1. IPS-SLR™ Static Line Rating Module and ElectraNet Use Case IPS-ENERGY™
© 2016 IPS GmbH

2. Overview Definition of Line Rating and Terminology
Influence of Topologycal Connectivity
Static Rating – Which types of equipments have impact?
Conductor Ratings
Impact of Protection
Calculated Static Rating Values
ElectraNet, Adelaide, Australia – approach
IPS-ENERGY Static Rating Implementation
Static Rating Data Model – Structure and Advantages
Interfacing
Conclusion

3. Static Rating – Definition and Terminology
IPS-ENERGY assumes following „vocabulary„ to be used
Thermal current limit (current carrying capacity / ampacity) is defined as the maximum amount of electrical current a conductor or device can carry before sustaining immediate or progressive deterioration.
A static thermal current is a current which causes that conductor, operating under presumed atmospheric conditions, designed for certain maximum continuous operating temperature and certain maximum operating sag, reaches one of either limits: the maximum conductor temperature or the maximum sag.
A dynamic thermal current is a current which causes that conductor, operating under real atmospheric conditions, designed for certain maximum continuous operating temperature and certain maximum operating sag, reaches one of either limits: the maximum conductor temperature or the maximum sag.
Current carrying capacity of a conductor is defined for a certain construction and implies certain ambient conditions and is usually provided by the manufacturer of the conductor. Current carrying capacity is therefore related to material and construction of the conductor at given ambient conditions.
The static line rating in the sense of IPS-ENERGY Static Line Rating Calculation represents the maximum amount of electrical current that the entire circuit where the overhead line is connected can carry before sustaining immediate or progressive deterioration
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4. Static Rating – Equipments taken into consideration – Part 1
The Line static rating values are calculated as a minimum of following three components:
Rating information related to line itself
Rating information calculated from line feeder (bay) secondary equipment (relay loadability)
Plant rating – rating calculated from primary equipment assets associated to circuit (all conducting equipment in the plant between line and the bus)
The list of conducting equipment considered for primary plant rating calculation includes (but not limited to) following equipment types
Bus
Circuit Breaker
Disconnector
Current Transformer
Wave Trap
Capacitor bank
Dropper
Fuse

5. Static Rating – Equipments taken into consideration – Part 2

6. How conductor ratings are modeled – ElectraNet approach
Define Table of Conductor Ratings per Conductor Types
Assign Conductor Type for each Primary Equipment (in Primary Plant)

7. How conductor ratings are modeled – Alternative approach
Create Conductor objects as assets and associate them to connectivity diagrams

8. The impact of protection – Part 1
Each customer has own „relay loadability” strategy – how to calculate the current limits sets by protection
ElectraNet takes into consideration relays with OC and Distance protection functions
For each used relay type (model) Calculation Studio formula is created that calculates current limit based on data got from actual relay settings

9. The impact of protection – Part 2
The formula is defined for each pattern and assigned to each relay asset that uses that pattern
The values taken as an input:
relay parameters from active setting
CT primary and secondary Amps
VT primary and secondary Voltages
The result of the formula is the current limit – based on the protection setting

10. Thermal limit of the Current Transformers – Part 1
The primary and the secondary thermal limits are CT nameplate data

11. Thermal limit of the Current Transformers – Part 2
The static rating calculation process is checking all cores and the rated primary and secondary current configuration on each cores in order to determine the minimum configured rating
The actual configuration might „reduce” the value of the thermal limit compared to nameplate thermal limit

12. The impact of secondary equipment’s current carrying capacity

13. Static Rating Templates – Temperature Bands
The static ratings depend on temperature
Predefined temperature intervals are configured where different rating values are assigned for each interval

14. Static Rating Templates – Line Rating Types
In typical configuration two rating types are used:
Normal or nominal rating (called also nameplate rating)
The short term rating (sometimes called emergency rating; also called a 15 minute rating) is the value where the operator has usually minutes to do something to reduce the load.
Additional rating types could be defined and used as well.
Victoria, Australia besides the above two ratings is using an additional rating type named load shedding rating (sometimes called 5 minutes rating).

15. Static Rating Templates – Rating Model in IPS-ENERGY

16. Static Rating Templates – Line Rating Model Example

17. Static Rating Calculation – Part 1

18. Static Rating Calculation – Part 2 (drill down)

19. Interfacing

21. Thank you very much for your attention
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