CT-1 CTD-1 CTA-1 TOROIDAL CURRENT TRANSFORMERS E F GENERAL CHARACTERISTICS 40 PROTECTION INSTRUMENTS

Transcription

1 T- T- T- TOROIL URRNT TRNSORMRS NRL HRTRISTIS The differential earth relays T- can be connected to the following toroidal current transformers. They must be crossed by the cables of the line to be controlled; insert the phases and neutral if present. The earth cable must NOT cross the current transformer. NOT: Twist the connection wires between the toroid and the relay, keep them away from the power cables, and in the presence of strong electromagnetic fields use a shielded lead. Separately twist the pair of signal cables (terminals -) from the control circuit pair (terminals -) where present. Reduce the distance between the toroid and the relay to the minimum. T-/8 ORR O IMTR ( mm ) OR WIHT ( kg ) T-/8 8 SOLI OR 0,00 Residual current transformer T-/8 TYP - IMSIONS ( mm ) T-/8 5,5 85, PROTTION INSTRUMNTS

2 T-/ ORR O IMTR ( mm ) OR WIHT ( kg ) T-/ SOLI OR 0,50 TYP - IMSIONS ( mm ) T-/ T-/5 T-/60 T-/80 T-/0 T-/60 ORR O IMTR ( mm ) OR WIHT ( kg ) T-/5 5 SOLI OR 0,0 T-/60 60 SOLI OR 0,80 T-/80 80 SOLI OR 0,50 T-/0 0 SOLI OR 0,50 T-/60 60 SOLI OR,50 H Ø5 TYP - IMSIONS ( mm ) H T-/ T-/ T-/ T-/ T-/ PROTTION INSTRUMNTS

3 T-/0 ORR O IMTR ( mm ) OR WIHT ( kg ) T-/0 0 SPLIT OR 0,600 H T-/60 Ø5 K ORR O IMTR ( mm ) OR WIHT ( kg ) T-/60 60 SPLIT OR,600 K 8 H TYP - IMSIONS ( mm ) H K T-/ T-/ ,5 50 PROTTION INSTRUMNTS

4 T-/0 T-/0 T-/00 T-/00 ORR O IMTR ( mm ) OR WIHT ( kg ) T-/0 0 SOLI OR,50 T-/00 00 SOLI OR,00 T-/0 0 SPLIT OR,850 T-/00 00 SPLIT OR,00 K H 5 TYP - IMSIONS ( mm ) H K T-/ T-/ T-/ T-/ PROTTION INSTRUMNTS

5 T-/80R T-/50R T-/5R ORR O IMTR ( mm ) OR WIHT ( kg ) T-/80R 80 x 50 SOLI OR,700 T-/50R 50 x 70 SOLI OR,00 T-/5R 00 x 50 SOLI OR 8,00 P K H Test TYP - IMSIONS ( mm ) H T-/80R T-/50R T-/5R PROTTION INSTRUMNTS

6 T T T THNIL HRTRISTIS T-/ T-/5 T-/60 T-/80 T-/0 T-/60 T-/0 T-/00 T-/8 T-/0 T-/60 T-/0 T-/00 T-/80R T-/50R T-/5R MINIMUM MSUR URRNT PPLITION OPRTIN TMPRTUR STOR TMPRTUR TRNSORMTION RTIO INSULTION TST m m m m m m m m m m m m onnected with earth leakage LR serie /,5kV for minute m m m PRMNNT OVRLO THRML OVRLO TYP O TRMINLS R O PROTTION RRN STNRS 000 0k for second screws with maximum cross section,5mm IP0 I-N 5008-, I-N5008-, I., I-N 6055, I/N NNX M T-M XTRNL MULTIPLIR TOROIL Toroidal multiplier to extend the current calibration of differential relays up to 50. L L L N To connect between toroid and relay. Reduces the current 0 times. Therefore, the range of the tripping set-point I n adjustment is multiplied by ONNTIONS Input terminals 5-6 of the multiplier must be connected respectively to terminals - of the toroid transformer on the controlled line. TM LR N.. No cables must pass through the external multiplier. T T-S XTRNL R TOROIL Toroidal adder to be used in cases where the conductors of the system to be protected exceed the inside diameter of the reducer. In this case they are used T /5 to be installed in line, which will be then connected to the toroid adder and from there to the differential. N L L L P P P P () 5 6 () TM LR PROTTION INSTRUMNTS 5

7 T- / PPLITION NOT TOROIL URRNT TRNSORMRS. PPLITION THROUH T.. PPLITION - This application is particularly useful in those cases, in which it is im possible to embrace all conductors (supply bars) of the system, with only one transformer. In this case, It is possible to have arth Leakage Protection, by using t s and one of our special toroid transformers (exclusively made by us, ba sed on the winding rate of the t s), complying with the wiring diagram, described below. or this application the t s should have: the same tran sformation ratio (5 secondary), same power (0 V at least) and class 0,5. On the other hand, it is important that the t s are mounted, in such a way that the script P is orientated upstream, towards the line to be protected, and the various secondaries exactly as per the diagram.. OPRTIN - When there is no earth leakage, the vectorial addition of the currents sensed by the t s, is equal to zero. Thence, there is no current flowing in the windings related to our terminals 5 and 6 (in our special toroid). The re isn t any voltage generated in our terminals and therefore, which should make the LR to trip. When there is a leakage, otherwise, the vectorial addition of the currents sensed by the t s is different to zero. Thence, a voltage is generated through the terminals and, making the LR to trip. or this application, it is advisable to have a tripping threshold of the LR, not lower than a /00 of the rated current of the system to be protected. P N L L L P P P () 5 6 () T-/S RLÈ IRNZIL. PPLITION WITH TRNSORMRS ROUN.. PPLITION - This application is particularly indicated when the system is supplied through Transformers, working in parallel. In fact, it could be impossible to protect the line with LR s sited imme diately downstream of the transformers. Since it wouldn t be possible to establish which part of the urrent Leakage to round (clg) is borne by one or the other transformer. This brings us to a point, in which is prac tically impossible to establish exactly the threshold of the tripping value of the relays. XMPL: Suppose that we wish to protect an installation, which requires that the LR should trip when the clg is equal to 5. Should we install LR s with 5 threshold, it would certainly be required a higher value of clg, in order to make the LR to trip. On top of the above, in case of an equal distribution of the current leakage between both transformers, it should be required a clg = 0, in order to make the LR s to trip. Otherwise, if we adjust the tripping threshold to.5, it could be the case that one transformer is bearing fl of the clg and the other only. Thence the LR of the first transformer would trip before the 5 of clg are reached. Other factor to be considered, is the eventual separation of a transformer from the parallel, during low load demand periods. In this case the eventual clg is totally re-closed through the earth of an unique transformer and the tripping threshold should be establish exactly as 5, under these condi tions. The solution of the problem is given in our diagram... OPRTIN - Our diagram here below shows the solution, based in connecting the star centres of both transformers together to earth with an unique wire, which has passed through our toroidal transformer before. It is based in the fact that any current leakage to ground can t be re-closed but through the star centres of the transformers. With the toroidal, positioned as per our diagram, it is measured therefore the total current leakage to ground. ack to the above mentioned example, we should establish as 5 the tripping threshold value, with the assurance that the LR will trip, when the clg goes above the 5 threshold. TR TR TRM TR TR TRM LR RLY RL L L L N L L L N RIO RIO 6 PROTTION INSTRUMNTS

8 T- / PPLITION NOT TOROIL URRNT TRNSORMRS. PPLITION ON VRIOUS LINS IN PRLLL.. PPLITION - This application can be used whenever there are various connecting lines through two bar systems OMNIUS. In this case, the use of LR s with their corresponding T/T s,per each con necting line, it could give operation inconveniences; since the vectorial addition of the currents, on each connecting line, might not necessarily be equal to zero. It could be the case that, with perfectly equal lines, there could be a difference of current distribution, due to a contact resi stance difference (in phase R, for example), whilst the adsorbed current by the load might be equally distributed, in the other lines. ll this brings along that, there might be a leakage signal, at the to roidals terminals -, which could be sufficient to make the LR s to trip, without any earth leakage. With this kind of distribution, it is advisable to go to the wiring diagram, in which there are used as many T/T s as connecting lines, all of them orientated towards the and terminals of our LR. This application is valid for a maximum of 6 Tt s con nected in parallel. In those cases, in which a higher number might be required,, it is advised to contact us. or this application, it is advisable to have a tripping threshold not below /000 of the nominal current of the system to be protected. L L L N.. OPRTIN - when there is no leakage, although with a non uniform current distribu tion, as mentioned in the above paragraph., the originated signal at the first toroidal, is totally void by the leakage signal originated at the second toroidal, since the signal can t be but in opposition, and the LR s terminals won t receive any signal and the LR won t trip therefore. Otherwise, when there is an earth leakage, independently of whatever it might be the current distribution, the signals summation, being measu red by the various Tt s, meet at the and terminals of the LR, which will trip therefore. L L L N Tn T T LR RLY RIO. MIUM VOLT LINS Should an LR be used in MV lines, it is advisable to use the built-in filter for third harmonic version. L L L N ROUN L L L N ROUN ig. ROUN ig. NOT If there is an earthing circuit, it should be placed outside of the T/T (fig). When the cable is fitted with a metallic screen and it gets through the T/T, the earthing connection should be as (fig. ). PROTTION INSTRUMNTS 7