Final Draft Report ASSESSMENT SUMMARY Hydro One Networks ...

Burlington TS Overload Protection/Load Rejection scheme(CAA ID Number: 2006-EX298)Continuous Rating and 2 PU Trigger Value(all ratings in MVA)Existing T6Effective until June 2008New T6 1In-service after June 2008Continuous 2 PU Continuous 2 PUT4 250 500 250 500T6 215 430 250 500T9 250 500 250 500T12 250 500 250 500Table 1: 2 PU Values for Burlington AutotransformersThe proposed scheme is to be located at Burlington TS and consists of an ‘A’ and ‘B’ logic controller. The ‘A’ controller isa SEL351 relay and the ‘B’ controller is a GE C60 relay. Both controllers are powered from the station’s 'B' battery supplyand initiate trips to existing Burlington 115 kV 'B' protections and 'B' SC11 capacitor protection. Each controller isconfigured according to an output tripping matrix to initiate a four step, sequential load rejection of the Burlington 115 kVloads as shown in Table 2 below. The four steps are initiated on a timed sequence, provided a 2 pu overload condition isdetected by both controllers based on an instantaneous overcurrent 50P operation plus a definite time delay as described insteps 1, 2, 3 and 4 respectively.Proposed steps for Burlington Overload Protection/Load Rejection schemeStep Time delay Circuits Tripped(Stations dropped)1 4.5 seconds B5G, B6G (Asea BrownBoveri, Guelph, Hanlon,Puslinch, Westover CTS,Dundas #2)2 plus 3 seconds(total delay = 7.5 secs)3 plus 2 seconds4Seenote 1(total delay = 9.5 secs)plus 2 seconds(total delay = 11.5 secs)B10, B11 (Gage TS)Remote trip/Transfertrip sent toGage TSExpected LoadRelief200 MVAB7, B8 (Bronte TS) Bronte TS 100 MVANo circuits tripped atBurlington TSB3, B4 (Newton TS and ElginTS)B12, B13 & SC11 (115 kVcapacitor)Dundas #2 TS, Brant TS,Powerline MTSDundas, Mohawk,McMaster and NewtonTSTable 2: Load Rejection Scheme Steps for Burlington TS(Total = 300 MVA)130 MVA(Total = 430 MVA)All 115 kV loadsupplied byBurlington isdroppedNote 1: Step 4 is not expected to be used except in a worst case scenario involving equipment failure during planned outageconditions.The proposed scheme will be armed/disarmed from the NMS Operator Console at Hydro One's OGCC. Each controller hasits own supervisory control and status alarm. The operating status of each controller is immediately observable through astatus alarm at the NMS Operator Console.1 Hydro One is proposing modifications at Burlington TS which include replacing T6. That report will be available at CAA report #2006-EX299.