CN100438248C - Protective relay - Google Patents
Protective relay Download PDFInfo
- Publication number
- CN100438248C CN100438248C CNB028277708A CN02827770A CN100438248C CN 100438248 C CN100438248 C CN 100438248C CN B028277708 A CNB028277708 A CN B028277708A CN 02827770 A CN02827770 A CN 02827770A CN 100438248 C CN100438248 C CN 100438248C
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- Prior art keywords
- circuit breaker
- cut
- circuit
- important load
- load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/081—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current and depending on the direction
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- Supply And Distribution Of Alternating Current (AREA)
Abstract
The present invention discloses a protective relay in a circuit breaker system for the configuration and the connection of a connecting point between a commercial side bus and a power supply side bus for an important load. When the commercial power supply side has an open-circuit accident, the arrangement of a reverse power detecting device enables a circuit breaker for connection to operate to prevent reverse power from flowing out to protect an important load; in addition, whether directional short circuit element action (a short circuit accident) occurs on a load side or not is judged to enable the circuit breaker for connection to operate when the short circuit accident occurs on a common load side; when the judging result indicates that the short circuit accident occurs on an important load side, the circuit breaker for connection is not driven to operate, and thus, the important load can be protected.
Description
Technical field
The present invention relates to protection relay, particularly the system that uses in the system of important loads such as commercial side bus and house generator side bus with the tie point configuration circuit breaker of mains side bus is connected the protection relay of usefulness.
Background technology
In constituting, uses in the circuit of Fig. 5 the protection relay of system's connection usefulness in the past.This figure adopts line chart for simplicity, and the circuit that is actually with phase three-wire three constitutes.In Fig. 5,1 expression house generator, the 2nd, the house generator side bus, 3 expressions are by the important load of house generator 1 power supply.In addition, the intake of 4 expression commercial powers, the 5th, commercial side bus, 6 expressions utilize the general load of the commercial power power supply of being introduced by intake 4.House generator side bus 2 utilizes to be connected with circuit breaker 7 with commercial side bus 5 and connects.8 and 9 is respectively voltage transformer and the current transformer that is provided with at the electric wire from commercial side bus 5 to commercial power intake 4.The 10th, protection relay utilizes the voltage and the electric current that are taken into by voltage transformer 8 and current transformer 9, detects under voltage key element and direction short circuit key element, when detecting fault such as short circuit accident, cut-offs signal to circuit breaker 7 output circuit breakers.
The following describes its action.As mentioned above, house generator side bus 2 is to be connected by circuit breaker 7 with commercial side bus 5, connects with the action of circuit breaker 7 to be controlled by protection relay 10.Protection relay 10 has under voltage key element (under voltage checkout gear) and direction short circuit key element (direction short-circuit detecting device), will be configured in being subjected on the electric side electric wire from commercial side bus 5 to commercial power intake 4 as voltage transformer 8 and the current transformer 9 that transducer uses.
The under voltage key element is to utilize voltage transformer 8 to detect after the magnitude of voltage of detected three-phase voltage reduces to be in below the certain value, moves when important load 3 one sides and general load 6 one sides are short-circuited accident.
Direction short circuit key element is the reactive power that detects to the converting equipment outflow of commercial power, moves when the converting equipment of Utilities Electric Co. is short-circuited accident.
Therefore, when the open circuit accident takes place the intake 4 of commercial power,, therefore might connect and be failure to actuate with circuit breaker 7 because the direction short circuit key element of protection relay 10 is failure to actuate.At this moment, house generator 1 will be born to general load 6 one sides power supply.Like this, house generator 1 is with overload running, and house generator 1 might damage.
In addition, for the short circuit accident 13 and 12 in important load 3 one sides and the generation of general load 6 one sides, the under voltage key element will be moved, and connect with circuit breaker 7 actions.When general load 6 one sides are short-circuited accident 12, connect with circuit breaker 7 by cut-offfing, the voltage that can suppress important load 3 descends.But, when important load 3 one sides are short-circuited accident 13, connect with after circuit breaker 7 actions, still supply with short circuit current from house generator 1, be in overload.Then, if utilize the branch line road 11 of opening circuit to cut-off, then become light condition, load restoration is normal.Because this a succession of action, the cogging of house generator 1 increases, so house generator 1 generation damage, can not protect important load 3.
Like this, in protection relay in the past, when source power supply side open circuit accident 13 important load side short circuit accidents, the situation of important load and house generator might take place to protect.
Summary of the invention
The present invention also can protect important load and the important load protection relay with power supply when source power supply side open circuit accident and important load side short circuit accident.In addition, in the present invention, comprise for example generating equipment such as house generator, fuel cell or the high whole power supplys such as source power supply of reliability with power supply as important load.
Protection relay of the present invention adds the inverse probability key element, makes to make to connect when source power supply side open circuit accident to use the circuit breaker action message.In addition, the voltage transformer that will use as the transducer of protection relay and the installation site of current transformer become in the commercial bus bar side that connects with circuit breaker, use the short circuit accident of its short circuit accident that can differentiate the important load side and general load-side.
When source power supply side open circuit accident, because important load is born power supply to general load with power supply, the voltage of supplying with important load might descend, and therefore connection is cut-off with circuit breaker, protects important load.
In addition; when important load side short circuit accident; utilization has the detection signal of directionless short circuit key element; differentiating it is the short circuit accident of important load side, and still the short circuit accident of general load-side is when short circuit accident has taken place the important load side detecting; connection is moved with circuit breaker; and the accident point that utilizes branch line to cut off the important load side with circuit breaker, making the overload recovering state is normal condition, avoids damage by such protection important load with power supply.
Promptly; the present invention disposes the protection relay that is provided with in the system of connection with circuit breaker at the commercial side bus that connects general load and the important load that is connected important load with the tie point of mains side bus; comprise the voltage of importing described commercial side bus respectively and the input unit of electric current; value according to described voltage and described electric current; detect from the important load inverse probability checkout gear of mains side bus to the opposite direction power outflow of commercial side bus; when described inverse probability checkout gear detects power outflow in the other direction; the 1st circuit breaker that the circuit breaker that output makes described connection cut-off usefulness with circuit breaker cut-offs signal cut-offs signal output apparatus; according to described voltage and described current value; have or not the outflow reactive power to judge that short circuit accident is the direction short-circuit detecting device that takes place at which place of described general load-side and described important load side by detection; and be judged as described short circuit accident when described general load-side takes place at described direction short-circuit detecting device; output makes described connection cut-off signal with the circuit breaker that circuit breaker cut-offs usefulness, is judged as described short circuit accident when described important load side takes place; do not make described connection cut-off signal output apparatus with the 2nd circuit breaker that circuit breaker cut-offs.
Another aspect of the present invention is to dispose the protection relay that is provided with in the system of connection with circuit breaker at the commercial side bus that connects general load and the important load that is connected important load with the tie point of mains side bus; comprise the voltage of importing described commercial side bus respectively and the input unit of electric current; according to described voltage and described current value; have or not the outflow reactive power to judge that short circuit accident is the direction short-circuit detecting device that takes place at which place of described general load-side and described important load side by detection; and be judged as described short circuit accident when described general load-side takes place at described direction short-circuit detecting device; output makes described connection cut-off signal with the circuit breaker that circuit breaker cut-offs usefulness, is judged as described short circuit accident when described important load side takes place; do not make described connection cut-off signal output apparatus with the circuit breaker that circuit breaker cut-offs.
Description of drawings
Figure 1 shows that the circuit diagram of a circuit example that adopts protection relay of the present invention.
Figure 2 shows that the internal structure pie graph of protection relay of the present invention.
Figure 3 shows that the key diagram in the judgement zone of the inverse probability key element of protection relay of the present invention and direction short circuit key element.
Figure 4 shows that protection relay of the present invention inverse probability key element, direction short circuit key element and under voltage key element the detection content and the protection content key diagram.
Figure 5 shows that the circuit diagram of a circuit example of employing protection relay in the past.
Embodiment
Example 1
To be control setting connecting source power supply side and important load with the protection relay that is connected the usefulness circuit breaker on the bus of mains side with protection relay of the present invention.Figure 1 shows that a circuit example of the system that adopts protection relay 14 of the present invention, Figure 2 shows that the internal structure of protection relay 14 of the present invention.In addition, in Fig. 1, for the identical formation of Fig. 5, then additional identical label is represented, omits its explanation here.In addition, as important load power supply of the present invention, for example comprise high source power supply of generating equipments such as house generator or fuel cell or reliability etc., so long as in the high supply unit of reliability is included in all, and in the following description, then enumerating house generator as important load with power supply is that example describes.
One of difference of the formation of Fig. 1 and above-mentioned example in the past shown in Figure 5 is that the voltage transformer 15 of the input usefulness of protection relay 14 and the installation site of current transformer 16 become in commercial bus 5 one sides that connect with circuit breaker 7.At this moment, connecting the state that does not have load to be connected with formation between circuit breaker 7 and voltage transformer 15 and the current transformer 16.Utilize this formation; when load-side is short-circuited accident; then differentiating it is the short circuit accident of important load side or the short circuit accident of general load-side; detecting is when the important load side is short-circuited accident; just connection is moved with circuit breaker; and the accident point that utilizes branch line to cut off the important load side with circuit breaker, making the overload recovering state is normal condition, avoids damage by such protection house generator.
In addition, as the 2nd of difference be, protection relay 14 has inverse probability key element (inverse probability checkout gear) and replaces the under voltage key element, and by like this, protection relay 14 of the present invention just has direction short circuit key element and inverse probability key element.The detection content that Figure 4 shows that these key elements goes into to protect content.As shown in Figure 4, the inverse probability key element is to detect from house generator side bus 2 to flow out the situation of power to commercial side bus 5, moves when the intake 4 of commercial power send electricity stopping.By having added the inverse probability key element, when the open circuit accidents take place for intake 4 that in the past can not detected commercial power, make its reliable Detection should the open circuit accident; allow and connect with circuit breaker 7 actions; in case non-return power flows out, suppress voltage and descend, protection important load 3 and house generator 1.
In protection relay 14; as shown in Figure 2, be provided with the value of voltage transformer 15 and current transformer 16 detected three-phase voltages and three-phase current as input and amplifying circuit 17 that their are amplified; the filter circuit 18 that the signal that amplifying circuit 17 is exported also only makes their assigned frequency component pass through as input; is A/D converter 19 with the analog signal of filter circuit 18 outputs as importing and carrying out mould/number conversion; and this signal that will be converted to digital quantity as input and according to them by supervision under voltage key element and inverse probability key element and the short circuit direction operation processing unit 20 of detection failure usually.
Below action is described.At first; input to the inside of protection relay 14 from the input variable of voltage transformer 15 and current transformer 16; amplifying circuit 17 and filter circuit 18 by protection relay 14 inside; be transformed to the input of A/D converter 19; be converted to numerical data with A/D converter 19 from analogue data; numerical data after the conversion is inputed to operation processing unit 20, carry out fault judgement with operation processing unit 20.When detecting fault, output makes connection cut-off signal with the connection that circuit breaker 7 cut-offs usefulness with circuit breaker, makes to connect and cut-offs with circuit breaker 7.
In the operation processing unit 20 of protection relay 14, according to the numerical data that is taken into from A/D converter 19, calculate the power that moves at tie point, carry out the judgement that the inverse probability key element is gone into short circuit direction key element.Figure 3 shows that their judgement zone.In Fig. 3, active power (just with negative) and reactive power (leading and hysteresis) as vertical axis, are represented the judgement zone of each key element with label 30.That is, enter when adding hatched scope 30 in two results of reactive power operation result and active power operation result, inverse probability key element and short circuit direction key element are moved respectively.At this moment Power arithmetic is to flow to the direction of house generator side bus 2 as positive direction from commercial side bus 5.As shown in Figure 3, be in merit Power arithmetic result action when negative about the inverse probability key element, and, be when the reactive power operation result is leading direction, to move about short circuit direction key element.During source power supply side open circuit accident,, therefore detect the inverse probability key element, cut-off with circuit breaker 7, prevent that inverse probability from flowing out, suppress voltage and descend by making like this to connect owing to supply with active power to general load 6 from house generator 1, thus protection important load 3.
As mentioned above; in this example; utilize the inverse probability key element to detect the overload of the house generator 1 that takes place because of source power supply side open circuit accident; make to connect and cut-off with circuit breaker 7; by this overload state is recovered rapidly; the voltage that suppresses house generator 1 descends, thus protection important load 3.
In addition, in this example, be to have illustrated that protection relay 14 has the situation of direction short circuit key element and these two key elements of inverse probability key element, but be not limited to this situation, also can be in order to detect the open circuit accident of source power supply side, and only have the inverse probability key element.
Example 2
In the circuit shown in the above-mentioned example 1, when general load 6 one sides are short-circuited accident 12,, therefore detect direction short circuit key element because reactive power detects as leading direction.So, in this example, cut-off with circuit breaker 7 by making like this to connect, prevent that reactive power from flowing out and voltage descends.
On the other hand, when important load 3 one sides are short-circuited accident 13,, therefore do not detect direction short circuit key element because reactive power detects as the hysteresis direction.At this moment, do not make to connect and cut-off, at the accident point of short circuit accident 13, owing to suppress electric current by house generator 1 supply by the electric current of source power supply side supply with circuit breaker 7, utilize branch line with the cut-offfing and the accident point of cutting-off of short-circuit accident 13 of circuit breaker 11, making load restoration is normal condition.By like this, can prevent house generator 1 damage, important load 3 and house generator 1 can continue operation.
In addition; the determination methods that whether takes place as short circuit accident 13; for example as shown in Figure 1; circuit breaker 11 is set in advance branch line protection relay (the indivedual protection with transducer and relay) 21; when label 13 places have an accident, because the short circuit direction key element of protection relay 14 does not detect this situation, therefore as long as detect the overcurrent key element with protection relay 21 with branch line; cut-off instruction to circuit breaker 11 outputs, circuit breaker 11 is cut-off get final product.In addition, in Fig. 1, power is provided with branch line protection relay 21 to circuit breaker 11, but this is in order to try hard to the cause of simplified electrical circuit diagram, in fact preferably each circuit breaker all to be provided with the branch line protection relay.
As mentioned above, in important load 3 one sides and general load 6 one sides be short-circuited accident 13 and 12 o'clock, which short circuit accident detects that the direction short circuit will usually differentiate be according to having or not, when important load 3 one sides are short-circuited accident 13, cut-off with circuit breaker 7 by not making to connect, can prevent house generator 1 damage, important load 3 and house generator 1 can continue this row.
In addition; in this example, be to have illustrated that protection relay 14 has the situation of direction short circuit key element and these two key elements of inverse probability key element, but be not limited to this situation; also can be in order to detect the short circuit accident of important load side or general load-side, and only have direction short circuit key element.
Example 3
In above-mentioned example 1 and 2, be that to cut-off signal with circuit breaker 7 output connections with circuit breaker be that example describes with the short circuit accident of the overload of high speed detection house generator and important load side and to connecting, and in this example, be that this connection is adopted the high-speed circuit breaker that can cut-off in the half period with circuit breaker 7, make standard-sized sheet break time high speed as piece-rate system.
If establish from fault cause beginning unusually to the operate time of protection relay 14 be below the 5ms, the connection that is made of high-speed circuit breaker is below the 11.4ms with the switch off time of circuit breaker 7; then the standard-sized sheet break time (time of from the fault detect to the circuit breaker, cut-offfing) since with they and represent; so can realize the action that 16.4ms is following, from fault enough 1 of energy take place and separate below the cycle.
Like this, in this example, owing to take place and therefore can protect the important load 3 of connection to realize separation below the 16.4ms from fault.
Example 4
In this example; except protection relay road in above-mentioned example 1 and 2 14 used direction short circuit key element and inverse probability key element; the under voltage key element that voltage descends during in addition again to operation processing unit 20 additional high-speed judgement accidents can suppress to descend to the influence of important load 3 because of voltage.Figure 4 shows that the detection content and the protection content of these key elements.
In the circuit shown in the example 1, in important load 3 one sides and general load 6 one sides be short-circuited accident 13 and 12 o'clock, any situation no matter, the under voltage key element is all moved.Thereby, only according under voltage key element action, can not differentiate which load-side accident that is short-circuited.
Therefore, in this example, utilize the detection of under voltage key element to detect the short circuit accident of load-side, and the short circuit accident that utilizes the detection of direction short circuit key element to differentiate this load-side is the important load side and the short circuit accident of which load-side of general load-side.
In addition, can detect the action of under voltage key element and the moving of these two key elements of action of direction short circuit key element respectively does, differentiating in the load is which load-side accident that is short-circuited, but also can use AND circuit, gets the logic product of under voltage key element and direction short circuit key element and differentiates.
In addition, the voltage of protection relay of the present invention descends to descending from voltage detection time and begins to below the 3.5ms, and makes up below the switch off time 11.4ms of example 3 described high-speed circuit breakers, and the standard-sized sheet break time of then coming example is below the 14.9ms.
Like this, in this example, take place and therefore can protect the important load 3 of connection to realize separation below the 14.9ms from fault.
In addition; in above-mentioned example 1～4; being that example describes to protection relay 14 input three-phase voltages and three-phase electricity flow valuve; but be not limited to this situation; about voltage owing to utilize line voltage, therefore can according to R-S reach mutually S-T mutually electricity obtain remaining T-R phase voltage mutually; so also can import two phase voltages, also can access same effect in this case.
Industrial practicality
As mentioned above, the relevant protective relay of the present invention can in being equipped with the unit of providing generating equipment for oneself The high speed detection under-voltage key element of using when being used as the commercial side bus of connection and house generator side bus, contrary Power key element and short circuit direction key element and the protective relay that the breaker of tie point is cut-off.
Claims (5)
1, a kind of protection relay is to dispose the protection relay that is provided with in the system of connection with circuit breaker at the commercial side bus that connects general load and the important load that is connected important load with the tie point of mains side bus, it is characterized in that, comprises
Import the voltage of described commercial side bus and the input unit of electric current respectively,
According to the value of described voltage and described electric current, detect the inverse probability checkout gear that flows out to the opposite direction power of commercial side bus with the mains side bus from important load,
When described inverse probability checkout gear detects that in the other direction power flows out, the output circuit breaker that makes described connection cut-off usefulness with circuit breaker the 1st circuit breaker that cut-offs signal cut-offs signal output apparatus,
Have or not according to described voltage and described current value, by detection and to flow out reactive power and judge that short circuit accident is the direction short-circuit detecting device that takes place at which place of described general load-side and described important load side, and
Described direction short-circuit detecting device be judged as described short circuit accident when described general load-side takes place, output makes described connection cut-off signal with the circuit breaker that circuit breaker cut-offs usefulness, be judged as described short circuit accident when described important load side takes place, do not make described connection cut-off signal output apparatus with the 2nd circuit breaker that circuit breaker cut-offs.
2, a kind of protection relay is to dispose the protection relay that is provided with in the system of connection with circuit breaker at the commercial side bus that connects general load and the important load that is connected important load with the tie point of mains side bus, it is characterized in that, comprises
Import the voltage of described commercial side bus and the input unit of electric current respectively,
Have or not according to described voltage and described current value, by detection and to flow out reactive power and judge that short circuit accident is the direction short-circuit detecting device that takes place at which place of described general load-side and described important load side, and
Described direction short-circuit detecting device be judged as described short circuit accident when described general load-side takes place, output makes described connection cut-off signal with the circuit breaker that circuit breaker cut-offs usefulness, be judged as described short circuit accident when described important load side takes place, do not make described connection cut-off signal output apparatus with the circuit breaker that circuit breaker cut-offs.
3, protection relay as claimed in claim 1 or 2 is characterized in that,
Judge that the under voltage checkout gear of short circuit accident has taken place certain in described general load-side and described important load side below also having the certain value that becomes regulation according to described voltage and described current value, by the magnitude of voltage that detects described commercial side bus
Described direction short-circuit detecting device has or not according to described voltage and described current value, by detection and flows out reactive power, judges and utilize the detected described short circuit accident of described under voltage checkout gear is at which place of described general load-side and described important load side to take place.
4, protection relay as claimed in claim 1 or 2 is characterized in that,
Described connection with circuit breaker by can constituting with the high-speed circuit breaker that the half period cut-offs,
If from fault cause beginning unusually to the operate time of described protection relay be below the 5ms, described connection is below the 11.4ms with the switch off time of circuit breaker, it is 1 below the cycle that the standard-sized sheet break time at this moment takes place from fault.
5, protection relay as claimed in claim 3 is characterized in that,
Described connection with circuit breaker by can constituting with the high-speed circuit breaker that the half period cut-offs,
If from fault cause beginning unusually to the operate time of described protection relay be below the 5ms, described connection is below the 11.4ms with the switch off time of circuit breaker, it is 1 below the cycle that the standard-sized sheet break time at this moment takes place from fault.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2002/011571 WO2004042883A1 (en) | 2002-11-06 | 2002-11-06 | Protective relay |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1618156A CN1618156A (en) | 2005-05-18 |
| CN100438248C true CN100438248C (en) | 2008-11-26 |
Family
ID=32310233
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB028277708A Expired - Fee Related CN100438248C (en) | 2002-11-06 | 2002-11-06 | Protective relay |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPWO2004042883A1 (en) |
| CN (1) | CN100438248C (en) |
| WO (1) | WO2004042883A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102097817A (en) * | 2010-01-06 | 2011-06-15 | 珠海兴业新能源科技有限公司 | Photovoltaic reverse power controller |
| JP2014017947A (en) * | 2012-07-06 | 2014-01-30 | Toshiba Corp | Network protector |
| CN102780233A (en) * | 2012-08-08 | 2012-11-14 | 中盛光电能源股份有限公司 | Large-scale distributed photovoltaic power station user-side grid countercurrent-preventive system |
| CN105071361B (en) * | 2015-08-18 | 2019-02-01 | 国网山东桓台县供电公司 | Power System Intelligent prevents unordered anti-power transmission device |
| KR102008150B1 (en) * | 2017-11-03 | 2019-08-08 | 한전케이디엔주식회사 | Decentralized power control apparatus |
| CN108199484B (en) * | 2018-02-09 | 2024-07-02 | 广东电网有限责任公司揭阳供电局 | Method and device for rapidly disaggregating ring network |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06209525A (en) * | 1993-01-05 | 1994-07-26 | Nishishiba Electric Co Ltd | System-linkage protection and detection apparatus |
| JPH06245389A (en) * | 1993-02-18 | 1994-09-02 | Shikoku Sogo Kenkyusho:Kk | Instantaneous voltage drop compensator |
| JPH0779533A (en) * | 1993-09-07 | 1995-03-20 | Nishishiba Electric Co Ltd | Grid interconnection protection device |
| US6107784A (en) * | 1996-12-26 | 2000-08-22 | Kabushiki Kaisha Toshiba | System interconnection protective device for non-utility generation equipment |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2380631A1 (en) * | 1977-02-09 | 1978-09-08 | Schlumberger Compteurs | DIRECTIONAL RELAY |
| JPH09285016A (en) * | 1996-04-11 | 1997-10-31 | Nissin Electric Co Ltd | Power equipment |
| JP3585804B2 (en) * | 2000-03-06 | 2004-11-04 | 三菱電機株式会社 | Direction determination method |
| JP2002095149A (en) * | 2000-09-13 | 2002-03-29 | Toshiba Corp | Semiconductor switch control device |
-
2002
- 2002-11-06 WO PCT/JP2002/011571 patent/WO2004042883A1/en active Application Filing
- 2002-11-06 JP JP2004549563A patent/JPWO2004042883A1/en active Pending
- 2002-11-06 CN CNB028277708A patent/CN100438248C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06209525A (en) * | 1993-01-05 | 1994-07-26 | Nishishiba Electric Co Ltd | System-linkage protection and detection apparatus |
| JPH06245389A (en) * | 1993-02-18 | 1994-09-02 | Shikoku Sogo Kenkyusho:Kk | Instantaneous voltage drop compensator |
| JPH0779533A (en) * | 1993-09-07 | 1995-03-20 | Nishishiba Electric Co Ltd | Grid interconnection protection device |
| US6107784A (en) * | 1996-12-26 | 2000-08-22 | Kabushiki Kaisha Toshiba | System interconnection protective device for non-utility generation equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2004042883A1 (en) | 2004-05-21 |
| CN1618156A (en) | 2005-05-18 |
| JPWO2004042883A1 (en) | 2006-03-09 |
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