power supply, when BC phase-to phase fault occurs, II section of distance, which is protected, can also be resistant to the resistance of 80 Ω, can also be resistance to when occurring AG failure
By the resistance of 100 Ω；It can be seen that from (c) and (d) two parts for double-fed blower, when BC phase-to phase fault occurs for K3 point,
II section is protected the tripping occurred within the scope of 1000~3000Hz, but with the increase of frequency, fault point voltage is gradually connect
Close II section of operating voltage；When AG failure occurs, in 1000~2000Hz, II section of relay fail, but when frequency reaches
When 2500Hz or more, II section of distance protection can be acted correctly.
Through the above description of the embodiments, those skilled in the art can be understood that above-described embodiment can
The mode of necessary general hardware platform can also be added to realize by software by software realization.Based on this understanding,
The technical solution of above-described embodiment can be embodied in the form of software products, which can store non-easy at one
In the property lost storage medium (can be CD-ROM, USB flash disk, mobile hard disk etc.), including some instructions are with so that a computer is set
Standby (can be personal computer, server or the network equipment etc.) executes method described in each embodiment of the present invention.
The foregoing is only a preferred embodiment of the present invention, but scope of protection of the present invention is not limited thereto,
Within the technical scope of the present disclosure, any changes or substitutions that can be easily thought of by anyone skilled in the art,
It should be covered by the protection scope of the present invention.Therefore, protection scope of the present invention should be with the protection model of claims
Subject to enclosing.
Claims (3)
1. a kind of distance protecting method for sending out route suitable for new energy station characterized by comprising
Measure the voltage and current data in failure front and back a period of time；
According to fault type, fault point high frequency voltage is calculated using the data measured；
Route will be sent out and be divided into I section of distance and II section of distance, the high-frequency work for calculating separately I section of distance with II section of distance is electric
Pressure；If I section of distance of high-frequency work voltage is not less than fault point high frequency voltage, adjusts the distance I section and carry out distance protection；If distance
II section of high-frequency work voltage is not less than fault point high frequency voltage, then after postponing a period of time, according to comparing a time window
The maximum value of interior sample rate current and the size of electric current threshold value, to judge whether II section of distance act.
2. a kind of distance protecting method for sending out route suitable for new energy station according to claim 1, feature exist
In described according to fault type, calculating fault point high frequency voltage using the data measured includes:
Fault point high frequency voltage can not be measured directly, the fault point high frequency voltage for going construction equivalent using protection installation place voltage；
Fault point high frequency voltage be by Voltage Drop before failure point failure to 0 generate, and before failure point failure voltage and protection
Voltage is of substantially equal before the failure of installation place, is gone using the high frequency voltage that Voltage Drop before protection installation place failure is generated to 0 equivalent
The high frequency voltage of fault point；
For singlephase earth fault, each variable is the high frequency voltage and high-frequency current of failure phase, and installation is mutually protected using failure
Phase voltage drops to 0 before the failure that place measures, and then extracts to obtain using wavelet transformation；For phase fault, Vk=Vkφ1-
Vkφ2, Vw=Vwφ1-Vwφ2, Iw=Iwφ1-Iwφ2, wherein φ 1 and φ 2 is two failure phases, mutually installation place is protected to survey using failure
Line voltage before the failure obtained drops to 0 construction, VkFor fault point high frequency voltage.
3. a kind of distance protecting method for sending out route suitable for new energy station according to claim 1, feature exist
In the calculation formula of I section of, the distance and II section of distance of high-frequency work voltage are as follows:
Wherein, IwIt is the high-frequency current for protecting installation place to measure, VwIt is the high frequency voltage for protecting installation place to measure；Respectively
For the high-frequency work voltage of I section of distance, II section of distance；
For I section of setting valve of distance: For II section of setting valve of distance:Its
In,For I section of safety factor, f is institute's selected frequency；L is the full inductance for sending out route.
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