GridCode Product Features
New rules and grid codes for the connection of generators to the grid are emerging worldwide. In every country or region, the operators responsible for the safety and reliability of the power system, have established different requirements for the connection of renewable generation systems to the electrical networks depending on the particularities of every power system. The term “Grid Code” is frequently used to refer to these rules and laws which define the technical requirements for third parties connected to public electricity systems. DIgSILENT has developed and released a analysis tool called “DIgSILENT GridCode v2.3”, in response to the need to verify if a wind farm, solar plant, or any other generator is compliant with the local Grid Code requirements.
Data Viewer and Phasor Viewer
The Data Viewer allows the user to read and check input files before performing any analysis. Input files can be obtained from measurements or simulations, containing different channels, sampling rates, etc. The Phasors Viewer is inspired by a classical relay viewer. It performs a spatial visualisation of calculated phasors from the input file at any instant of time (fundamental and sequence components, line and phase measurements).
New readable file formats (i.e. FAMOS©) are included in version 2.3 together with many improvements for debugging the user-defined format option: warning messages when a series is missing, etc. Extra tools are included to improve post-processing, speed up the analysis and manage files from different measurement equipment (File Editor, Resampler, Merger tools).
Power Quality Assessment
DIgSILENT GridCode v2.3 is improved for the assessment of power quality in distribution and transmission networks. The algorithms are compliant with the following IEC standards:
- IEC 61000-4-15: Electromagnetic compatibility (EMC) - Part 4-15: Testing and measurement techniques - Flickermeter - Functional and design specifications to assess flicker emission levels.
- IEC 61000-4-7: Electromagnetic compatibility (EMC) - Part 4-7: Testing and measurement techniques - General guide on harmonics and interharmonics measurements and instrumentation, for power supply systems and equipment connected thereto.
- Toolbox IEC 61400-21: Measurement and assessment of power quality characteristics of grid connected wind turbines. The toolbox incorporates the calculation of instantaneous flicker, flicker coefficients, flicker during switching operations, current harmonic emissions, interharmonic, higher frequency component emission levels and a special observation of the evolution in time of DFT components.
Check Grid Code Compliance
The most popular tool in DIgSILENT GridCode is the Compliance module. This module is used for the verification of the response of renewable or conventional power plants during and after external events or perturbations like voltage dips (LVRT), voltage swells (HVRT), active or reactive power steps, etc. The requirements are related to reactive current support (Ir/V), active and reactive power ramping and recovery, etc. The following country-specific requirements are supported: Australia, China, Denmark, Germany, South Africa, Spain, UK, and US.
The following European or International Regulatory Bodies and documents are included:
- European Network of Transmission System Operators (ENTSO-e): Network Code for Requirements for Grid Connection Applicable to all Generators
- International Electrotechnical Commission (IEC): IEC 61400-21 Ed. 2 Wind turbines – Part 21: Measurement and assessment of power quality characteristics of grid connected wind turbines
The new features in DIgSILENT GridCode v2.3 grid code assessment methods are:
- The UK NGC Grid Code, Issue 5 Revision 15, 3rd February 2016 (corrected 16th March 2016).
- Update of Prony Analysis (Australian GC).
- A new faster calculation function is implemented, called Prony Reduced, which includes a new reference step option and enhancements to the event selection window.
ON-LINE Compliance Monitoring System
There is a new trend towards verification of requirements at the point of interconnection by permanent monitoring. Often, the registered data are simply stored, never used or analysed or worse, they are kept in the monitoring device until overwritten by new ones.
DIgSILENT GridCode can now be integrated into existing monitoring systems to offer added value in post-processing the registered events automatically and report the compliance to the person in charge. Huge benefits can then be extracted for network operation and planning, not only in a point-to-point analysis but, as the results are stored in a database, important systemic and statistic results can be highlighted.
Access to results and reports are very easy via a web interface; Email alarms can be sent in case of no compliance or important event.
This module compares experimental results with simulation outputs, a crucial part in any model development and certification process. To check if simulation and test results are matching, different methods are included:
- International Electrothecnical Commission (IEC): IEC-61400-27-1 - Wind turbines – Part 27-1: Electrical simulation models– Wind turbines.
- Fördergesellschaft Windenergie und andere Erneuerbare Energien (FGW e.V.): TR4 Rev. 8 – Technical Guidelines for Power Generating Units - Part 4: Demands on Modelling and Validating Simulation Models of the Electrical Characteristics of Power Generating Units and Systems. Germany.
- Comité Técnico de Verificación de la Asociación Empresarial Eólica (AEE): PVVC Rev. 10 – Procedimientos de verificación, validación y certificación de los requisitos del P.O.12.3 sobre la respuesta de las instalaciones eólicas y fotovoltaicas ante huecos de tensión”. Spain.
- China Electric Power Research Institute (CEPRI): Internal procedure applied by the Wind Power Grid Interconnection Research and Evaluation Centre.
- Australian Energy Market Operator (AEMO): Generating system model guidelines Rev. 1. Australia.
- Update of the model validation method FGW TR4 Rev6, according to version dated 01.05.2013.