CN1120255A - Overcurrent protection circuit and apparatus using thereof - Google Patents
Overcurrent protection circuit and apparatus using thereof Download PDFInfo
- Publication number
- CN1120255A CN1120255A CN95108309A CN95108309A CN1120255A CN 1120255 A CN1120255 A CN 1120255A CN 95108309 A CN95108309 A CN 95108309A CN 95108309 A CN95108309 A CN 95108309A CN 1120255 A CN1120255 A CN 1120255A
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- CN
- China
- Prior art keywords
- current limiting
- phase
- limiting fuse
- overcurrent protection
- load switch
- 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.)
- Granted
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Classifications
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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
- H02H3/083—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 for three-phase systems
-
- 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
- H02H3/093—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 with timing means
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- Emergency Protection Circuit Devices (AREA)
- Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
- Fuses (AREA)
Abstract
The overcurrent protection circuit has current limiting fuses (6A-6C) for three phases and a disconnection switch (5) is connected to these fuses. The circuit also includes a delay unit (8) to excite a trigger coil (9) and to open the disconnection switch (5). After this, fuse signals are input into the remaining fuses and operate relays for the other phases when a fuse signal for at least one phase is input into a fuse.
Description
The present invention relates to an overcurrent protection loop, it is combined by current limiting fuse and an on-load switch, in order to the protection electric loop.
Because short circuit current can not only cut off with on-load switch, provide a kind of cost effective device by current limiting fuse and an on-load switch combination, in order to cutting-off of short-circuit electric current and protect electric loop.The damage scope of current limiting fuse is time of being passed through by overcurrent and the number of times that repeats to pass through decision.In this scope, can not give the fusing seen or mutually blocking might take place.In addition; in the basic application of current limiting fuse; owing in the smaller fusion current scope in the pre-arcing characterisitics of current limiting fuse, be bigger, so current limiting fuse only is used for protecting short circuit because the variation of overcurrent makes the variation of fusing time and change.Overcurrent is by other device basically, protects as the three-phase load switch.
The characteristic of the current limiting fuse of speaking of has above illustrated in the standard by current limiting fuse.For example, the 4th page of inverse the 4th to 9 row in the C4606-1988 of the JIS of Japanese Industrial Standards, the variation of the characteristic of current limiting fuse allows ± 20%.
Then, on-load switch cut-offs characteristic with what current limiting fuse used, the characteristic of cut-offfing that particularly shows connecting-disconnecting function, under the loop condition by defined in standard, the current limit value that can cut off is represented, for example, being defined in the power factor that load current cut-offs the load in the test the 17th page of CA605-1987 is 0.65-0.75.And cut-offfing characteristic also is fixed in this power factor scope.
Cut-offfing characteristic (for example the power factor of an exciting current approximates 0.1) under exceeding other power factor of above-mentioned power factor scope is shown in the following table.
Table (unit: ampere)
In the table, for the 1st) the kind situation, power factor is 0.65-0.75, for the 2nd) the kind situation, its power factor is lower than situation 1) numerical value, in JISC4605-1987 17 pages first the row in explanation.
| Rated current | ??100 | ??200 | ??300 | ??400 | ??600 |
| 1) rated load current breaking capacity | ??100 | ??200 | ??300 | ??400 | ??600 |
| 2) specified exciting current connecting-disconnecting function | ??5?? | ??10 | ??15 | ??20 | ??30 |
| 3) specified charging current connecting-disconnecting function | ????????????????????10 | ||||
Can see that by this table specified exciting current connecting-disconnecting function is reduced to 1/20 of load current connecting-disconnecting function basically.Fig. 4 in the 16th page of JISC4620-1992, and narrated in this standard the 30th page and adopted the wiring and the loop element of the PF.S form of a current limiting fuse and an on-load switch to be connected tie lines.Wherein talk about; can be called striker by one; the melt coupling part of current limiting fuse; in the time of melt fusing, carry out and give fixed mechanically actuated operation; tripping on-load switch mechanically and automatically; make the expanded range of drop-out current, and realize because the current limiting fuse fusing causes the protection of cut-offfing mutually.
If at phase fault, for example short circuit between a Circuit Fault on Secondary Transformer part and MCCB (mould case circuit breaker), short circuit current flows in the secondary side part of this transformer, and overcurrent also flows in this transformer primary side part.Then the three-phase load switch is opened at current limiting fuse fusing back 0.05-0.2 second.
But because primary side part overcurrent numerical value is in little fusion current scope, fusing time has the 0.3-1.5 wide variation of second.In the short circuit of the secondary side of transformer, even the three-phase load switch is to be opened by the striker of the current limiting fuse of fusing when only having one in the middle of the three-phase to be melted mutually.In addition, in on-load switch, utilize the switch of other phase that fuse do not fuse to go to cut-off overcurrent.
Although the power factor of primary side part overcurrent changes according to the condition of transformer when Circuit Fault on Secondary Transformer partly is short-circuited,, power factor approximates 0.1 usually.The situation that equals 0.1 for power factor is because this power factor value has exceeded the characteristic of on-load switch, so overcurrent just can not be cut-off.
Then, confirmed that by test the probability that the catastrophe failure of this phase fault takes place is low, because on-load switch can not cut-off overcurrent under these conditions.
The present invention is considering that some above-mentioned problems make later on, and purpose is to provide the overcurrent protection loop of a safety, in order to prevent producing arc short circuit in the three-phase load switch.
Overcurrent protection of the present invention loop will be from the maximum of current limiting fuse extending to during this period of time of being melted to that an on-load switch begins to move above the fusing time of the dispersion of current limiting fuse.
Therefore,, avoided to cut-off and phase fault, thereby improved the fail safe in overcurrent protection loop because three-phase load switch of the present invention is just to open after all three-phase current limiting fuses all melt.
Fig. 1 illustrates the overcurrent protection loop of one embodiment of the present of invention.
Fig. 2 illustrates the overcurrent protection loop of another embodiment of the present invention.
Fig. 3 is the characteristic curve that is shown in the current limiting fuse among Fig. 1.
Fig. 4 is the current limiting fuse sectional arrangement drawing that is shown in Fig. 1.
Fig. 5 is the current limiting fuse sectional arrangement drawing that is shown in Fig. 2.
By having confirmed the following fact in the alternate arc short circuit test of the on-load switch that is used for the overcurrent protection loop.
(1) will receive the load side of on-load switch and current limiting fuse as transformer, motor etc., make under the situation that the power factor in loop reduces, in fault, phase fault take place sometimes.
(2) when every phase current limiting fuse has the variation of fusing time as shown in Figure 3, phase fault can take place.
For example a fuse in the three-phase current limiting fuse at first melts in short trouble, subsequently, and a three-phase load switch opens.But, owing to the current limiting fuse of other two-phase is in the process of fusing, and there is the transformer of a low power factor to receive secondary side again, make the power factor in overcurrent protection loop be lower than general loop.
Usually, the characteristic of on-load switch is to cut-off operation in the scope of 0.65-0.75 to set according to power factor.When power factor was lower than this scope, because the difference of voltage-phase and current phase, drop-out current significantly reduced.Confirm, reduce in power factor, and under the infusible condition of current limiting fuse, when the on-load switch of linking the current limiting fuse that is in fusion process cut-offs, phase fault can take place.Because on-load switch can not fully disconnect electric arc.
Prevent the embodiment of phase fault with the present invention referring to figs. 1 through Fig. 3 explanation.Fig. 1 and Fig. 2 provide overcurrent protection of the present invention loop, and Fig. 3 provides the pre-arcing characterisitics curve, and wherein transverse axis is represented fusing time t, and the longitudinal axis is represented fusion current i, and chain-dotted line is represented the tolerance limit of pre-arcing characterisitics.There is the structure of the on-load switch of current limiting fuse to illustrate by Fig. 4 and Fig. 5 respectively at each overcurrent protection loop band.
The secondary side part 1A of transformer 1 links a plurality of loads, as linking motor 3 through the circuit 2 of supplying with load.For load side, these loops have low power factor, because picture phase modulator, motor 3 and transformer 1, they all are connected with one separately from reactance.
Be connected with three-phase load switch 5 and current limiting fuse 6A, 6B and the 6C fusing time for current limiting fuse 6 between the electric power system 4 of the primary side 1B of transformer 1, for example, 6A under fusion current i1, is distributed in the t1-t2-t3 scope as shown in Figure 3.When the striker 6D of current limiting fuse 6A action, 7 actions of first time-delay relay, electric current flows into timing circuit 8, and breaking coil 9 is by excitatory, and on-load switch 5 is opened.Wherein numeral 10 is represented DC power supply.
When one short trouble takes place the O place in load circuit 2, just there is short circuit current to flow through.Current limiting fuse 6A fusing then, the striker 6D of fuse 6A ejects along the direction of arrow among the figure.But owing to have electric current to flow through at the fusing time t2 of current limiting fuse 6B and 6C and the time t4 after the t3 in the timing circuit 8, excitation and breaking coil 9 are opened on-load switch 5, and the fail safe in this loop is greatly improved.
In addition, in case and current limiting fuse 6A, 6B and 6C are at same fusing time t5, corresponding fusion current i1, i2 and i3 melt simultaneously, the second relay 7X action of all phases, energization of trip coil 9, open on-load switch 5 immediately, just can prevent to enlarge, also improved the fail safe in loop simultaneously in the load side accident.
Can explain the concrete structure of the three-phase load switch 5 that is shown in Fig. 2 with reference to Fig. 4.Because it is the structure of three-phase is identical, existing to (or the structure of the overcurrent protection formed of the on-load switch with delay function describes by current limiting fuse 6A and the on-load switch that is attached thereto.
Current limiting fuse 6A is removably mounted between load side terminal 6F and the power supply side terminal 6E, and two terminals support by insulator 6G.After current limiting fuse 6A fusing, striker 6D ejects along the direction of arrow among the figure, and operating mechanism part 20 actions of on-load switch 5 will discharge with the engagement of locking device 21.Moving contact 22 counter rotations that contact with the fixed contact (not shown) disconnect the connection between terminal 6E and the electric power system 4.
After striker 6D ejected along the direction of arrow among the figure, bar 25 moved along diagram chain-dotted line direction, and insulating bar 27 is owing to connecting rod 26 counterclockwise rotates and direction motion left.Relay bar 28 continues to promote first time-delay relay 7 in relay axle 28X rotary course.Then, after time t4, electric current flows through timing circuit 8 and energization of trip coil 9, and breaking coil 9 promotes locking device 21 again along clockwise direction.Figure repeat circuit axle 28X just is fixed on the chassis 40 then.
Locking device 21 is rotated in a clockwise direction by the supporting of locking device axle 21X, and locking device hook portion 21B is released off out with keeping bar axle 29.Then, when keeping bar 29 under retainer shaft 29X supporting, to rotate, keep connecting rod 29B and insulating bar 29C counterclockwise to rotate, and by counterclockwise rotate with arc control device 30 in the moving contact 22 that contacts of fixed contact cut off being connected between terminal 6E and the electric power system 4.Electric power system 4 is connected to the terminal 6E of mains side by the electric connecting member 22A that is connected to moving contact 22.
Because for the situation that moving contact 22 contacts with fixed contact, each element is as long as move as the opposite direction of arrow among the above-mentioned figure, and therefore, the situation of rightabout action has not just made an explanation.
For the structure of the on-load switch 5A that is shown in Fig. 5, omitted with the explanation of components identical in the on-load switch that is shown in Fig. 4, only different element among explanation and Fig. 4.
Promptly be that relay bar 28 rotates the bar 31 on axle 31X with relay axle 28X in the process that serves as the axle rotation.And promote a damper 32.The bar 31 of 32 pairs of rotations of damper works behind time t4, as timing circuit 8, the rotation of bar 31 makes locking device 21 motion, and as action as described in above-mentioned Fig. 4, because the moving contact 22 that contact with fixed contact, cut-offs being connected of terminal 6E and electric power system 4 counterclockwise to move.
Because for the situation that moving contact 22 contacts with fixed contact, each element is as long as the situation of action is in the other direction no longer explained in the direction action opposite as arrow among the above-mentioned figure.
The composition of operating mechanism part 20 is simple and easy to be formed, and has improved the efficient of assembling at 20 o'clock.This is to form 20 parts owing to can be used in the way of equipment damper 32 on 20 the part.
According to the present invention, because the three-phase load switch is just to open, therefore, can prevent to be electrically connected the possibility that to cut-off or the possibility that phase fault takes place after the current limiting fuse of three all phases all melts, thereby improve the fail safe in loop.
Claims (10)
1. the overcurrent protection loop of an on-load switch (5) that has three-phase current limiting fuse (6A-6C) and be attached thereto, described overcurrent protection loop comprises:
Time-delay mechanism (8), when the fusing signal that has a phase at least is input to current limiting fuse, and also be input to still current limiting fuse in other phase that retains at the fusing signal, and after the relay of other phase also moves, this time-delay mechanism is in order to energization of trip coil (9), and opens described on-load switch (5).
2. according to the overcurrent protection loop of claim 1, also comprise: the switch opens device, when all fusing times of described current limiting fuse are basic identical, in order to energization of trip coil (9) and open described on-load switch (5).
3. according to the overcurrent protection loop of claim 1; wherein said time-delay mechanism (8) at least one fusing in the described current limiting fuse (6A-6C) of three phases; and after at least one striker (6D) of described current limiting fuse (6A-6C) ejects; the current limiting fuse of other phase that all retain also melts; after the striker of described other phase (6D) also ejects, encourage described breaking coil (9) and open described on-load switch (5).
4. according to the overcurrent protection loop of claim 1, one of them three-phase load switch is used as described on-load switch.
5. according to any one overcurrent protection loop in the claim 1 to 3; wherein by the fusing time of a current limiting fuse of current limiting fuse of fusing and last fusing at first in the described current limiting fuse of three phases, and the time-delay of the decision operate time of striker (6D) is set to described time-delay mechanism (8).
6. according to any one overcurrent protection loop in the claim 1 to 3, wherein have electric capacity and self-induction at least, be connected to the secondary side of described on-load switch and described current limiting fuse (6A-6C) in order to a loop of causing the drop-out current time-delay.
7. overcurrent protection loop comprises:
A moving contact of every phase (22), electric the going up of one end links to each other with power supply side terminal (6E), and the other end of described moving contact (22) is connected with described power supply by an operating mechanism part 20 or disconnects;
A current limiting fuse of every phase (6A) is inserted in the middle of described power supply side terminal (6E) and the load side terminal (6F);
A striker of every phase (6D) is provided on the described load side terminal (6F), and when one of them melted mutually in the three-phase current limiting fuse (6A-6C), the striker of corresponding described phase ejected;
A relay of every phase (7) is operated by described striker (6D);
After all strikers eject, by the time-delay mechanism (8) of described relay (7) startup
Wherein said time-delay mechanism (8) excitation makes the breaking coil (9) of described operating mechanism part (20) action, and described moving contact (22) is made it by the action of described operating mechanism part (20) and disconnects on the fixed contact of mains side is electric.
8. overcurrent protection loop comprises:
A moving contact of every phase (22), one end are linked power supply side terminal (6E), and the other end of described moving contact (22) is made it and described power connection or disconnection by operating mechanism part 20;
Each current limiting fuse (6A-6C) inserts between described power supply side terminal (6E) and the load side terminal (6F);
A striker of every phase (6D) is provided on the described load side terminal (6F), and after at least one fusing in the three-phase current limiting fuse (6A-6C), the striker of corresponding described phase (6D) ejects;
Relay (7) by described striker (6D) operation;
The damper of operating by the action of described relay (7) (32), before preventing that in the end the striker of the current limiting fuse of a fusing ejects, described operating mechanism part (20) action;
9. according to the overcurrent protection loop of claim 7 or 8, wherein a three-phase load switch is as described on-load switch.
10. according to the overcurrent protection loop of claim 7 or 8, a loop that wherein has electric capacity or self-induction at least is connected to the secondary side of described on-load switch and described current limiting fuse (6A-6C).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP132771/94 | 1994-06-15 | ||
| JP13277194A JP3293327B2 (en) | 1994-06-15 | 1994-06-15 | Overcurrent protection circuit and its device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1120255A true CN1120255A (en) | 1996-04-10 |
| CN1047481C CN1047481C (en) | 1999-12-15 |
Family
ID=15089177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95108309A Expired - Fee Related CN1047481C (en) | 1994-06-15 | 1995-06-14 | Overcurrent protection circuit and apparatus using thereof |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JP3293327B2 (en) |
| KR (1) | KR960002403A (en) |
| CN (1) | CN1047481C (en) |
| DE (1) | DE19521497A1 (en) |
| FR (1) | FR2721433B1 (en) |
| TW (1) | TW269062B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100460622B1 (en) * | 2001-11-06 | 2004-12-09 | 한국전력공사 | The apparatus of transformer with a built-in switch |
| NL1021022C2 (en) * | 2002-07-08 | 2004-01-09 | Pooltechnics B V | Drive assembly for switching a motor on and off comprises transformer with at least one primary winding and at least one secondary winding, transformer being arranged so that its emits lower voltage than alternating voltage |
| FR3021465B1 (en) * | 2014-05-21 | 2016-06-10 | Mft D'appareillage Electrique De Cahors | PROTECTIVE BLOCK FOR A LOW VOLTAGE PROTECTION CIRCUIT BREAKER, IN PARTICULAR POWER SUPPLIED BY A POLE TRANSFORMER |
| CN108400040B (en) * | 2018-05-08 | 2024-05-14 | 佛山职业技术学院 | Main and standby power supply switching device with time delay protection |
| KR102246003B1 (en) * | 2019-03-20 | 2021-04-29 | 한주현 | Automatic Fault Isolation Device System of 3 Phase Batch Open by electric control |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1126976B (en) * | 1958-11-14 | 1962-04-05 | Siemens Ag | Protective device against premature activation of an overcurrent multi-phase switch-disconnector |
-
1994
- 1994-06-15 JP JP13277194A patent/JP3293327B2/en not_active Expired - Fee Related
-
1995
- 1995-04-19 TW TW084103841A patent/TW269062B/zh active
- 1995-05-19 KR KR1019950012508A patent/KR960002403A/en not_active Application Discontinuation
- 1995-06-13 FR FR9506991A patent/FR2721433B1/en not_active Expired - Fee Related
- 1995-06-13 DE DE19521497A patent/DE19521497A1/en not_active Withdrawn
- 1995-06-14 CN CN95108309A patent/CN1047481C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1047481C (en) | 1999-12-15 |
| JPH087720A (en) | 1996-01-12 |
| FR2721433B1 (en) | 1998-12-18 |
| KR960002403A (en) | 1996-01-26 |
| TW269062B (en) | 1996-01-21 |
| DE19521497A1 (en) | 1995-12-21 |
| JP3293327B2 (en) | 2002-06-17 |
| FR2721433A1 (en) | 1995-12-22 |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |