JBC, JBCG & JBCV. Phase & Ground O/C. Directional overcurrent protection of feeders and transmission lines. GE Multilin 1. Protection and Control

Transcription

1 JBC, JBCG & JBCV hase & Ground O/C JBC relay JBCG relay JBCV relay irectional overcurrent protection of feeders and transmission lines. Features and Benefits Mechanical targets inverse time/current characteristics rawout case Applications irectional phase fault protection (JBC) irectional ground fault protection (JBCG) istinguish phase faults from overloads/power swings (JBCV) rotection and Control Time overcurrent Instantaneous overcurrent Voltage-restrained phase overcurrent GE Multilin

2 ALICATION The JBC, JBCG and JBCV relays consist of three units, an instantaneous power-directional unit (bottom) of the induction-cup type, a time overcurrent unit (middle) of the induction-disk type, and an instantaneous-overcurrent unit (top) of the induction-cup type. The directional-unit contacts control the operation of both the instantaneous and the time-overcurrent units (directional control). In this application, the instantaneous unit provides high-speed protection for close-in high-current faults. hase Faults JBC The JBC relays are frequently applied for phase-fault protection of a single line. Typical external connections of current and potential transformers are shown in Figure. With this connection, the current (at unity-power-factor load) leads the polarizing potential by 90 degrees. ince the directional unit has a 4 degrees characteristic, its maximum torque will occur when the fault current (balanced -phase fault) lags its unity-power-factor position by 4 degrees. Typical internal connections are shown in Figure. Ground Faults JBCG The JBCG relay, with both time and instantaneous units directionally controlled, is designed for protection against ground faults and is therefore of lower operating current range. The relays used for such protection usually have a low-range operating coil which is rated either or A and A is also available. The directional unit of the JBCG is dual polarized and may be polarized by current alone, voltage alone, or by both simultaneously. This dual polarization is desirable on applications where both current and potential polarizing sources are available and there is a possibility that one or the other source may be temporarily lost. Typical internal connections are shown in Figure. hase Faults JBCV The JBCV relay is applied for phase-fault protection when it is necessary to distinguish between fault conditions and overload or power swings. The voltage restraint feature of the relay makes this distinction possible. When the generation at a given station is apt to vary from time to time, it is possible that the maximum load current may exceed the minimum fault current. When this occurs the JBC relay will not distinguish between a heavy load with maximum generation and a fault with minimum generation. This is a typical application for the JBCV relay. When a fault occurs with minimum generation, the restraint torque in the directional unit collapses rapidly as the voltage drops, thus permitting the relay to trip at the low value of fault current. On the other hand, the relay is prevented from tripping on heavy-load currents with maximum generation as the directional unit will not pick up due to the system voltage being maintained. Long or heavily loaded lines, that are operating near the stability limit, are subject to severe power swings. These power swings appear to the relay as traveling faults. ince the voltage is maintained near normal during a power swing, the JBCV relay is less likely to trip than would a relay without voltage restraint. General Inverse Time Characteristics are preferred where fault current magnitude depends largely upon system generating capacity at time of fault. Very-inverse and Extremelyinverse Time Characteristics are preferred where fault current magnitude is dependent mainly upon location of fault relative to relay and only slightly upon system generation setup. Target seal-in-units are provided for the time and instantaneous overcurrent units and are rated 0./.0 A, or 0.6/.0 A. Table. irectional Instantaneous Unit Ratings Col. Range 0-80 Table. Non-irectional Instantaneous Unit Ratings Range etting ick-up Range Connection and Range 6- Low (eries) 6-0 ➀ 0. High (arallel) 0- ➀ 9.6 CONTACT ec Rating Contin. sec Rating Rating The current-closing rating of the induction unit contacts is 0 A for voltages not exceeding V. Their current-carrying rating is limited by the tap rating of the seal-in unit. Available ettings Contin. Current Rating eries -8 arallel eries arallel ➀ This range is approximate, which means that 6-0 and 0- might actually be 6-8 and 8-. However, there is at least a A overlap between the maximum Low setting and the minimum High setting. : 0., 0.6, 0.7, 0.8,,.,.,,.,, 4 :.,,.,, 4,, 6, 7, 8, 0, :,.,, 4,, 6, 7, 8, 0,, 6

3 Connection iagrams Fig.. Typical external connections for three single-phase JBC relays for directional phase-fault protection of a single line A-C BU H H X X C C OC OC OC C TRI BU 7 8 ( + ) NOTE: RELAY OERATE FOR a FAULT IN IRECTION OF TC ARROW. ( - ) 67 - IRECTIONAL OVERCURRENT RELAY -TIME OVERCURRENT UNIT -INTANTANEOU OVER- CURRENT UNIT -IRECTIONAL UNIT TC - TRI COIL MILAR CIRCUIT FOR OTHER TWO RELAY OC-IRECTIONAL OERATING COIL C-IRECTIONAL OLARIZING COIL -EAL-IN WITH TARGET - OWER CIRCUIT BREAKER a - AUXILIARY WITCH, CLOE WHEN BREAKER I CLOE Fig.. Internal connections for JBCM and JBCM relays (07A674-0) C C C4 RE JUMER LEA WOUN HAING COIL BOT. C 4 C C 6 OER 7 C 8 8 R 9 0 C OT. OL C - INTANT. OVERCURRENT UNIT (TI) - TIME OVERCURRENT UNIT (MI) - IRECTIONAL UNIT (BOT) - EAL-IN UNIT = HORT FINGER Table. Time overcurrent unit taps and ratings Tap Range Characteristics ec Rating Continuous Rating Minimum Tap Maximum Tap Inverse () 70.6 Very inverse () 40 4 Extremely inverse (77). 0 Very inverse () 0 0. Extremely inverse (77) 9. 0 Inverse () 8 0 Fig.. Internal connections for JBCGM and JBCGM relays (07A69-0) C C RE JUMER LEA WOUN HAING COIL C BOT. C4 C C 8 C C OER C CURR. C4 OL. THYRITE TRANF. 9 C 0 4 OT. OL - INTANT. OVERCURRENT UNIT (TI) - TIME OVERCURRENT UNIT (MI) - IRECTIONAL UNIT (BOT) - EAL-IN UNIT = HORT FINGER

4 election Guide Minimum.U. Greater Than Full Load Frequency Time O/C ir. Inst. Approx. Wt. Unit Unit Non-ir. Tripping Case in lbs (kg) Inst. Unit Contacts Inverse Time Very Extremely ize Inverse Time Inverse Time Net hip JBC, HAE-TYE, 0 V, 0./.0 A TARGET AN EAL-IN UNIT JBCMA JBC77MA JBCMA (.4) (.7) JBCMYA N.O MYA (.) JBCMA JBC77MA JBCMA (.4) JBCMA JBC4MA JBC78MA JBCMA JBC4MA JBC78MA JBCG, GROUN-TYE, 0 V, 0./.0 A TARGET AN EAL-IN UNIT JBCGMA JBCGMA JBCG77MA 0-80 MA MA MA MA MA N.O M6A M6A MA M6A JBCGMYA JBCGMYA MYA MYA N.O MYA M4YA MYA JBCGMA JBCGMA JBCG77MA 0-80 M4A M4A M4A M7A M7A N.O M8A M8A M7A M8A JBCGMA JBCG4MA JBCG78MA 0-80 MA MA MA MA MA M6A M6A MA M6A JBCGMA JBCG4MA JBCG78MA 0-80 M4A M4A M4A M7A M7A M8A M8A M7A M8A (.4) 6 (6.) (.7) (.7) (.) (.6) (.) (.) (.) 4

5 Frequency Time O/C ir. Inst. Approx. Wt. Unit Unit Non-ir. Tripping Case in lbs (kg) Inst. Unit Contacts Inverse Time Very Extremely ize Inverse Time Inverse Time Net hip JBCG, GROUN-TYE, 0 V, 0.6/.0 A TARGET AN EAL-IN UNIT JBCGM9A M0A MA (.4) (.7) M4A JBCGMYA N.O M6YA JBCGM9YA M0YA (6.) (.6) M7YA M8YA JBCGMA MA N.O MA (.4) (.7) M6A election Guide hase-type Voltage Restrained Freq. Time O/C Unit ir. Inst. Unit Non-ir. Inst. Unit ir..u. at Rated Volts Minimum.U. Less Than Full Load Inverse Time Very Inverse Time Extremely Inverse Time JBCV, HAE-TYE, (ir. Unit with Voltage Restraint), 0 V, 0./.0 TARGET AN EAL-IN UNIT JBCVMA JBCV77MA MA MA JBCVMA N.O. MA JBCVMA M4A Case ize Approx. Wt. in lbs (kg) Net hip JBCVYA (6.) (.6) Tripping Contacts JBCV4MA JBCV78MA MA MA JBCVMA MA JBCVMA M4A Frequency Time O/C ir. Inst. Approx. Wt. in lbs Unit Unit C Aux. Tripping Case (kg) (V) Contacts Inverse Time Very Extremely ize Inverse Time Inverse Time Net hip JBC, HAE-TYE, 0 V, 0./.0 A TARGET AN EAL-IN UNIT JBCA JBC77A JBCA N.O JBCA JBC77A 4 JBCA (.4) (.7) JBCA JBCA (.) (.)

6 JBCG6 & JBCG6 Application These ground directional overcurrent relays are primarily for use in the transferred tripping schemes for highspeed protection of transmission lines. The basic schemes are:. irect underreaching. ermissive underreaching. ermissive overreaching The JBCG6 and the JBCG6 relays are similar respectively to the JBCG and the JBCG relays. However, the JBCG6 and the JBCG6 relays differ in the arrangement of the seal-in unit contacts and in the location of the directional unit contacts. Both contacts of the seal-in unit are connected to separate relay terminals, and the directional unit is arranged so that it can be used independently. election Guide 0 V, Hz (Continuous) 0.6/.0 A Target and eal-in Unit Time O/C Unit ir. Inst. Unit Tripping Contacts 0-80 MA MA MA N.O M4A MA M4A Approx. Wt. in lbs (kg) Case ize Inverse Time Very Inverse Time Net hip JBCG6MA JBCG6MA (.4) 6