Page 18 - Industrial Technology October/ November 2020 issue

New harmony: the G5-5

harmonic recommendations

demand attention

The new G5-5 recommendations on harmonic disturbance are a significant
change to the previous G5-4. System integrators and end users must take
note to ensure compliance and variable speed drive manufacturers will also

need to assist by making their product data available. Wayne Turtill, Product
Manager for Variable Speed Drives, Servos and Low Voltage Switchgear at
Mitsubishi Electric UK, explains the impact of G5-5

ith the exception of the lightbulb, virtually all The proliferation of additional connections such as small-
equipment that doesn’t draw current in a linear scale power generation plants, has increased distortion on the
way will create harmonics. This category includes network and as a result the good practices recommended in the
Wvariable speed drives. Harmonic disturbance Electromagnetic Compatibility Regulations 2016 legislation
modifies the current and voltage waveforms and can cause issues required an update.
from the disruption of electronic controllers to the overheating of Already in effect, is the latest G5-5 iteration, which
switchgear. In the most extreme cases, harmonic disturbance can supports the updated good practices. Along with Mitsubishi
also result in the complete failure of connected equipment. Electric’s system service partner, PQM, the two organisations
represented drive and control equipment manufacturers on
More stringent harmonic regulation behalf of GAMBICA, the UK’s control and automation trade
The reach of harmonic disruption can even extend past a association, in the development of G5-5 with the Energy
company’s own location to those who share the power grid, such Network Association.
as sites in proximity using the same common voltage supply G5-5 defines the roles and responsibilities of all parties
(point of common coupling – PCC). For this reason, the Energy relating to harmonic disturbance levels, including network
Network Association (ENA), the industry body that represents the operators as well as network users. The network operator is
electricity network in the UK and Ireland, created the Engineering responsible for coordinating and setting the disturbance levels on
Recommendation (EREC) G5-5, which provides the maximum its network and the user’s responsibility is to comply with the
individual and total harmonic voltage distortion levels applicable conditions.
to UK distribution networks. The levels guide harmonic Crucially it is the network operator’s right to enforce the levels
assessments and set limits for the connection of non-linear / detailed in G5-5 and ultimately this means that the network
resonant plant and equipment. operator can withdraw electrical supply if G5-5 isn’t met.

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