05 ptcc automation overview
- 1. PTCC Automation Overview For Automatic Circuit Reclosers and Load Break Switches
- 2. Automation Features Automatic Protection Group Selection Generator Control Automatic Change-over Loop Automation
- 3. Automatic Protection Group Selection Automatic Protection Group Selection (APGS) allows the appropriate Protection Group to be selected automatically without the need for operator intervention. It works by automatically changing between Protection Groups depending on the direction of power flow. Source Load Forward Power Flow Protection Group A Reverse Power Flow Protection Group B
- 4. Where is APGS used? Sometimes a circuit breaker is used at a location in a supply network where the power flow can be in either direction depending on the configuration of the rest of the network. One example of this is a network tie point where the operator may have to select a different group of protection settings to compensate for a change in power flow when changing the network configuration. Emergency switching configurations may require more than one pair of Protection Groups. Fdr 1 Fdr 2
- 5. The Selection Rules Each pair of Protection Groups (A&B) (C&D) (E&F) (G&H) (I&J), contains one Primary and one Alternate Protection Group. The number of APGS pairs depends on how many Protection Groups have been configured. When the power flow is in the positive direction (source to load) Primary Protection Group A,C,E,G or I is used. When the power flow is negative, Alternate Protection Group B,D,F,H or J is used. For APGS to generate a change from Primary to Alternate Protection Group, the power flow must be >50kW in the negative direction for longer than the set period. To Revert to Primary Protection group the power must be >50kW in the positive direction for longer than the set period. Protection Groups A B C D E F G H I J Pri Alt A B C D E F G H I J
- 7. Generator Control Operation The Generator Control option can disconnect the normal source of supply when it fails and automatically start a standby generator to supply the load. When the normal source of supply is restored, the generator is automatically shut down and the supply reconnected.
- 8. Generator start-up Generator IOEX ACR Source & Load side LIVE Source & Load side DEAD Switch OPEN Generator START Request on Generator RUNNING CB
- 9. Generator IOEX ACR Power restoration Generator RUNNING Source & Load side LIVE Generator START Request off Generator OFF Switch CLOSED CB
- 10. Summary of Operation Starts generator Senses loss of source side supply. Isolates normal supply line. Operates generator via IOEX output. Keeps generator running till power supply is restored. Reverts to normal supply Senses restoration of normal supply. Turns generator off. Reconnect to normal supply. Safety Closing of switch is disabled when generator supply is active.
- 11. Generator Control settings HV Dead Time Amount of time source side bushings are “dead” before any action performed by Generator Control. Also used to detect when the generator has stopped. Range: 1 to 600 sec HV Live Time Amount of time source side bushings are “live” before any action performed by Generator Control. Also used to detect when a generator is running. Range: 1 to 600 sec Control State: What Generator Control is doing.
- 14. Automatic Change-Over The Automatic-Changeover (ACO) scheme enables supply from either of two sources in support of a single load. This scheme is normally used in support of a critical load such as a hospital to ensure that alternate supply is always available in the event of power failure.
- 15. Automatic Change-over Operation Preferred Alternative
- 16. Automatic Restoration Supply may be automatically restored using either of the following principles depending on the compatibility of the supply at each feeder. Break Before Make In this mode the Master device will instruct the Slave device to open and then wait until the Master switch’s load side bushings are confirmed as dead before closing itself and connecting to the load. This will cause a short interruption of supply to the load during the confirmation period. Make Before Break In this mode the Master will close onto an energised load and then instruct the Slave to open after confirming the presence of HV for a specified period, without interruption of supply to the load.
- 17. Make Before Break Restoration Preferred Alternative
- 18. Break Before Make Restoration Preferred Alternative
- 19. Automatic Change-over Communications Preferred Alternative Control Centre DNP3 ACO
- 20. Auto-Changeover – Important Points Auto-Changeover cannot be made available if other automation features are available. Auto-Changeover can only be used when DNP3 or another suitable protocol is available. Make Before Break can only be used for restoration when the preferred and alternative supply are compatible. When the Auto-Changeover scheme is installed the SLAVE device must be installed, configured and checked first before the MASTER device is configured.
- 21. Loop Automation
- 22. Loop Automation – An Overview Loop Automation is a Distributed System Automation (DSA) scheme that will restore supply to fault free sections of a network if they have been disconnected because of a fault in another section of the network. Loop Automation can also restore the normal network configuration automatically when the faulted section is repaired. The distributed intelligence embedded in the reclosers operates the scheme without communications or operator intervention by using the built-in voltage detection of Nu-Lec reclosers. No additional equipment is required.
- 23. Loop Automation Operating Principal Loop Automation reconfigures a network to restore supply to fault free sections of a network. It achieves this through a number of steps: Isolate faulted section. Reconfigure network so that unfaulted sections receive supply. Automatically restore the normal configuration when the fault is removed.
- 24. Types of Recloser Loop Automation defines 3 “types” of reclosers. Feeder recloser – Recloser closest to the substation. Tie recloser – Normally Open point where two feeders meet. Mid-point recloser – Reclosers anywhere on network between Feeder and Tie reclosers. Tie Recloser Feeder Reclosers Mid-point Reclosers
- 25. Loop Automation re-configuration rules Rule A: The Feeder Recloser trips when it loses supply. Rule B: Mid-point Reclosers changes to “B” Protection group and activates single shot mode when the source supply is lost. Rule C: Tie Recloser closes when supply is lost on one side only. i.e. Other supply is available. Feeder Reclosers Mid-point Reclosers Tie Recloser
- 26. Loop Automation re-configuration - Example Rule B: Mid-point Reclosers changes to “B” Protection group and activates single shot mode when the source supply is lost. Rule C: Tie Recloser closes when supply is lost on one side only. i.e. Other supply is available Feeder Reclosers Mid-point Reclosers Tie Recloser A Prot GroupB Prot Group Single Shot
- 27. Loop Automation Restoration Rules Rule D: The Feeder Recloser closes when source supply is restored and it was tripped by LA, or When supply is restored on both sides. Rule E: Mid-point Reclosers closes when supply is restored to both sides. Rule F: Tie Recloser trips when power flow reduces by 50%, or Power flow direction reversal. Feeder Reclosers Mid-point Reclosers Tie Recloser B Prot Group Single Shot
- 28. Loop Automation restoration – Mid-Point Rule E: Mid-point Reclosers closes when supply is restored to both sides. Feeder Reclosers Mid-point Reclosers Tie Recloser B Prot Group Single Shot
- 29. Loop Automation restoration – Tie Rule F: Tie Recloser trips when power flow reduces by 50%, or Power flow direction reversal Feeder Reclosers Mid-point Reclosers Tie Recloser A Prot GroupB Prot Group Single Shot
- 30. Supply Auto-Changeover In addition to improving the quality of a supply in a network, Loop Automation can also be used to provide a secure supply to a critical load by implementing an Auto-Changeover (ACO) scheme.
- 31. Loop Automation as Supply Auto-Changeover Feeder Recloser Tie Recloser Rule C: Tie Recloser closes when supply is lost on one side only. i.e. Other supply is available Rule A: The Feeder Recloser trips when it loses supply.
- 32. Loop Automation as Supply Restoration Feeder Recloser Tie Recloser Rule D: The Feeder Recloser closes when source supply is restored and it was tripped by LA, or When supply is restored on both sides Rule F: Tie Recloser trips when power flow reduces by 50%, or Power flow direction reversal
- 33. Considerations when using Loop Automation in a Auto Change-over scheme Advantage No communications required between reclosers. Disadvantage Only Make before Break restoration is available.
- 34. Automation Overview A couple of points to note if you are considering using automation features: Loop Automation is a licensable feature and will only work with controllers which have their CAPM4/5 serial numbers embedded into the software. Loop Automation, Auto Changeover and Generator Control are mutually exclusive features.
Editor's Notes
- #5: Automatic Protection Group Selection is utilised by the Loop Automation function to change the active protection group during system reconfiguration. The setting range for the APGS time is 10 to 180 seconds. A minimum of 10 seconds is required for the CAPM to calculate the new protection group settings.
- #9: When a fault occurs and power is lost to a critical load, the switch with Generator Control enabled will start the generator. To do this the control system follows the following simplified steps: Detects loss of supply; After a preset time period (HV Dead Time), the controller trips the switchgear to isolate the normal source of supply; Enables an IOEX output to start the Generator; and Keeps the generator running until power is restored.
- #10: When the normal source of supply is restored the controller will turn the generator off and reconnect the critical load to the normal supply. The following steps are followed during restoration: Normal source must be Live for the duration of a preset time (HV live time); The Generator Start request IOEX output is turned off; and When the Generator is OFF, the switch is closed to reconnect the normal supply. Closing of the switch is disabled while the generator is ON.
- #11: Generator control allows a generator to be operated by an IOEX output in response to loss of supply, which is sensed by the line side bushings. After a preset time period (HV Dead Time) the CAPM will trip the ACR/LBS to isolate the load. When the ACR/LBS opens, the CAPM, via a set of IOEX contacts will turn the generator on. The generator will stay on until the supply is restored. When supply is restored to the system, and after the expiration of a preset time (HV Live Time) the generator is turned off and the CAPM will close the ACR/LBS to restore supply to the load. Closing is prevented when supplying the load via the generator. This is a safety feature to prevent closing onto unsynchronised supplies.
- #12: GenCtrl ON/GenCtrl OFF Generator Control: This field is used to turn on or off Generator Control. Factory default is OFF. HV Dead Time Line Supply Dead Time: Amount of time line side bushings are “dead” before any action performed by Generator Control. Also used to detect when a generator is stopped. Range: 1 to 600 sec Factory default is 5 sec. HV Live Time Line Supply Live Time: Amount of time line side bushings are “live” before any action performed by Generator Control. Also used to detect when a generator is running. Range: 1 to 600 sec Factory default is 5 sec. Control State: Shows what Generator Control is doing. Control State: GenCtrl OFFControl State: Switch ClosedControl State: Line Dead CheckControl State: Wait Switch OpenControl State: Wait Generator LiveControl State: Generator RunningControl State: Line Live CheckControl State: Wait Generator OffControl State: Wait Switch Closed
- #16: When the preferred supply is lost due to an upstream fault condition, the controller at the closed Master Device automatically trips the switch and then instructs the Slave Device to close. This sequence automatically connects the load to the alternative supply. When the Master Device controller detects that the fault condition has been cleared and the preferred supply source has been restored, it automatically restores supply back to the normal configuration.
- #20: The Auto-Changeover scheme uses radios or modems at both the Slave and Master to: Provide communications between devices, and Provide communications to a SCADA Master Station via DNP3 When the Auto-Changeover Master Device communicates with the Slave Device it uses a Nu-Lec ACO protocol format which is separate from any additional protocol used. This protocol wraps Auto-Changeover date in a packet with the recipient address. When transmitted, the Auto-Changeover partner controller recognises the packet and acts accordingly. If any communication parameters are to be altered on either Auto-Changeover or DNP3, Auto-Changeover on both the Master and Slave Devices should be turned OFF first.