CN104836214B - A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection - Google Patents
A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection Download PDFInfo
- Publication number
- CN104836214B CN104836214B CN201510185147.7A CN201510185147A CN104836214B CN 104836214 B CN104836214 B CN 104836214B CN 201510185147 A CN201510185147 A CN 201510185147A CN 104836214 B CN104836214 B CN 104836214B
- Authority
- CN
- China
- Prior art keywords
- protection
- switch
- transformer
- load
- fault
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000007704 transition Effects 0.000 title claims abstract description 17
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000010248 power generation Methods 0.000 title claims abstract description 9
- 238000002955 isolation Methods 0.000 claims abstract description 22
- 229910052736 halogen Inorganic materials 0.000 claims abstract description 5
- 150000002367 halogens Chemical class 0.000 claims abstract description 5
- 238000009826 distribution Methods 0.000 claims description 18
- 230000009471 action Effects 0.000 claims description 16
- 230000008859 change Effects 0.000 claims description 11
- 238000004458 analytical method Methods 0.000 claims description 8
- 230000011218 segmentation Effects 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 230000004044 response Effects 0.000 claims description 5
- 230000001131 transforming effect Effects 0.000 claims description 5
- 230000004308 accommodation Effects 0.000 claims description 3
- 230000006837 decompression Effects 0.000 claims description 3
- 230000007812 deficiency Effects 0.000 claims description 3
- 230000007613 environmental effect Effects 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 208000019901 Anxiety disease Diseases 0.000 claims description 2
- 230000036506 anxiety Effects 0.000 claims description 2
- 230000001052 transient effect Effects 0.000 abstract description 5
- 230000009977 dual effect Effects 0.000 abstract description 4
- 230000013011 mating Effects 0.000 abstract description 3
- 230000000875 corresponding effect Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 6
- 230000006378 damage Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000007257 malfunction Effects 0.000 description 2
- 238000007726 management method Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000005267 amalgamation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
Landscapes
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses one based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection when DG capacity constantly increases; its short circuit current level made increases; DG character is also converted to " small power supply " character by original " pure load ", and existing protection and switch breakpoint cannot meet the needs of transient condition.This programme is under existing protection and switch breakpoint condition; by mating with the continuous of an operational mode, continuing to optimize of scheme, the continuous interchange of information and quantity of state; form the protecting control interface adapted with primary system, reach system safety operation and the dual purpose continued of powering.The determination of Fault Isolation scope needs to collect the determined new border of switch cut-off point, and this boundary point will be considered once the system splitting determining and produce thereupon and decoupled mode whether Absorbable organic halogens runs.
Description
Technical field
The present invention relates to a kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection.
Background technology
At the distributed power source networking initial stage, because its scale has uncertainty, grid connection capacity is less, and the short circuit current provided system is limited, less on existed system protection impact, now can be regarded as " pure load " character.But when distributed power source capacity constantly increases (>5MVA), DG has just had the feeding ability providing relatively high fault current, such as, the DG that 10 ~ 35kV bus directly connects, about 6 times of rated current can be provided in the very short duration, connect DG cell failure electric current by inverter and also can reach 4 times of rated current.At this moment just can not treat with load character again, but now the corresponding protective device of system side does not follow up, and affects the stable operation of electrical network.
Therefore study how under DG transient mode, obtaining the most effective protection scheme with limited reserved resource has positive effect.Simultaneously under this transient mode, consider that fully demonstrating the continued power advantage of DG to important load is also take into account the target of consideration how when system jam.
Summary of the invention
The present invention is in order to solve the problem; propose a kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection; this method passes through the optimization of earthing mode and secondary protection system; solve DG by the complexity problem of simple " load " character to the transition of " small power supply " character; when existing protection and automatics constant; by related art method, reach the object substantially meeting the rear area power grid safe operation of DG access.
To achieve these goals, the present invention adopts following technical scheme:
A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection, comprise the following steps:
(1) the Fault Isolation border of clear and definite DG capacity, adjusts its protection definite value, determines decoupled mode lower boundary point after Fault Isolation, after DG capacity increases to set point, the transformer grounding mode of grid-connected transformer station adjusted;
(2) under existing relaying configuration condition, local low-frequency and low-voltage device is coordinated mutually with electrical power distribution automatization system, complete the transfer of accident afterload and isolated island division;
(3) according to decoupled mode, formulate relaying configuration scheme, carry out failure response analysis, the continued power between realizing one-level important load age at failure, and the protection of corresponding microgrid adjusts on the island in.
In described step (1), when local DG capacity constantly increases, when reaching the capability value of setting, DG just can not be used as simple load and consider, and should be regarded as be connected with system, with the distributed power source of generating set different in kind.
In described step (1), first want clear and definite DG capacity to cause mismatching of protection when which rising to and putting, thus need adjustment protection definite value; Next be due to DG capacity be less than 50MW protection and switchgear distribution will be incomplete when DG considers as " small power supply "; if want the effective isolated fault when fault occurs; at this moment fault cut-off point needs to carry out following adjustment: jump DG online transforming plant main transformer high-pressure side and bridge switch, grid-connected wiretap cut by connection simultaneously.
In described step (1), when DG capacity increases to set point degree, need to consider at which switch breakpoint to disconnect, form decoupled mode, meanwhile, after formation isolated island, take into account and consider for microgrid protection in island; Redistributing for the load after Fault Isolation, is equally also to take into full account load importance and under supplying the prerequisite of balancing relation with locality, load loss to be down to minimum by off-the-line and low-frequency low-voltage load shedding device.
In described step (2), under transition operational mode, due to switch cut-off point distribution and can the deficiency of stand-by power supply need corresponding protection and automatic safety device scheme to make accommodation; When carrying out scheme and determining, first the determination of Fault Isolation scope needs to collect the determined new border of switch cut-off point, and this boundary point will be considered once the system splitting determining and produce thereupon and decoupled mode whether Absorbable organic halogens runs.
In described step (2), in order to realize the reliability service of the important load after accurate isolated fault, needing considering cost and energy information, manage and environmental information, to control and metrical information, critical condition information and load user profile; When power resources anxiety; need comprehensively to analyze consideration to network topology structure, trend distribution, switch distribution, relaying configuration and the load balancing ability of local DG and the character factor of local supply load; could determine to be applicable to reliable, the economic protection under current operational mode and automatic safety device scheme; scheme determines the matching relationship of each switch and relaying configuration point, is used for realizing originally obtaining optimum load transfer plan scheme with minimum isolation range isolated fault and with minimum one-tenth.
In described step (3); because DG character there occurs change; by grid-connected high voltage side of transformer ground connection; the protection of offside system line stretches into transformer by original distance, zero sequence I section; change into and protect circuit 85%; and by means of the zero-sequenceprotection of our station high voltage side of transformer as power line main protection, jump high-pressure side and bridge switch, grid-connected wiretap cut by connection simultaneously.
In described step (3), protection act is as follows: during line fault, two ends circuit breaker tripping does not overlap, standby throwing action, and connection cuts DG and the pattern of netting twine, and now regional area will enter decoupled mode; As this side switch of low-pressure side time-limit quick break protection tripping of the nearly standby of low-pressure side and low-pressure side bus main protection, connection cuts DG and netting twine, and the segmentation of locking low-pressure side is standby throws; Main transformer differential and non-ionizing energy loss action, not locking transforming plant lead-in and the standby throwing of low-pressure side segmentation.
In described step (3), when becoming operation for one, system side line failure, by standby high voltage side of transformer switch motion of throwing Union Switch Device, the service channel of direct cut-out photovoltaic and system, high-voltage side bus decompression, the regular event of prepared auto restart can not be affected, but become for two the mode simultaneously run, high voltage side of transformer switch motion can not cut off the passage of distributed power source completely, therefore the success rate of prepared auto restart can be affected, need connection to cut the also netting twine of our station photovoltaic while high backup protection action for this reason, and becoming paired running by original two changes by after a change operation, need the low frequency of low-pressure side, low-voltage device action, equilibrium is carried out to corresponding load, to reach the problem ensureing power supply quality.
In described step (3), select, at distributed power source grid-connected transformer station high-pressure side installing bus differential protection, when bus breaks down, to export locking spare power by bus bar differential prptection operation node; If do not configure bus differential protection, determine whether busbar fault by comparing the fault current size flowing through inlet wire transformer substation side switch and high voltage side of transformer disconnecting link.
In described step (3), when the electric current that inlet wire transformer substation side switch flows through is greater than the fault current that transformer high-voltage side tool flows through, be illustrated as busbar fault; Because when only having fault point between two switches, just there will be the short circuit current that the short circuit current provided by system that inlet wire transformer substation side switch experiences is provided much larger than high voltage side of transformer disconnecting link by distributed power source.
In described step (3); under the prerequisite that DG relevant device can not be caused to damage; no matter it is differential that DG side is that frequency or voltage relay all exceed a cooperation than the protection of system side correspondence; this also just ensure that when system side breaks down, and DG can not cause realizing the effective support to system prior to the corresponding actuating of relay of system side.
Beneficial effect of the present invention is:
(1) when DG capacity constantly increases, its short circuit current level made increases, DG character is also converted to " small power supply " character by original " pure load ", existing protection and switch breakpoint cannot meet the needs of transient condition, the present invention is under existing protection and switch breakpoint condition, by mating with the continuous of an operational mode, continuing to optimize of scheme, the continuous interchange of information and quantity of state, form the protecting control interface adapted with primary system, reach system safety operation and the dual purpose continued of powering;
(2) by changing transformer grounding mode, when guaranteeing the system failure, effectively fault can be found;
(3) achieve the effective isolation to the system failure by means of high voltage side of transformer zero sequence overcurrent and switch simultaneously;
(4) coordinated by the definite value of protection and automatics, ensure that after Fault Isolation, effective transfer load; Operated by DG islet operation, maintain the continued power of DG to local load, and its protection also achieves microgrid defencive function, the situation constantly increasing access local for a large amount of DG provides effective solution.
Accompanying drawing explanation
Fig. 1 is scheme selection flowcharts of being correlated with when changing based on DG character of the present invention;
Fig. 2 is the protection and the automatic safety device solution principle schematic diagram that the present invention is based on the fusion of information height;
Fig. 3 is distributed power source of the present invention access 110kV bus arrangement figure;
Fig. 4 is for be changed by DG character and switch cut-off point determines initial protection and off-the-line scheme;
Fig. 5 is the concrete enforcement schematic diagram of protection scheme;
Fig. 6 is that failure response analyzes schematic diagram;
Fig. 7 (a) is for being applicable to the microgrid coordination relationship of protection schematic diagram of decoupled mode;
Fig. 7 (b) is for being applicable to the microgrid coordination relationship of protection schematic diagram of decoupled mode;
Fig. 7 (c) is for being applicable to the microgrid coordination relationship of protection schematic diagram of decoupled mode.
Embodiment:
Below in conjunction with accompanying drawing and embodiment, the invention will be further described.
Invention describes the advanced Fault Management System scheme in DG transition period; this scheme is based on existing relaying configuration and distribution automation system equipment (comprising equipment automatization and remote-controllable switches); protection required when it can provide DG grid-connected; reduce trouble duration simultaneously, reduce and fail the DG electric energy confessed and cause DG axle moment of torsion due to electric energy and mechanical energy imbalance.It content comprised is as follows:
1) when DG capacity increases to a certain degree, the transformer grounding mode of grid-connected transformer station is adjusted;
2) under existing relaying configuration condition, local low-frequency and low-voltage device is coordinated mutually with electrical power distribution automatization system, complete the transfer of accident afterload and isolated island division;
3) by the operation of " isolated island " operational mode, the continued power between realizing one-level important load age at failure, and the protection of corresponding microgrid adjusts on the island in.
The object of the invention is the optimization by earthing mode and secondary protection system; solve DG by the complexity problem of simple " load " character to the transition of " small power supply " character; when existing protection and automatics constant; by related art method, reach the object substantially meeting the rear area power grid safe operation of DG access.
The program, by changing the earthing mode of substation transformer, the configuration of protective device, fixed value adjusting scheme and prepared auto restart, low-frequency and low-voltage off-the-line mode, at utmost reduces trouble duration, prevents the damage of DG.1) when DG capacity increases to a certain degree, the transformer grounding mode of grid-connected transformer station is adjusted;
2) under existing relaying configuration condition, local low-frequency and low-voltage device is coordinated mutually with electrical power distribution automatization system, complete the transfer of accident afterload and isolated island division;
3) by the operation of " isolated island " operational mode, the continued power between realizing one-level important load age at failure, and the protection of corresponding microgrid adjusts on the island in.
Scheme comprises following concrete steps:
1 coordinates the proposition of integrated protection scheme policies based on the grid-connected transition operational mode of DG
The international large-scale power system committee (CIGRE) is pointed out, distributed power generation is defined as " non-through planning or the electrical production mode of central schedule type, be usually connected with power distribution network, general generating scale is between 50 ~ 100MW.Therefore, when local DG capacity constantly increases, when reaching capability value (50MVA) of setting, DG just can not be used as simple " load " and consider, and should be regarded as be connected with system, with " distributed power source " of generating set different in kind.The problem that its protection and automatics needs solve is exactly the problem of two aspects: 1. effective isolated fault; 2. the guarantee of maximum magnitude is effectively powered.In order to solve first problem, first wanting clear and definite DG capacity to cause mismatching of protection when which rising to and putting, thus needing adjustment protection definite value; Next be due to DG capacity less time protection and switchgear distribution will be incomplete when DG considers as " small power supply ", if want the effective isolated fault when fault occurs, fault cut-off point at this moment needs to adjust accordingly.In order to solve Second Problem, to the tenability of local load when namely DG capacity increases to a certain degree, therefore; need to consider at which switch breakpoint to disconnect, form decoupled mode, simultaneously; after formation isolated island, the realization for microgrid protection in island also needs to take into account consideration.As a same reason, redistributing for the load after Fault Isolation, is equally also to take into full account load importance and under supplying the prerequisite of balancing relation with locality, load loss to be down to minimum by off-the-line and low-frequency low-voltage load shedding device.Fig. 1 gives the logical flow chart of this Developing Tactics.As can be seen from the figure, protection scheme will consider two problems simultaneously, and one is how DG determines Fault Isolation border when continuing to provide short circuit current to fault point as " small power supply ", and two is the determinations of decoupled mode lower boundary point after Fault Isolation.Therefore, cut-off point not only will serve as the function of Fault Isolation breakpoint, is also the boundary point dynamically dividing decoupled mode simultaneously; As a same reason, DG also has " dual role ", and one is provide short circuit current to need fully to isolate when breaking down as " small power supply ", and two is the roles that also will serve as local power supply after breakdown judge, maintains decoupled mode.
Under transition operational mode, due to switch cut-off point distribution and can the deficiency of stand-by power supply need corresponding protection and automatic safety device scheme to make accommodation.When carrying out scheme and determining, first the determination of Fault Isolation scope needs to collect the determined new border of switch cut-off point, and this boundary point will be considered once the system splitting determining and produce thereupon and decoupled mode whether Absorbable organic halogens runs.Therefore, in order to realize the reliability service of the important load after accurate isolated fault, need to consider multiple factor, therefore information flow will relate to following 5 aspects alternately:
Cost and energy information
Management and environmental information
Control and metrical information
Critical condition information
Load user profile
When power resources is relatively nervous, need network topology structure, trend distributes, switch distributes, the load balancing ability of relaying configuration and local DG, the factors such as the character of local supply load comprehensively analyze consideration, and suitably consider the parameter error that some variablees may bring, that could determine to be applicable under current operational mode is reliable, economic protection and automatic safety device scheme, scheme determines the matching relationship of each switch and relaying configuration point, be used for realizing originally obtaining optimum load transfer plan scheme with minimum isolation range isolated fault and with minimum one-tenth.Information flow direction and amalgamation mode are as shown in Figure 2.According to load importance rate and local load balancing ability determination load transfer plan scheme.As shown in Figure 2, scheme proposition and to solve be in fact based on the analyzing and processing of 5 kinds of heterogeneity information sources and comprehensive.In brief, namely as the formation of the protection scheme of the first level, mainly based on the result of switch (fault cut-off point) and Failure Mode Analysis; And in order to can successful transfer load after accident, system splitting mode not only to consider existing switch disconnect after formation and isolated island dividing mode, also to consider the problem of several aspects such as tidal current analysis, economic analysis, load character.Therefore, in whole Data Source, first to extract needed for Resolving probiems for information about, then according to existing rule and weight design, finally form power network safety operation, efficient scheme that user's reliable and economic is run.
3 based on DG character and the protection scheme enforcement of closing breakpoint
3.1 protect and off-the-line scheme at first based on the protection of the once side of fortune and switch
Because DG character there occurs change in this programme; by grid-connected high voltage side of transformer ground connection; the protection of offside system line stretches into transformer by original distance, zero sequence I section; change into and protect circuit 85%; and by means of the zero-sequenceprotection of our station high voltage side of transformer as power line main protection; jump high-pressure side and bridge switch, grid-connected wiretap cut by connection simultaneously.The switch cut-off point that its new operational mode determines and non-fully relaying configuration are as shown in Figure 4.
The 3.2 switch breakpoints determined by transition operational mode and insufficient relaying configuration scheme
Fig. 3 distributed power source access 110kV bus arrangement figure.What wherein MV/LV transformer station adopted is internal cavity quality, and wherein 01,02 is disconnecting link, and the connection that wherein trips is cut and netting twine L1 function, is to be joined by 03 switch trip to cut functional realiey.Due to the reason of its initial designs small scale; the grid-connected transformer station of its distribution power is considered as the end stations without small power incorporating into power network, therefore, at transformer substation side switch (03; 04) therefore not configuration protection device is first-selected by means of the backup protection of #1, #2 transformer height.As long as generally meet protection sensitivity requirement; the standby of transformer height can't be protected by efficiency configure; consider that photo-voltaic power supply provides short circuit current ability when the system failure simultaneously; up to the present there is not the algorithm that can be applied to engineering reality simultaneously, therefore need the source of trouble of the reliable accurate response system failure of searching one.Comprehensive above two factors, the most direct solution is considered as " small power supply " by distributed power source, by the 110kV side joint of transformer station ground.Zero-sequencedirectional protection in high backup protection is considered as load side 03, the route protection of 04, its setting principle is also follow this side line road relaying configuration principle simultaneously; I section hide this line line end fault; II section breaks even line total length and ensure sensitivity, and matches with all outlets of offside transformer station (220kV stands).Like this when system jam, provide enough zero-sequence fault electric currents by high voltage side of transformer earth point to fault point, its transformer height backup protection action made, switch 03 (or 04) tripping.From analysis, the determination of transformer grounding point is that distributed power source is grid-connected from which platform transformer, and this high voltage side of transformer runs with regard to ground connection.Ground connection is run just in order to provide a zero-sequence current source to the system failure, and this zero sequence system and distributed power source have nothing to do.However, because distributed power source is grid-connected at this main transformer, after the tripping of this change high side switch, with regard to effective, distributed power source is isolated from electrical network.
3.3 failure response analyses
According to current relaying configuration, protection act is as follows: during line fault, two ends circuit breaker tripping does not overlap, standby throwing action, and connection cuts DG and the pattern of netting twine, and now regional area will enter decoupled mode; As this side switch of low-pressure side time-limit quick break protection tripping of the nearly standby of low-pressure side and low-pressure side bus main protection, connection cuts DG and netting twine, and the segmentation of locking low-pressure side is standby throws; Main transformer differential and non-ionizing energy loss action, not locking transforming plant lead-in and the standby throwing of low-pressure side segmentation.
When becoming operation for one, system side line failure, will by 03 switch motion, and directly cut off the service channel of photovoltaic and system, high-voltage side bus decompression, can not affect the regular event of prepared auto restart.But become for two the mode simultaneously run; high voltage side of transformer switch 03 action can not cut off the passage of distributed power source completely; therefore the success rate of prepared auto restart can be affected; need connection to cut the also netting twine L1 of our station photovoltaic while high backup protection action, according to current relaying configuration, this can meet for this reason.And become paired running by original two to change by after a change operation, need the low frequency of low-pressure side, low-voltage device action, equilibrium is carried out to corresponding load, to reach the problem ensureing power supply quality.And the load of tripping can solving hand in hand by means of distribution after balance.
Can be found out by the protection range of high standby zero-sequenceprotection, the expanded range of 03 switch protection is to high-voltage side bus.From analysis, when high-voltage side bus breaks down, identify and locking measure if not effective, standby throwing will be caused again to throw in fault, cause the Secondary Shocks again to system.Best solution is selected at distributed power source grid-connected transformer station high-pressure side installing bus differential protection, when bus breaks down, exports locking spare power by bus bar differential prptection operation node; If do not configure bus differential protection, busbar fault can be determined whether by comparing the fault current size flowing through 03 and 01 switch.As I03 > I01, be illustrated as busbar fault.Because when only having fault point between two switches, just there will be the short circuit current that the short circuit current provided by system that 03 switch experiences is provided much larger than 01 switch by distributed power source.Note, zero-sequence current is no longer basis for estimation here, but directly compares the short circuit current size that both sides power supply provides.
4 based on DG character and the load transfer plan and the islanding operation scheme implementation that close breakpoint
As shown in Figure 3, step down side DG netting twine and form a whole set of protection cooperation system to each DG generator unit.Can find out with and netting twine for separation; the short circuit current that system side should provide with system side is benchmark of adjusting; and should take PD2 as initial point as the protection system under decoupled mode after grid-connected switch tripping; therefore for ensureing that it can be applicable to microgrid operation mode, little many short circuit currents that this system should provide with DG are for benchmark.The result of such process; although can make to provide the protection meeting of short circuit current level relative system side very sensitive based on DG; also its action can be caused to enter decoupled mode at system jam; but can be addressed this problem by time coordination, but the selectivity that its protection is simultaneously protected under also can being applicable to grid-connected and " isolated island " simultaneously.
When considering the system failure, DG needs effectively to support local load as power supply; we do not wish that it is when the system failure; in failure removal process and when system loading balance does not complete, DG stops transport; therefore, the corresponding matching relation of relevant to power supply quality voltage, frequency protection and low frequency, low-voltage load sheding equipment and system side is as shown in Fig. 7 (a), (b), (c).
Known from the matching relationship Fig. 7 (a), (b), (c); under the prerequisite that DG relevant device can not be caused to damage; no matter it is differential that DG side is that frequency or voltage relay all exceed a cooperation than the protection of system side correspondence; this also just ensure that when system side breaks down, and DG can not cause realizing the effective support to system prior to the corresponding actuating of relay of system side., also can find out, based on the consideration of DG decoupled mode, the definite value of its DG side protection is with DG rated capacity for benchmark, i.e. PD meanwhile
3a=2.5I
n-DG; And system side protection what get is for benchmark PD with this side rated current
3a=2.5I
n-LV.Although DG side definite value value is relatively much lower, due to the time differential on cooperation, after the system side made breaks down, its protection can not malfunction, meanwhile, still can keep its defencive function when DG enters decoupled mode, eliminates the fault of generation in island in time.
Describe a kind of based on DG grid-connected transition operational mode coordination integrated protection scheme policies herein; when DG capacity constantly increases; its short circuit current level made increases; DG character is also converted to " small power supply " character by original " pure load ", and existing protection and switch breakpoint cannot meet the needs of transient condition.This programme is under existing protection and switch breakpoint condition; by mating with the continuous of an operational mode, continuing to optimize of scheme, the continuous interchange of information and quantity of state; form the protecting control interface adapted with primary system, reach system safety operation and the dual purpose continued of powering.First the determination of Fault Isolation scope needs to collect the determined new border of switch cut-off point, and this boundary point will be considered once the system splitting determining and produce thereupon and decoupled mode whether Absorbable organic halogens runs.By changing transformer grounding mode, when guaranteeing the system failure, effectively fault can be found; Achieve the effective isolation to the system failure by means of high voltage side of transformer zero sequence overcurrent and switch simultaneously; Coordinated by the definite value of protection and automatics, ensure that after Fault Isolation, effective transfer load; Operated by DG islet operation, maintain the continued power of DG to local load, and its protection also achieves microgrid defencive function.The situation that this scheme constantly increases access local for a large amount of DG provides effective solution.
Embodiment one: as shown in Figure 3, step down side DG netting twine and form a whole set of protection cooperation system to each DG generator unit.Can find out with and netting twine for separation; the short circuit current that system side should provide with system side is benchmark of adjusting; and should take PD2 as initial point as the protection system under decoupled mode after grid-connected switch tripping; therefore for ensureing that it can be applicable to microgrid operation mode, little many short circuit currents that this system should provide with DG are for benchmark.The result of such process; although can make to provide the protection meeting of short circuit current level relative system side very sensitive based on DG; also its action can be caused to enter decoupled mode at system jam; but can be addressed this problem by time coordination, but the selectivity that its protection is simultaneously protected under also can being applicable to grid-connected and " isolated island " simultaneously.
When considering the system failure, DG needs effectively to support local load as power supply; we do not wish that it is when the system failure; in failure removal process and when system loading balance does not complete, DG stops transport; therefore, the corresponding matching relation of relevant to power supply quality voltage, frequency protection and low frequency, low-voltage load sheding equipment and system side is as shown in Fig. 7 (a), Fig. 7 (b), Fig. 7 (c).
Known from the matching relationship Fig. 7 (a), Fig. 7 (b), Fig. 7 (c); under the prerequisite that DG relevant device can not be caused to damage; no matter it is differential that DG side is that frequency or voltage relay all exceed a cooperation than the protection of system side correspondence; this also just ensure that when system side breaks down, and DG can not cause realizing the effective support to system prior to the corresponding actuating of relay of system side., also can find out, based on the consideration of DG decoupled mode, the definite value of its DG side protection is with DG rated capacity for benchmark, i.e. PD meanwhile
3a=2.5I
n-DG; And system side protection what get is for benchmark PD with this side rated current
3a=2.5I
n-LV.Although DG side definite value value is relatively much lower, due to the time differential on cooperation, after the system side made breaks down, its protection can not malfunction, meanwhile, still can keep its defencive function when DG enters decoupled mode, eliminates the fault of generation in island in time.
By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.
Claims (2)
1. coordinate a comprehensive method of protection based on the grid-connected transition operational mode of distributed power generation, it is characterized in that: comprise the following steps:
(1) the Fault Isolation border of clear and definite DG capacity, adjusts its protection definite value, determines decoupled mode lower boundary point after Fault Isolation, after DG capacity increases to set point, the transformer grounding mode of grid-connected transformer station adjusted;
(2) under existing relaying configuration condition, local low-frequency and low-voltage device is coordinated mutually with electrical power distribution automatization system, complete the transfer of accident afterload and isolated island division;
(3) according to decoupled mode, formulate relaying configuration scheme, carry out failure response analysis, the continued power between realizing one-level important load age at failure, and the protection of corresponding microgrid adjusts on the island in;
In described step (1), first want clear and definite DG capacity to cause mismatching of protection when which rising to and putting, thus need adjustment protection definite value; Next is less than 50MW protection and switchgear distribution carries out following adjustment at fault cut-off point when DG capacity: jump DG and to surf the Net transforming plant main transformer high-pressure side and bridge switch, grid-connected wiretap cut by connection simultaneously;
In described step (1), when DG capacity increases to set point degree, need to consider at which switch breakpoint to disconnect, form decoupled mode, meanwhile, after formation isolated island, take into account and consider for microgrid protection in island; Redistributing for the load after Fault Isolation, is equally also to take into full account load importance and under supplying the prerequisite of balancing relation with locality, load loss to be down to minimum by off-the-line and low-frequency low-voltage load shedding device;
In described step (2), under transition operational mode, due to switch cut-off point distribution and can the deficiency of stand-by power supply need corresponding protection and automatic safety device scheme to make accommodation; When carrying out scheme and determining, first the determination of Fault Isolation scope needs to collect the determined new border of switch cut-off point, and this boundary point will be considered once the system splitting determining and produce thereupon and decoupled mode whether Absorbable organic halogens runs;
In described step (2), in order to realize the reliability service of the important load after accurate isolated fault, needing considering cost and energy information, manage and environmental information, to control and metrical information, critical condition information and load user profile; When power resources anxiety, need comprehensively to analyze consideration to network topology structure, trend distribution, switch distribution, relaying configuration and the load balancing ability of local DG and the character factor of local supply load, could determine to be applicable to reliable, the economic protection under current operational mode and automatic safety device scheme, scheme determines the matching relationship of each switch and relaying configuration point, is used for realizing originally obtaining optimum load transfer plan scheme with minimum isolation range isolated fault and with minimum one-tenth;
In described step (3), because DG character there occurs change, by grid-connected high voltage side of transformer ground connection, the protection of offside system line stretches into transformer by original distance, zero sequence I section, change into and protect circuit 85%, and by means of the zero-sequenceprotection of our station high voltage side of transformer as power line main protection, jump high-pressure side and bridge switch, grid-connected wiretap cut by connection simultaneously;
In described step (3), protection act is as follows: during line fault, two ends circuit breaker tripping does not overlap, standby throwing action, and connection cuts DG and the pattern of netting twine, and now regional area will enter decoupled mode; As this side switch of low-pressure side time-limit quick break protection tripping of the nearly standby of low-pressure side and low-pressure side bus main protection, connection cuts DG and netting twine, and the segmentation of locking low-pressure side is standby throws; Main transformer differential and non-ionizing energy loss action, not locking transforming plant lead-in and the standby throwing of low-pressure side segmentation;
In described step (3), when becoming operation for one, system side line failure, by standby high voltage side of transformer switch motion of throwing Union Switch Device, the service channel of direct cut-out photovoltaic and system, high-voltage side bus decompression, the regular event of prepared auto restart can not be affected, but become for two the mode simultaneously run, high voltage side of transformer switch motion can not cut off the passage of distributed power source completely, therefore the success rate of prepared auto restart can be affected, need connection to cut the also netting twine of our station photovoltaic while high backup protection action for this reason, and becoming paired running by original two changes by after a change operation, need the low frequency of low-pressure side, low-voltage device action, equilibrium is carried out to corresponding load, to reach the problem ensureing power supply quality,
In described step (3), select, at distributed power source grid-connected transformer station high-pressure side installing bus differential protection, when bus breaks down, to export locking spare power by bus bar differential prptection operation node; If do not configure bus differential protection; busbar fault is determined whether by comparing the fault current size flowing through inlet wire transformer substation side switch and high voltage side of transformer disconnecting link; when the electric current that inlet wire transformer substation side switch flows through is greater than the fault current that transformer high-voltage side tool flows through, be illustrated as busbar fault.
2. as claimed in claim 1 a kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection; it is characterized in that: in described step (1); when local DG capacity constantly increases; when reaching the capability value of setting; DG is not just used as simple load and considers, and should be regarded as be connected with system, with the distributed power source of generating set different in kind.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510185147.7A CN104836214B (en) | 2015-04-17 | 2015-04-17 | A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510185147.7A CN104836214B (en) | 2015-04-17 | 2015-04-17 | A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104836214A CN104836214A (en) | 2015-08-12 |
| CN104836214B true CN104836214B (en) | 2016-02-17 |
Family
ID=53813914
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510185147.7A Active CN104836214B (en) | 2015-04-17 | 2015-04-17 | A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104836214B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105186468B (en) * | 2015-08-13 | 2018-01-16 | 广东电网有限责任公司佛山供电局 | A kind of power distribution network directional over-current protection on-line tuning method and system of distributed power source access |
| CN105117797B (en) * | 2015-08-13 | 2019-01-08 | 浙江工业大学 | The microgrid economic optimum dispatching method a few days ago divided based on isolated island |
| CN105207178B (en) * | 2015-09-11 | 2016-06-29 | 国家电网公司 | A kind of based on the DG Distribution Network Failure accessed location and isolated island division methods |
| CN105162086B (en) * | 2015-09-11 | 2016-06-29 | 国家电网公司 | Guard method for the grid-connected transformer grounding system of DG |
| CN106099973A (en) * | 2016-06-29 | 2016-11-09 | 华能重庆两江燃机发电有限责任公司 | A kind of Rhizoma Sparganii M701F4 type 3 simultaneous interconnecting implementation methods of unit gas turbine transformer unit |
| CN106099875A (en) * | 2016-07-07 | 2016-11-09 | 周丽玲 | A kind of based on distributed power generation grid-connected transition method of operation coordination comprehensive method of protection |
| CN106410766B (en) * | 2016-11-11 | 2017-10-13 | 国网山东省电力公司枣庄供电公司 | Based on the high containment guard method of DG interconnected electric power systems |
| CN110601154B (en) * | 2019-08-26 | 2021-10-01 | 南京南瑞继保电气有限公司 | Relay protection configuration method for alternating current system with power electronic power generation equipment |
| CN111130218B (en) * | 2019-12-25 | 2022-05-10 | 深圳供电局有限公司 | Transformer substation security bus difference unification device |
| CN112134311B (en) * | 2020-09-15 | 2022-06-14 | 广东电网有限责任公司韶关供电局 | Control method, device, equipment and storage medium for small hydropower station power grid |
| CN112165090A (en) * | 2020-09-29 | 2021-01-01 | 国电南瑞南京控制系统有限公司 | Cooperative self-healing system and method |
| CN112510658B (en) * | 2020-11-11 | 2022-11-22 | 广西电网有限责任公司电力科学研究院 | Multi-power-point 10kV line feeder automation method with high power supply reliability |
| CN115498699B (en) * | 2022-11-21 | 2023-01-20 | 广东电网有限责任公司中山供电局 | Energy storage converter grid-connected and off-grid switching method, system, equipment and medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102882197A (en) * | 2012-10-30 | 2013-01-16 | 山东电力集团公司烟台供电公司 | DG (distributed generation)-containing power distribution network distributed protection and control method |
| CN103036219A (en) * | 2012-12-10 | 2013-04-10 | 华北水利水电学院 | Low-voltage micro-grid comprehensive protection method |
| CN103944160A (en) * | 2014-04-09 | 2014-07-23 | 国家电网公司 | Distribution network protection and automatic device cooperating method based on DG characteristics |
-
2015
- 2015-04-17 CN CN201510185147.7A patent/CN104836214B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102882197A (en) * | 2012-10-30 | 2013-01-16 | 山东电力集团公司烟台供电公司 | DG (distributed generation)-containing power distribution network distributed protection and control method |
| CN103036219A (en) * | 2012-12-10 | 2013-04-10 | 华北水利水电学院 | Low-voltage micro-grid comprehensive protection method |
| CN103944160A (en) * | 2014-04-09 | 2014-07-23 | 国家电网公司 | Distribution network protection and automatic device cooperating method based on DG characteristics |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104836214A (en) | 2015-08-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104836214B (en) | A kind of based on distributed power generation grid-connected transition operational mode coordination comprehensive method of protection | |
| Memon et al. | A critical review of AC Microgrid protection issues and available solutions | |
| Javadian et al. | Adaptive centralized protection scheme for distribution systems with DG using risk analysis for protective devices placement | |
| Meneses et al. | Improving the grid operation and reliability cost of distribution systems with dispersed generation | |
| Nassif | An analytical assessment of feeder overcurrent protection with large penetration of distributed energy resources | |
| Sati et al. | Optimal protection coordination for inverter dominated islanded microgrids considering N-1 contingency | |
| CN105119251A (en) | Method suitable for determining grounding resistance scheme of flexible direct-current power distribution system | |
| Zarei et al. | Protection of active distribution networks with conventional and inverter-based distributed generators | |
| CN107612021B (en) | Regional spare power automatic switching control method suitable for large number of small power supplies to access local power grid | |
| So et al. | Protection relay coordination on ring-fed distribution network with distributed generations | |
| Sanaye-Pasand | Scrutiny of the Iranian national grid | |
| Yousaf et al. | Risk of loss of protection coordination in distribution grids with high penetration of distributed energy resources | |
| Emhemed et al. | Protection analysis for plant rating and power quality issues in LVDC distribution power systems | |
| Yousaf et al. | Assessment of protective device sensitivity with increasing penetration of distributed energy resources | |
| Abdel‐Ghany et al. | Defining the practical constraints of inserting DG units in distribution systems regarding protection schemes | |
| Kim et al. | Active TCC based protection coordination scheme for networked distribution system | |
| Yang et al. | Optimal protection coordination for microgrid under different operating modes | |
| Bari et al. | Smart and adaptive protection scheme for distribution network with distributed generation: A scoping review | |
| CN108054738B (en) | Power distribution protection method and device for power grid | |
| CN106772018B (en) | The method of discrimination of one Ge Ban main electrical scheme substation's dead-zone fault choosing string | |
| Sridhar | Case study of grid connected PV plant feeding power to electrical submersible pumps | |
| Conti et al. | Analysis of protection issues in autonomous MV micro-grids | |
| Taleb et al. | Maintaining fuse in the presence of distributed generation sources in the distribution network to improve protection system | |
| Pereira et al. | Control and protection of active distribution systems using a new multiobjective mathematical model | |
| Farmad et al. | Power quality customer financial impact/risk assessment tool |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| EXSB | Decision made by sipo to initiate substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |