Presentation on theme: "Closed Transition ATS’s"— Presentation transcript:
1 Closed Transition ATS’s John J. Stark Marketing Services Coordinator, Russelectric Inc.
2 Why Operate in Parallel with the Utility? Closed Transition Transfer of non-utility generator, re-transfer and generator testCogenerationPeak ShavingCurtailable Rate StructureDistributed GenerationI would expect most of you have a good idea why a facility would want to parallel with the utility.Since this discussion is based on parallel operation with the utility, lets take a second and quickly review the reasons one might parallel onsite generators with the utilityReviewLast item has gotten a lot of play these days particularly with deregulation and in many cases may be more attractive to the utility companies, than adding their own generating facilities..
3 Types of Operational Modes Open TransitionClosed Transition
4 First let’s talk about open transition mode An open transition mode of operation is a method of transferring a load between two sources with an interruption of power duringtransfer.
5 L L L E E E N N N M1 M2 Open transition ATS Motor #1 drives the normal source contactsOpen.M1This is all done with very reliable mechanical interlocking and does not require an elaborate electrical interlocking design.The load source is disconnected for an adjustable period to allow regenerative power to decayMotor #2then drives the emergencysource contactsclosedM2
6 Closed Transition Mode A closed transition mode of operation is amethod of either:1) Transferring a facility’s load between the utility and generator or 2) operating a generator in continuous parallel with the utility service, without an interruption of service.
7 Utility ConcernsReliability and quality of utility power to other customersSafety and protection of utility service personnelProtection of utility equipment
8 Type of Parallel Operation Passive Momentary utility parallel operation100ms or lessThere are basically two types of parallel operation of a NUG (Non-Utility Generator) with the utility100 ms overlap is accepted by many utilities with no interconnection requirements at all.However, some utilities have some minimum requirements while still others treat it no differently than if the NUG were operated in parallel for an indefinite period of timeThe minimum requirements for short time operation in parallel could be a simple timing circuit that times out if the contacts are in parallel for a definite set period of time and send a signal to trip the utility breaker if this time is exceeded. Still others might have some minimum protective relay requirements such aas the use of a device 32 or 27/59.
9 L E L E L E N N N S1 S2 Closed Transition Operation Closed transition ATSLNELNELNEOperator #1drives thenormal source contactsopenS1The load source is connected to both sources momentarilyS2Operator #2drives the emergencysource contactsclosedClosed Transition Operation
10 Closed Transition Transfer Switches AdvantagesNo interruption of power for load test andreturn to utility as well as peak shave operationFast transfer operation
11 Closed Transition Transfer Switches DisadvantagesNo phase lock synchronizingNo Protective relaysNo mechanical interlock, thus no safe manual operationLacks true load test functionHigher fault current requirements
12 Full 3-Phase over and under voltage and frequency Sophisticated Controls and Safety FeaturesFull 3-Phase over and undervoltage and frequencysensing on both normal andemergency sources.Protection against running over100 msecs:Signals to operatorsFail to Transfer FunctionProvides trip signals to thegenerator or utility breakers.Our Switches are controlled by the MODEL 2000 Microprocessor Control System.It Features:Full 3-Phase over and under voltage and frequencysensing on both normal and emergency sources.Voltage differential sensing for single-phase loss detectionOver 30 standard accessories built in.RS 422/485 Communications Port.Windows based SCADA package available