1. RfG Implementation Fault Ride Through
Antony Johnson
National Grid – Network Capability

2. Summary
High level voltage against time curves prepared last year and presented to the GC0048 Workgroup
A number of substantive comments received which resulted in further review
The high level voltage against time curves for Type B – D Synchronous Power Generating Modules and Power Park Modules are covered in this presentation
These suggested voltage against curves need to be assessed against the fast fault current injection performance requirements.
Studies have been started on fast fault current injection and are to be covered via a separate presentation.
There is close relationship between fast fault current injection, the fault ride through voltage against time curves and banding.

3. RfG - Fault Ride Through Requirements – Voltage Against Time Profile – Figure 3
Describe process as per slide

4. Type D Synchronous Power Generating Modules Connected ≥ 110kV

5. GB Type D Voltage Against Time Curve
Type D Synchronous Power Generating Modules connected at ≥110kV
GB Type D Voltage Against Time Curve
Connection Point Voltage (pu)
NOT TO SCALE
1.0
0.9
0.5
Describe process as per slide
0.25
0.14
0.45
1.5
Time (s)

6. Type C and D Synchronous Power Generating Modules Connected <110kV

7. Suggested Voltage Against Time Profile – Type C and D
Type C and D Synchronous Power Generating Modules Connected <110kV
Suggested Voltage Against Time Profile – Type C and D
Connection Point Voltage (pu)
NOT TO SCALE
1.0
0.9
0.7
Describe process as per slide
0.10
0.14
0.45
1.5
Time (s)

8. Type B Synchronous Power Generating Modules Connected <110kV

9. GB Voltage Against Time Profile – Type B
Type B Synchronous Power Generating Modules Connected <110kV
GB Voltage Against Time Profile – Type B
Connection Point Voltage (pu)
NOT TO SCALE
1.0
0.9
0.7
Describe process as per slide
0.30
0.14
0.45
1.5
Time (s)

10. Type D Power Park Modules connected ≥110kV

11. GB Voltage Against Time Profile – Type D
Type D Power Park Modules connected ≥110kV
GB Voltage Against Time Profile – Type D
Connection Point Voltage (pu)
NOT TO SCALE
1.0
0.85
Describe process as per slide
0.14
2.2
Time (s)

12. Type B, C and D Power Park Modules connected <110kV

13. GB Voltage Against Time Profile - Type B, C and D
Type B, C and D Power Park Modules connected <110kV
GB Voltage Against Time Profile - Type B, C and D
Connection Point Voltage (pu)
NOT TO SCALE
1.0
0.85
Describe process as per slide
0.10
0.14
2.2
Time (s)

14. Example of PPM connected below 132kV
Voltage - time ride through requirements. Example for a 132kV fault with a two transformer grid substation feeding generation connected at 33kV
1st 132kV end clears at 100ms, second 132kV end clears at 130ms, 33kV DOC operation clears at 440ms. Tap changer operation starts at 60 seconds and restores voltage to target at 110 seconds. Vertical line at 180 seconds to at least meet statutory min voltage level for the connection in question typically 0.94 pu but without a defined end point.

15. Issues
Different voltage against time requirements between Synchronous Type B and Synchronous Type C and D connected below 110kV
Retained voltage for Type B, C and D Power Park Modules and Type C and D Synchronous Plant set to 0.1pu
Dependency on Banding is also related to Fast Fault Current Injection (FFCI) and fault ride through capability
Need to ensure Embedded Generation is not lost for a Transmission System fault – particularly if the post fault voltage falls within the 0.85 – 0.9 region prior to tap changers operating
A CBA will need to be undertaken to establish the volumes of Embedded Generation which could be lost for a Transmission System fault.
Transition between fault ride through mode and statutory voltage limits needs to be understood