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G99 Witness Testing & Commissioning 

Pannell & Partners undertakes G99 testing & pre-commissioning for system approval across the whole of the UK. Following on from G99 acceptance, we can offer Frequency Response Testing.  
 
Periodic Testing - a requirement of ENA's G99 Document. Please contact us to programme in a suitable schedule for your "Loss-of-Mains" protection system. 
 
LATEST - We are able to undertake ALoMCP works to update your system interface protection Loss-of-Mains to the latest DNO requirements. 
 
G99 tests are applicable to battery energy storage (BESS), PV (photovoltaic) solar parks, wind turbine installations, CHP (combined heat and power) installations including Anaerobic Digester installations and rotating machine embedded generation. 
 
Our extensive experience in G99 witness testing, from battery energy storage, commercial rooftop solar PV to the UK's largest ground mount solar PV parks, hydroelectric, CHP, wind turbine and short term parallel generators means that you can have confidence in successful G99 witness testing completion. 
 
We strongly recommend contacting us at the same time as the DNO when booking a G99 witness test, so we may converse directly with the DNO to arrange mutually conducive dates. This prevents the embarrassing situation of not being able to find a G99 tester for the witness test if it is left too close to the commissioning date. 
 
Our many clients have also recognised the benefits of arranging a pre-commissioning G99 test prior to the scheduled witness test. Any problems found can be remedied before the DNO is due to attend site, if arranged a day or two (or longer) before the final witness test. This saves missing deadlines, losing money and requesting repeat visits from the DNO - a problem with their very busy schedules. 
 
Feedback from DNO engineers has shown that they are very impressed when clients have taken this initiative to prepare their sites properly before the witness test - it gives them confidence in the system. 
 

Full guidance throughout 

We can guide you through the connection application process with the DNO, having extensive experience in LV, 11kV, 33kV & 132kV connected generation systems and can offer advice and direction for correct application. 

G99 Relay & Control Panels 

We are able to provide complete G99 protection solutions including design, manufacture and installation of G99 relay control panels whether bespoke or “off the shelf” to any specification for all renewable / dual-energy embedded generation applications. 

Tailored result sheets 

We issue tailored result sheets signed by our highly skilled test engineers and the DNO protection engineer representative which consist of all parameters required by the DNO according to Engineering Recommendation G99. These sheets represent the recordable test data required by the DNO to enable connection and OFGEM approval. 

Pre-commissioning service 

We also offer a pre-commissioning service where we can assess the correct operation of the G99 control interface with the dual energy system prior to the DNO witness test visit. 
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