Grid code requirements and advanced power electronics solutions [Part 2/8: Grid code compliance (GCC)]

After the introduction of grid codes, this second article will discuss grid code compliance.

Where a grid code is in force, proof of compliance of the facility is required by the local TSO or DSO. Grid code compliance (GCC for short) includes the tasks related to assessment, verification and certification of the technical performance capabilities of different facilities as required in grid codes and similar documents. Similar documents could be laws dealing with power purchase agreements or conditions related to grid connection. Testing, simulation and evaluation of any impact of the facility in the electric power system can be also part of GCC.

Grid code compliance procedures in projects usually include:

• GCC studies and assessments (during the planning and execution phases).
• GCC tests (during commissioning).
• GCC monitoring (during commercial operation).

Grid code compliance verification

To avoid misinterpretations of grid code requirements, a grid code should be complemented by a good compliance verification plan, specifying clearly how each requirement must be validated to be able to obtain a certification. This is especially important when dealing with large projects. Grid code compliance verification has two main objectives:

• Facility owners must prove compliance to the grid code to the relevant system operator.
• System operators must assess the compliance to ensure that the facility does not adversely affect the secure operation of the electric power system.

GCC verification can be done by testing and simulation or by certification. The procedures for providing the proof of compliance differ from country to country, and may include manufacturer declarations, facility owner declarations, manufacturer unit test, facility test, and studies/models of static and/or dynamic behaviour. 

GCC verification by certification

It is possible to provide GCC verification of a facility via certificates issued by accredited certification bodies. These certifications are proof of compliance for specific capabilities and they are usually accepted in many countries.

GCC verification by certification can be given for a component, for equipment, for a certain type of devices (usually generators) or for the whole project via a project certificate.

GCC verification by testing

Tests can be performed on-site or off-site, via factory, laboratory or test bench. Testing is carried out for two main reasons:

• Performance compliance: To test compliance to contractual requirements and grid codes. These criteria point out specific levels to be met. Therefore, tests may be designed with binary pass/fail objectives.
• Model validation: Many system operators require dynamic models to be used in stability analysis for operation and planning purposes. Tests may be performed to tune and verify simulation models to closely match the performance of actual equipment.

The advantage of doing verification by testing is that it is representative of real equipment behaviour. The disadvantages are that typically it has high costs and it can have effects on the electric power system.

GCC verification by simulation

Most grid codes require electrical equipment manufacturers to provide technical data (from the device and associated control system) to the system operator. Depending on the requirements of a certain project, several types of simulation studies and calculations may be required by the system operator for the equipment involved. On-site tests are typically required to confirm the performance of the electrical equipment and to assist in the validation of the model.

The advantages of doing verification by simulation are that costs are low and is has no effects on the electric power system. The disadvantage is that simulations still need some form of validation.

International standards and grid codes

In the development and implementation of grid codes, other applicable technical and legal frameworks concerning electric power systems must be considered. The most relevant frameworks are the regulations set by energy policies and the technical requirements set by national and international standards.

Due to the varied scope, purpose and content of individual standards, grid codes and standards relate to each other in different ways:

• International standards can be used as a reference when writing a grid code and modified according to the specific needs of a country.
• International standards which govern the connection of generators can in some cases be used in place of a grid code.
• Standards can be referred from within the grid code. For example, grid codes often specify power quality requirements by referring to the relevant standards.

The next article of this series will discuss the Smart Grid and grid codes.

If you would like to receive any of my publications on the topic or to explore how #PowerElectronics solutions can help your installation to achieve grid code compliance, feel free to reach me at [email protected]. 

You are also welcome to join my running series of weekly #FreeWebinars for Asia-Pacific region on cutting edge #PowerElectronics solutions and their applications.

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About the author:

Pedro Esteban is a versatile, multicultural and highly accomplished marketing, communications, sales and business development leader who holds since 2002 a broad global experience in sustainable energy transition including renewable energy, energy efficiency and energy storage. Author of over a hundred technical publications, he delivers numerous presentations each year at major international trade shows and conferences. He has been a leading expert at several management positions at General Electric, Alstom Grid and Areva T&D, and he is currently working at Merus Power Plc.