Page 19 of 190 Report No.: 6068396.50 TRF No. G99/1-4_V1.0 G99/1 Clause Requirement - Test Result - Remark Verdict 9.4.3 Harmonic Emissions P 9.4.3.1 Harmonic currents produced within the Generator’s system and modification of the harmonic impedance caused by the addition of the Generator’s installation may cause excessive harmonic voltage distortion in the Distribution Network. The Generator’s Installation must be designed and operated to comply with the planning criteria for harmonic voltage distortion as specified in EREC G5.
EREC G5, like all planning standards referenced in this recommendation, is applicable at the time of connection of additional equipment to a Generator’s Installation. P 9.4.3.2 For Power Generating Modules of up to 17 kW per phase or 50 kW three phase harmonic measurements as required by BS EN 61000-3-12 shall be made and recorded in the test declaration form A2-1 or form A2-3 as applicable for the Power Generating Module. The DNO will use these declared figures to calculate the required maximum supply impedance required for the connection to comply with BS EN 61000-3-12 and will use this data in their design of the connection for the Power Generating Module.
This standard requires a minimum ratio between source fault level and the size of the Power Generating Module, and connections in some cases may require the installation of a transformer between 2 and 4 times the rating of the Power Generating Module in order to accept the connection to a DNO’s Distribution Network. Detailed testing requirements are described in Annex A.7 P 9.4.3.3 Where the Power Generating Module is connected via a long cable circuit the likelihood of a resonant condition is greatly increased, especially at 132 kV. This arises from the reaction of the transformer inductance with the cable capacitance.
Resonance is likely in the low multiples of the fundamental frequency (8th-11th harmonic). The resonant frequency is also a function of the Total System fault level. If there is the possibility that this can change significantly eg by the connection of another Power Generating Module then a full harmonic study should be carried out. N/A 9.4.4 Voltage imbalance P