Validation of EMT Digital Twin Models for Dynamic Voltage Performance Assessment of 66 kV Offshore Transmission Network
Abstract
:1. Introduction
- Modified Droop Control: This strategy is common for standalone grids, where the parallel operation of voltage forming units is developed recently using the f/P (frequency/active power) and V/Q (voltage/reactive power) droop controls similar to the control in synchronous generators [7]. Few authors have named these droop control concepts as Virtual Synchronous Machines Without Inertia (VSCM0H) [8].
- Direct Voltage Control (DVC): DVC is a representation of the conventional current control approach towards a voltage control. DVC allows for the direct control of the AC converter voltage which in turn varies the current injected by the converter [9,10]. This approach provides continuous voltage control both in steady-state and dynamic scenarios.
2. Overview of the Digital Twin Model in RSCAD
- An aggregated representation of ∼700 MW installed capacity OWF is modelled with the following elements:
- –
- Wind Generation System
- –
- High Pass filter (HPF) with series reactor
- –
- OWF transformer
- HVAC cables
- External AC system
2.1. Aggregated OWF
2.1.1. Wind Generation System
2.1.2. High Pass Filter (HPF) with Series Reactor
2.1.3. OWF Transformer
2.2. HVAC Cables
2.3. External AC System
3. Control Structures
3.1. Implementation of DVC in RSCAD
3.1.1. Reactive Power Control
3.1.2. Active Power Control
3.1.3. Current Limitation
3.1.4. Voltage Limitation
4. Analysis of the Dynamic Performance of 66 kV Test System
4.1. Three-Phase Line to Ground Fault
4.1.1. Parameter Selection for Washout Filters
5. Overview of the Digital Twin Model in PowerFactory
- A simplified model of Full Scale Converter (FSC) based Type-4 WG system consisting of the following elements:
- –
- DC circuit
- –
- GSC
- HPF with series reactor
- OWF transformer
- HVAC cables
- External AC system
5.1. Simplified FSC Based WG System
5.1.1. DC Circuit
5.1.2. GSC
5.2. HPF with Series Reactor
5.3. OWF Transformer
5.4. HVAC Cables
5.5. External AC System
5.6. Control Structures
6. Comparison of Models in RSCAD and PowerFactory
6.1. Selection of Time Step in RSCAD and PowerFactory
6.2. Event Comparison in RSCAD and PowerFactory
7. Conclusions
Author Contributions
Funding
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Appendix A
Parameters | Description | Unit | Value |
---|---|---|---|
Static gain for slow global reactive power control | p.u. | 6.6 | |
Maximum/minimum reactive power | p.u. | 0.31 | |
Slow global reactive power control proportional gain | p.u. | 0.002 | |
Slow global reactive power control integral time constant | s | 15 | |
Fast local voltage control proportional gain | p.u. | 0.2 | |
x | Converter reactance | p.u. | 0.1 |
Washout filter proportional gain | p.u. | 0.05 | |
Washout filter time constant | s | 0.01 | |
Maximum q-axis converter control voltage |
Parameters | Description | Unit | Value |
---|---|---|---|
DC voltage control proportional gain | p.u. | 1 | |
DC voltage control integral time constant | p.u. | 0.1 | |
Proportional gain for direct frequency control | p.u. | 1 | |
First order delay for direct frequency control | s | 0.2 | |
Washout time constant for the voltage dependent active power reduction | s | 60 | |
Proportional gain for voltage dependent active power reduction | p.u. | 2 | |
First order delay for the voltage dependent active power reduction | s | 0.005 | |
x | Converter reactance | p.u. | 0.1 |
Washout filter proportional gain | p.u. | 0.05 | |
Washout filter time constant | s | 0.01 | |
Voltage measurement delay | s | 5 | |
Deadband for direct frequency control | Hz | 0.2 | |
Deadband for voltage dependent active power reduction | p.u. | 0.1 | |
Maximum d-axis converter control voltage |
Parameters | Description | Unit | Value |
---|---|---|---|
Gain for current limitation | p.u. | 1.2 |
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Parameters | RSCAD | PowerFactory |
---|---|---|
WG model | PMSG | Simplified (Constant power model) |
MSC control | Conventional current control | Not modelled |
GSC model | VSC with PWM | Controlled Voltage Source with no PWM |
Generated active power from WG | 6 MW | ∼700 MW |
Scaling factor at transformer | 116 (cf. Section. Section 2.1.3) | Not applicable |
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Ganesh, S.; Perilla, A.; Torres, J.R.; Palensky, P.; van der Meijden, M. Validation of EMT Digital Twin Models for Dynamic Voltage Performance Assessment of 66 kV Offshore Transmission Network. Appl. Sci. 2021, 11, 244. https://doi.org/10.3390/app11010244
Ganesh S, Perilla A, Torres JR, Palensky P, van der Meijden M. Validation of EMT Digital Twin Models for Dynamic Voltage Performance Assessment of 66 kV Offshore Transmission Network. Applied Sciences. 2021; 11(1):244. https://doi.org/10.3390/app11010244
Chicago/Turabian StyleGanesh, Saran, Arcadio Perilla, Jose Rueda Torres, Peter Palensky, and Mart van der Meijden. 2021. "Validation of EMT Digital Twin Models for Dynamic Voltage Performance Assessment of 66 kV Offshore Transmission Network" Applied Sciences 11, no. 1: 244. https://doi.org/10.3390/app11010244