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G59/3-2 Has arrived

The new G59/3-2 Engineering Regulations are now in place, there is a grace period of 18 Months from the launch Date of Sept 1st 2013, but you must be ready for these changes as the DNO have the right to enforce them right now.
 
In fact we have already done on site Witness Tests where the Witness has requested us to use the parameters and guidelines from the new G59/3-2 Engineering Regulations.
 
It is considered that the revised EREC G59/3-2 addresses comprehensively a massive range of issues. The most significant changes to the G59/2-1 document have occurred in:
 
Section 6, concerning the Connection Application process – this has made it clearer as to the requirements for consent, protection, commissioning tests and witness testing that are applicable for each Generating Unit size;
 
Section 7, which has been significantly extended to include provisions relating to the balancing of generation at the LV level and to make allowance for the introduction of Voltage Management Units
 
Section 9, where a new section of performance requirements for Type Tested Generating Units has been inserted, to align with EREC G83/2, and additional provisions relating to flicker;
 
Section 10, to reflect the change in nominal LV voltage to 230V throughout, this section also shows the alteration of the parameters for both over and under voltage settings.
 
Section 12, to align the Testing and Commissioning requirements with those proposed in EREC G83/2.
 
Section 13, This area is concerned with system stability and the best way that this stability can be achieved with consent from the DNO concerned.
 
The above changes have been clearly addressed through a variety of focused changes to the G59/2-1 document. In some areas significant redrafting has taken place to simplify and clarify the connection process, for the benefit of all users. In other areas the changes required specific technical modifications, and these appear to have been handled adequately.
 
The revised version of G59/3-2 represents a significant improvement on the previous version in terms of its compatibility with the other relevant Engineering Recommendations, and the alignment work that has been undertaken will serve electricity sector stakeholders well.
 
In general the recommendations within G59/2-1 have been transferred into G59/3-2, although there have been significant changes to the details of the interface protection and new type testing forms. A detailed mapping analysis on a paragraph basis was provided by the working group (WG) and so is not given in this report. The main points, however, are summarised below.

Phase balancing at LV
 
The revised document includes two new sections, 7.5 & 7.6 which address voltage unbalance due to single phase and split phase generating units. It was commented in the Report to the Authority that the requirements of G59/2-1 on single phase units were considered too onerous by both DNOs and Installers, as the DNO was required to carry out a study prior to connecting any single phase units >16A. The revised document now allows the possibility that multiple single phase devices may be connected so long as the installation ensures a maximum phase imbalance of 16A across any two phases. This condition adds a certain amount of complexity for installers, however two worked examples have been given, and the Consultants are satisfied that this should be sufficient guidance. It is also observed that this relaxation should not result in increased phase imbalance on the LV network, as the permitted imbalance is no greater that that allowed under G83 connections.
 
Harmonics
 
The Type Test for Harmonic Emissions has been revised such that harmonic emission tests according to product standard BS EN 61000-3-12 (for devices <75A) will no longer be sufficient to connect in areas where the grid is weak. Harmonic compliance is now subject to a minimum ratio between source fault level and the size of the generation unit. G59/3-2 now states that connections in some cases may require the installation of an oversized transformer in order to accept the connection.
 
The link between fixed current emission limits and the varying source fault levels across the network is understood to be a key feature of the revised G5 which is currently at draft stage. It is important that G5 and G59 are aligned, and so this change in approach in G59/3-2 is considered to be an improvement on G59/2.
 
DC Injection
 
Following the revision to EREC G83, the DC injection limits in G59/3-2 have been revised to 0.25% of the AC current rating per phase for all generating units. This percentage limit moves towards the example of the European standards; however European limits at present are between 0.5% and 1%. It is noted in the text that DC injection is an area currently under investigation and the 0.25% limit is imposed until the investigation is concluded.
 
Note : This investigation has now been going on for Two Years, but they will come to a conclusion soon and this is why we pay a lot of attention to DC injection and the problems it causes during our training courses.
 
Protection
 
The interface protection settings in G59/3-2 have been altered to bring G59/3-2 in line with the G83/2 protection settings for LV generators. Although a significant change, this has been well communicated to the industry and appears to be widely supported.
 
Both G83/2 and G59/3-2 voltage settings are now defined from a nominal voltage of 230V, with over-voltage settings of +14% and +19%. This represents a nominal change from the G59/2-1 settings which were based on a user selectable nominal voltage of 230-240V.
 
It is noted that these voltage excursions are wider than those permitted in the ESQCR and this is justified by the typical voltage drop within a customer's installation. The G59/3-2 Report to the authority makes clear that it remains the DNO's responsibility to ensure the system voltage does not exceed statutory limits. It is noted that the HSE do not raise any specific concerns about these settings in their response.
 
Reconnection times have been standardised across G59 and G83 to 20 seconds, this area will require almost all of the 18 Month grace period to become active and achievable.
 
Note: On all our engineer testing courses we will be using both G59/2-1 and G59/3-2 parameters.
 
Testing and Commissioning
 
The content of this section has been revised to group the requirements which are common to all Generating Units, regardless of size or type tested status. There are no material changes to the commissioning requirements, except to clarify circumstances when Witness testing by the DNO will be required.
 
For non-type tested Generating Units, stability tests, like those in the type testing process, have been added to the on-site commissioning process.
 
Note: I have read the new regulations several times and I'm of the opinion that it will be much easier to put in a G59/3-2 Relay Control Panel rather than try and get the self certified inverters through testing.
 
With G59/3-2 now being implemented by the DNO's, we have decided to run a one day training course.
 
If this is something of interest to you please get in touch to book your place. Dates available to suit you ... for £349 + VAT per person G59/3-2 Training Day
 
Email This email address is being protected from spambots. You need JavaScript enabled to view it. to book your place.

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