Increasing demand for renewable energy, along with the requirement for a stable grid supply, is driving major changes within the power industry, with G59 and G83 regulations at the forefront of some of those changes. Deep Sea Electronics’ John Ruddock reports
Increasing demand for renewable energy, along with the requirement for a stable grid supply, is driving major changes within the power industry, with G59 and G83 regulations at the forefront of some of those changes.
The EU and surrounding countries have set ambitious targets to reduce greenhouse gas emissions by as much as 80-95% by 2050, with equally ambitious nearer-term targets for 2030. In order to meet these tough emissions targets, governments are busy securing initiatives to increase power from renewable energy sources, which, until recently, have formed a very small percentage of the total power produced.
Renewables, by their very nature, are much more variable as they depend on weather or climatic conditions which change, so looking to the future and our higher dependence on renewable energy has led to a review of grid protocols.
Supporting the European agenda for climate and energy, the European Network of Transmission System Operators for Electricity (ENTSO-E) has developed a series of network codes that are mandatory for all EU states.
The purpose of this article is to outline the key issues facing Europe’s power system today and the path it is taking to addressing future challenges. Part of this includes the Requirement for Generators Network Code (RfG) legislation, which covers protocols for grid connected generators across the 41 transmission system operators (TSOs) it represents, covering 34 countries including Great Britain. Now each country has the task of interpreting the requirements of the legislation and assessing how their energy models can best be adapted.
With governments across and beyond the borders of Europe committed to finding greener alternatives for generating power than burning fossil fuels, the number of inverter connected appliances feeding power into the grid from sources such as solar and wind installations etc, is growing daily. Governments are actively encouraging private energy producers to supply the network in increasing numbers and they form a valuable and growing energy resource.At present, all connected applications in Great Britain are governed by G59 or G83 regulations but these are due to be replaced with G99 or G98, which incorporate the new protocols from the RfG. This will provide a much more secure and safe framework for modern energy technologies when connecting to the grid, while at the same time maintaining the robustness of the network.
As equipment differs across borders, so the need for different guidelines has evolved. Each country has its own regulations covering grid protocols specific to their operations, but these must all be updated to encompass the new network codes over the next few years.
In the shorter term, G83 and G59 are under constant review and changes are being developed to maintain the stability of the grid in the face of the challenges posed by the growth in renewable generation.
There are many applications that were intentionally designed as stand alone systems and therefore had no requirement for G59 compliance. These are generally smaller installations primarily required to generate power for own consumption, but an increasing number are incentivised to supply surplus power back to the grid as a way of off-setting investment costs and to support growing energy demands. These applications have had to fit mains protections retrospectively in order to comply with G59. Installations that have chosen to be part of the STOR initiative offering emergency reserves on an ‘as and when called for’ basis, are also required to comply.
There are several ways in which connected applications are able to comply with the new regulations: through an independent mains decoupling device or through built in features within the inverter.
However it is done, the application will be required to disconnect from the grid in the event of a grid failure to prevent ‘islanding’ but at the same time preventing ‘nuisance’ disconnections during temporary and/or fleeting power disturbances and other grid events not caused by islanding events.
In effect the windows have been broadened to prevent applications from being ‘thrown off’ the network and putting all the burden on the remaining producers, while still operating within recommended guidelines.
Powerful independent devices such as DSE’s P100 mains decoupling relay can offer many benefits to these grid connected applications, especially when faced with the impending changes outlined above.
Used to detect grid failures when in parallel with another supply, the microprocessor-based technology of the P100 has USB connectivity which allows changes to parameters and product upgrades, so the application can keep pace with emerging new requirements and can be configured to comply with different global regulations.
Also built into the product is the ability to record up to 250 events providing useful trend analysis, and a high number of sophisticated protections such as two-stage under and over frequency protection, five-stage under and over voltage protection, 10 second rolling average over voltage protection, voltage asymmetry and vector shift protection, three separate R.O.C.O.F protections, incorrect phase sequence protection plus a host of other powerful features. The product also has built-in security to prevent unauthorised or accidental configuration changes post commissioning.
So for installations having independent devices such as DSE’s P100, it is easy to adapt which makes it a cost-effective solution when regulations change and benefits those companies wanting to standardise equipment across multiple national TSOs.
Changes within the new RfG legislation, which will be covered in the G98/99 regulations, also take into account the need for intelligent active and reactive power control modes.
The fault ride through (FRT) immunity requirement is intended to provide greater grid stability by reducing unnecessary trips during short power dips caused by network faults. DSE’s 86xx MKII generator controls have frequency dependant kW control and voltage dependant kVar control built in for exactly this purpose.
When changes of the magnitude associated with G98/99 are announced, it can be quite tough to understand what the requirements mean in real terms to the way organisations have to adjust their operations. Some of the difficulties can lie in the inability of equipment to adapt to new criteria.
Recognising the differences between different events on the grid, where the outcome is required to automatically disconnect or stay connected, now requires a much higher level of capability, so intelligent products that help with compliance can provide a very welcome and valuable solution when integrated within appropriate power systems.