CN101488661B - Adaptive determination apparatus differentiating transformer exciting surge and failure current - Google Patents
Adaptive determination apparatus differentiating transformer exciting surge and failure current Download PDFInfo
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Abstract
The invention relates to the technology of relay protection, in particular to an adaptive judging device for distinguishing transformer excitation surge current from failure current; the defects of easily causing false action of transformer differential protection and delayed protection exist in the prior art; the invention comprises an AND gate unit; the output end of the AND gate unit is an output end of decision results; the AND gate unit has three input ends; a first input end is an input end of ratio differential signals; a second input end of the AND gate unit is connected with an output end of a reversing unit; an input end of the reversing unit is an input end of harmonic braking signals; a third input end of the AND gate unit is connected with an output end of an NAND gate unit; both input ends of the NAND gate unit are respectively connected with a harmonic increment judge module and a timely or gate harmonic braking judge module. The device avoids the generation of false action, saves unnecessary overhauling, and also guarantees the security of system.
Description
[technical field]
The present invention relates to Protection Technology, specifically then a kind of differentiating transformer exciting surge and fault current of being used for determine the device that whether trips.
[background technology]
In order to guarantee the safe operation of electric power system and power transformer, generally all be provided with protective relaying device thereon, in case find the transformer troubles inside the sample space, then fast transformer is excised to avoid serious consequence from system.Yet transformer the magnetizing inrush current phenomenon can occur in running; it is fault electric current and cause tripping operation that the high current signal of its generation often can be mistaken as; cause unnecessary loss; thereby need to pass through to collect the transformer related data with differentiation magnetizing inrush current and fault current, and the tripping operation that magnetizing inrush current may cause is braked.
The judgment means of existing differentiation magnetizing inrush current and fault current mainly contains two kinds: phase-splitting braking and or door braking.
The principle of phase-splitting braking as shown in figure 11, the ratio of percentage differential signal reaction differential current (Icd) and stalling current (Izd), when both ratios greater than percentage differential setting value (Kzd) and differential current during greater than differential threshold (Imk), percentage differential signal output logic 1, otherwise be output as 0.That is:
Icd/Izd＞Kzd
Icd＞Imk
When two formulas are set up simultaneously, percentage differential signal output 1.
The harmonic braking signal is second harmonic (I in this phase differential current
2Cd) with first-harmonic (I
1Cd) ratio, when ratio greater than harmonic ratio setting value (K
2Zd) time, output logic 1.That is:
I
2cd/I
1cd＞K
2zd
When following formula is set up, harmonic braking signal logic 1.
When trip signal is 1, then control tripping operation, otherwise then do not send trip signal.The reaction speed of this braking method is very fast, and excision in time still causes the transformer differential protection misoperation easily.After the transformer differential protection action; the staff carries out the oil gas analysis again, insulation checks; this brings a large amount of work to the staff; spend the regular hour again; prolonged the repair time; simultaneously, transformer and electrical network stand again the impact of magnetizing inrush current again, have affected the insulating properties between Security of the system and transformer coil.
Or door braking as shown in figure 12, and this mode of braking is reliable, but when Transformer Close during in internal fault, or door is braked and easily caused protecting deferred action.In addition; the application of modern power systems medium and long distance transmission facility and static passive compensation device, so that secondary harmonic component is also higher in the transient fault electric current, and it is slow to decay; employing or door braking are unfavorable for protecting quick excision fault, have affected Security of the system.
[summary of the invention]
In order to overcome the defects that exists in the prior art, the invention provides the adaptive determination apparatus of a kind of differentiating transformer exciting surge and fault current, distinguish magnetizing inrush current and fault current quickly and reliably to judge, and in time make braking, guarantee Security of the system.
For this reason, the present invention is by the following technical solutions: the adaptive determination apparatus of a kind of differentiating transformer exciting surge and fault current, it is characterized in that it comprises one and gate cell, with the output of gate cell be the court verdict output, have three inputs with gate cell, first input end is the percentage differential signal input part; Then link to each other with the output of a reverse unit with the second input of gate cell, the input of this reverse unit is the harmonic braking signal input part; Then link to each other with the output of a NAND gate unit with the 3rd input of gate cell, two inputs of this NAND gate unit connect respectively harmonic wave and increase judge module and in good time or door harmonic braking judge module group.Court verdict output output trip signal, harmonic wave increase judge module and send harmonic wave increase signal, and an in good time or door harmonic braking judge module group is sent in good time or door harmonic braking signal.When the percentage differential signal be 1 and the harmonic braking signal be 0 and harmonic wave increase signal in good time or a door harmonic braking signal then send trip signal when being 0, otherwise then do not send trip signal.Present invention includes in the technology phase-splitting braking and or two kinds of structures of door braking, only drop under normal circumstances the phase-splitting braking, occurring in the situation of badly shoving, drop in good time or the door braking, but, if find that the differential current second harmonic does not increase this moment, then cancellation or door braking form the phase-splitting braking automatically.The present invention with phase-splitting of the prior art braking and or a door braking advantage carry out combination, judge that according to percentage differential signal and harmonic wave brake signal drawing brake signal has guaranteed to occur can in time move fast under the inner various failure condition at transformer, according in good time or door harmonic braking signal and harmonic wave increase signal and only then guaranteed really to break down rather than because just can send trip signal in the situation of magnetizing inrush current impact at transformer, avoided the generation of misoperation, remove unnecessary maintenance from, guaranteed Security of the system.
As further improving and replenishing technique scheme, the present invention takes following technical measures: described harmonic wave increases judge module and has percentage differential signal input part, humorous first-harmonic ratio input and harmonic wave increase setting value input, the percentage differential signal input part links to each other with one or an input of gate cell by a reverse unit and a delay unit successively, humorous first-harmonic ratio input and harmonic wave increase the setting value input then by a comparator with or another input of gate cell link to each other or the output output harmonic wave of gate cell increase signal.When certain phase ratio differential wave was 0, then output harmonic wave increased signal 1, when certain phase ratio differential wave is 1, then carries out delay process, if the percentage differential signal became 0 output harmonic wave increase signal 1 after time-delay finished; After if time-delay finishes the percentage differential signal still be 1 with certain constantly in this phase differential current the ratio of second harmonic and first-harmonic and another constantly in this phase differential current the difference of second harmonic and the ratio of first-harmonic compare with second harmonic increase setting value, if difference during greater than setting value then output harmonic wave increase signal 1, if difference during less than or equal to setting value then output harmonic wave increase signal 0, helping prevents from shoving causes malfunction.
Described in good time or a door harmonic braking judge module group comprise or door harmonic braking signaling module, combined floodgate condition judgment module and external area error judge module, or door harmonic braking signaling module links to each other with gate cell one input with one, combined floodgate condition judgment module and external area error judge module then by one or gate cell with link to each other with another input of gate cell, with the output output of gate cell in good time or door harmonic braking signal.Or door harmonic braking signaling module sends or door harmonic braking signal, and combined floodgate condition judgment module is sent the combined floodgate conditioned signal, and the external area error judge module sends external area error excision signal.When or a door harmonic braking signal when being 0, then output is in good time or door harmonic braking signal 0; When or a door harmonic braking signal when being 1, if the combined floodgate conditioned signal is 1, then export in good time or door harmonic braking signal 1, if the combined floodgate conditioned signal be 0 and external area error excision signal be 0, then export in good time or door harmonic braking signal 0, if the combined floodgate conditioned signal be 0 and external area error excision signal be 1, then output is in good time or door harmonic braking signal 1.General or door harmonic braking signal and combined floodgate conditioned signal, external area error excision signal make up, kept or the good advantage of door harmonic braking signal reliability, and further improved the reliability of judged result by combined floodgate conditioned signal, external area error excision signal.Guarantee to only have under normal circumstances the phase-splitting braking, can not cause protection deferred action in the troubles inside the sample space situation.Can drop into again or the door braking during situation various badly shoving occurring.
A described or door harmonic braking signaling module comprises one or gate cell, should or gate cell have three inputs, be respectively three phase harmonic brake signal input, or the output of gate cell output or door harmonic braking signal.
Described combined floodgate condition judgment module has the no signal current input, two transmission lines of this no signal current input by parallel connection have connected respectively or two inputs of gate cell, one of them transmission line is provided with delay unit, or the output of gate cell output combined floodgate conditioned signal.When each side no signal current, then export combined floodgate conditioned signal 1; When electric current appears in any side, then this current signal is carried out delay process, if still have current signal when time-delay finishes, then export combined floodgate conditioned signal 0, if no signal current when time-delay finishes is then exported combined floodgate conditioned signal 1, only have when each side of transformer has electric current, just to cause tripping operation.
Described external area error judge module has three-phase over-current signal and rate of three phase flow differential wave input, the percentage differential signal of every phase links to each other with an input of gate cell with one by a reverse unit, over-current signal then with another input of gate cell links to each other, be provided with delay unit between the external area error excision signal of exporting behind the output of three-phase and gate cell by being in series two or the gate cell, these two or gate cell.When certain has a side over-current signal and this phase ratio differential wave to occur to be 0 mutually, then export the outer fault-signal 1 of this phase region, otherwise then export the outer fault-signal 0 of this phase region, when fault-signal is all 0 outside the threephase region, then fault-signal is carried out delay process, if still fault-free signal, then failure removal signal 0 outside the output area when time-delay finishes, if time-delay has fault-signal, then failure removal signal 1 outside the output area when finishing; When fault-signal outside the threephase region was not all 0, then failure removal signal 1 outside the output area just sent the excision signal when only having transformer really to break down.
Beneficial effect: the present invention passes through " phase-splitting braking " and " or door braking " the effective combination of advantage; when judging that condition is shoved in existence; at first use or the door braking scheme; after the generation a period of time of shoving; again according to second harmonic increase situation select the phase-splitting braking and or the door braking; after adopting this scheme; in the time can't distinguishing the harmonic attenuation situation, drop into first in good time or the door braking; can avoid fully protecting in the situation of shoving greatly and malfunction occur; do not having the condition of shoving greatly or distinguish that harmonic wave does not increase; not in the situation of shoving; input phase-splitting braking; like this can the responsiveness of acceleration protection when closing a floodgate in internal fault; both avoid the generation of misoperation, removed unnecessary maintenance from, guaranteed again Security of the system.
[description of drawings]
Fig. 1 is workflow diagram of the present invention.
Fig. 2 is the close a floodgate generation logical flow chart of conditioned signal of the present invention.
Fig. 3 is the generation logical flow chart of external area error excision signal of the present invention.
Fig. 4 be the present invention in good time or the generation logical flow chart of door harmonic braking signal.
Fig. 5 is the generation logical flow chart that harmonic wave of the present invention increases signal.
Fig. 6 is the close a floodgate schematic diagram of condition judgment module of the present invention.
Fig. 7 is the schematic diagram of external area error judge module of the present invention.
Fig. 8 be the present invention in good time or the schematic diagram of door harmonic braking judge module group.
Fig. 9 is the schematic diagram that harmonic wave of the present invention increases judge module.
Figure 10 is structure principle chart of the present invention.
Figure 11 is existing phase-splitting braking principle schematic diagram.
Figure 12 is existing or door braking principle schematic diagram.
[embodiment]
Differentiating transformer exciting surge as shown in figure 10 and the adaptive determination apparatus of fault current, with the output of gate cell be the court verdict output, have three inputs with gate cell, first input end is the percentage differential signal input part; Then link to each other with the output of a reverse unit with the second input of gate cell, the input of this reverse unit is the harmonic braking signal input part; Then link to each other with the output of a NAND gate unit with the 3rd input of gate cell, two inputs of this NAND gate unit connect respectively harmonic wave and increase judge module and in good time or door harmonic braking judge module group.Its workflow as shown in Figure 1, calculate each side electric current, percentage differential calculating, harmonic braking calculating, combined floodgate condition judgment, external area error judgement, in good time or the judgement of door harmonic braking and harmonic wave increase judgement through over-sampling successively, then percentage differential, harmonic braking signal, harmonic wave increase signal and in good time or the door harmonic braking signal according to each phase obtains each final judged result mutually, determines whether tripping operation.
Wherein close a floodgate the production process of conditioned signal and judge module shown in Fig. 2,6, time-delay generally was made as more than 1 second, when each side no current, no signal current is put logical one, when electric current appears in any side, no signal current is put logical zero immediately, and time-delay this moment is returned element and kept returning logical zero after output logic 1 and the time-delay.
The production process of external area error excision signal and judge module are shown in Fig. 3,7, when certain had a side overcurrent to occur mutually, this phase overcurrent signal put 1, was failure to actuate if this moment, this phase ratio was differential, then send the outer fault-signal of this phase region, namely the external area error signal is put logical one.Fault-signal warp or door output outside the threephase region, or the door output signal is returned the element maintenance some time (generally greater than one second) by time-delay, when external area error excises, time-delay is returned element and is not returned immediately, thereby after guaranteeing the external area error excision, district's outer excision fault-signal can continue output logic 1, and keeps the some time (generally greater than one second).
In good time or the production process of door harmonic braking signal and judge module shown in Fig. 4,8, door harmonic braking signaling module can adopt the door harmonic braking signal generator in original or the door braking to divide.When no-load transformer drops into or drops into or the door braking during excision of secondary side's external area error because only have the middle secondary harmonic component that shoves under the both of these case less, with echo surge current in, secondary harmonic component is higher, can drop into fully or the door braking.Therefore, introducing combined floodgate conditioned signal and external area error excision signal are thrown and are moved back or the door braking, form in good time or the door brake signal.
The production process of harmonic wave increase signal and judge module are shown in Fig. 5,9, ka (t) expression t is the ratio of second harmonic and first-harmonic in the A phase differential current constantly, ka (t-Δ t) expression t subtracts the constantly ratio of second harmonic and first-harmonic in the A phase differential current of Δ t, and kzd is that second harmonic increases setting value.When ka (t-Δ t)-ka (t)＞kzd, think that secondary harmonic component increases in the A phase differential current, A phase harmonic wave increases signal and is set to 1.For preventing protecting misoperation in the algorithm transient process, shoving or the fault early period of origination, return link by time-delay and guarantee that harmonic wave increases signal and puts logical one, think that namely this time-harmonic wave increases.Because be in fault transient process and the algorithm transient process this moment, can't distinguish whether harmonic wave increases and decreases, harmonic wave is increased signal put 1 and help to drop into or the door braking, preventing from shoving causes malfunction.Delay time can be made as 100 milliseconds, after 100 milliseconds, and time delay process output logic 0, determine whether arrange harmonic wave and increase signal by differentiating second harmonic increment situation this moment.
At last, trip signal produces (Figure 10) by tripping operation control judge module, only drop under normal circumstances the phase-splitting braking, occurring in the situation of badly shoving, drop in good time or the door braking, still, if find that the differential current second harmonic does not increase this moment, then cancellation or door braking form the phase-splitting braking automatically.
Claims (1)
1. the adaptive determination apparatus of a differentiating transformer exciting surge and fault current, it is characterized in that it comprises one and gate cell, with the output of gate cell be the court verdict output, have three inputs with gate cell, first input end is the percentage differential signal input part; Then link to each other with the output of a reverse unit with the second input of gate cell, the input of this reverse unit is the harmonic braking signal input part; Then link to each other with the output of a NAND gate unit with the 3rd input of gate cell, two inputs of this NAND gate unit connect respectively harmonic wave and increase judge module and in good time or door harmonic braking judge module group; Described harmonic wave increases judge module and has percentage differential signal input part, humorous first-harmonic ratio input and harmonic wave increase setting value input, the percentage differential signal input part links to each other with one or an input of gate cell by a reverse unit and a delay unit successively, humorous first-harmonic ratio input and harmonic wave increase the setting value input then by a comparator with or another input of gate cell link to each other or the output output harmonic wave of gate cell increase signal; Described in good time or a door harmonic braking judge module group comprise or door harmonic braking signaling module, combined floodgate condition judgment module and external area error judge module, or door harmonic braking signaling module links to each other with gate cell one input with one, combined floodgate condition judgment module and external area error judge module then by one or gate cell with link to each other with another input of gate cell, with the output output of gate cell in good time or door harmonic braking signal; A described or door harmonic braking signaling module comprises one or gate cell, should or gate cell have three inputs, be respectively three phase harmonic brake signal input, or the output of gate cell output or door harmonic braking signal; Described combined floodgate condition judgment module has the no signal current input, two transmission lines of this no signal current input by parallel connection connect respectively one or two inputs of gate cell, one of them transmission line is provided with delay unit, or the output of gate cell output combined floodgate conditioned signal; Described external area error judge module has three-phase over-current signal and rate of three phase flow differential wave input, the percentage differential signal of every phase links to each other with an input of gate cell with one by a reverse unit, over-current signal then with another input of gate cell links to each other, be provided with delay unit between the failure removal signal outside the output area behind the output of three-phase and gate cell by being in series two or the gate cell, these two or gate cell.
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| CN102437551B (en) * | 2011-11-30 | 2014-09-17 | 唐山轨道客车有限责任公司 | Over-current protection device for transformer and electric locomotive |
| CN117117789B (en) * | 2023-10-24 | 2024-01-30 | 国家电网有限公司西北分部 | Transformer protection method and device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1182297A (en) * | 1997-11-06 | 1998-05-20 | 电力工业部电力自动化研究院 | Relay protection method and device to recognize symmetry of transformer exciting surge |
| CN1303156A (en) * | 2001-01-22 | 2001-07-11 | 南京南瑞继保电气有限公司 | Relay protection method based on excitation impedance variation to judge excitating surge current of transformer |
| CN201194329Y (en) * | 2008-01-17 | 2009-02-11 | 浙江省电力公司 | Adaptive determination apparatus differentiating transformer exciting surge and failure current |
-
2008
- 2008-01-18 CN CN 200810059407 patent/CN101488661B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1182297A (en) * | 1997-11-06 | 1998-05-20 | 电力工业部电力自动化研究院 | Relay protection method and device to recognize symmetry of transformer exciting surge |
| CN1303156A (en) * | 2001-01-22 | 2001-07-11 | 南京南瑞继保电气有限公司 | Relay protection method based on excitation impedance variation to judge excitating surge current of transformer |
| CN201194329Y (en) * | 2008-01-17 | 2009-02-11 | 浙江省电力公司 | Adaptive determination apparatus differentiating transformer exciting surge and failure current |
Non-Patent Citations (4)
| Title |
|---|
| JP特开2004-15861A 2004.01.15 |
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| 刘志超.三相变压器励磁涌流及保护方案.《电力系统自动化》.2006,第30卷(第10期),第58-60页. * |
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