1. A new hierarchical approach for modeling protection systems in EMT-type software
Henry Gras (Montreal Polytechnique, Canada)
Jean Mahseredjian (Montreal Polytechnique, Canada)
Emmanuel Rutovic (Powersys, Canada)
Ulas Karaagac (Montreal Polytechnique, Canada)
Aboutaleb Haddadi (Montreal Polytechnique, Canada)
Omar Saad (Montreal Polytechnique, Canada)
Ilhan Kocar (Montreal Polytechnique, Canada)
IPST, June 2017, Seoul, Republic of Korea

2. Introduction 1. Simulation software environment
Accurate simulation of non-linearity (transformers, arresters, power-electronics)
Protection devices inputs very similar to the ones on field.
2. Detailed models and open-architecture
Protection functions built with control-block diagrams which allow to understand the behavior.
Possibility to test new architectures

3. Content 1. General Architecture
Modelling challenges of protection systems in EMT-type software
Object-Oriented architecture.
2. Simulation examples and performance
Transformer energization
Statistical studies
3. Relay settings and protection scheme
Distance relay reaching determination
Power Swing and Out-Of-Step relay setting
4. Multi-Time-Step Implementation
Simulating relays at a time-step fitting there sampling frequency.

4. 1. General Architecture Challenges
Open architecture => large number of control devices
Reconfigurable to reproduce difference protection strategies, ex: different voltage polarization calculation methods for distance elements.
Simulation speed

5. 1. General Architecture Solutions
Black-box with DLLS:
- Pros: fast to simulate
Low memory usage
- Cons: Debugging is very complex
Built as one object:
- Pros: Low memory usage when several relays in the same design
- Cons: Non-configurable
Built with several macro-objects
Reconfigurable

6. 1. General Architecture Solutions

7. 1. General Architecture Solutions
1 relay
4 identical relays
4 relays of different manufacturers
Number of devices
Number of instances
9612
1694
Number of devices
Number of instances
35570
1748
Number of devices
Number of instances
37430
3421

8. 1. General Architecture Solutions
List of protection functions/devices modelled:
Distances (ANSI 21P, 21G)
Overcurrent (ANSI 50-51P, 50-51G, 50-51N, 50_2-51_2, 46)
Directional (ANSI 67P, 67G, 67N, 67_2)
Power Swing/Out-Of-Step (ANSI 68-78)
Loss-Of-Field (ANSI 40)
Under/Over Voltage (ANSI 27, 59, 59N, 59_2)
Frequency (ANSI 81O, 81U and 81R)
Fuse (current limiting, expulsion)
Thermal elements (Transformers, conductors)

9. 2. Simulation examples and performance Differential protection setting

10. 2. Simulation examples and performance Differential protection setting
With statistical studies: individual and common harmonic blocking settings are determined.

11. 3. Relay settings and protection scheme Impact of wind park integration on distance relay reach.
Zones 1 and 2, line distance protection Relay1 impedance trajectory locus, comparison of SMEQ and WP models.
Benchmark 5

12. 3. Relay settings and protection scheme Impact of wind park integration on distance relay reach.
According to how the wind-park is modelled, the reaching varies from 112.8% for a synchronous-machine equivalent model to 121% for a detailed wind-park model.
Benchmark 5

13. 3. Relay settings and protection scheme Impact of WP integration on power swing.
R-X diagram: comparison of worst stable swings, with WP and SMEQ models.
Benchmark 5

14. 4. Relay settings and protection scheme Impact of WP integration on power swing.
The circuit is simulated at 50µs and the relays sampling frequency is 20 samples per cycle. Therefore, relays can be simulated at 400µs without any loss of precisions.
The gain is substantial (3.2 times)
Simulation
CPU time (s)
Single-time-step
129
Multi-time-step 40

15. Conclusion
New modelling approach for protection systems in EMT-type software.
Built with block-diagrams with object oriented approach.
Composed of several macro-functions, reconfigurable according to user settings.
Engineering tools developed for specifics studies:
Transformer differential relay setting against energization
Distance relay reaching determination
Power Swing and Out-Of-Step protection setting
Possibility to improve computational performance by using multi-time step mesh.

16. Questions?