Realistic emission limits for distorting customer
installations are a crucial requirement for a reliable
operation of public distribution networks and an efficient
utilization of the existing hosting capacity for harmonic
emission. To manage harmonic levels in a power system,
the compatibility level has to be shared between all voltage
levels. The share of each voltage level is called global
contribution and is determined by the planning level of the
considered voltage level and the level of downstream
transfer of harmonic distortion from the upstream
network. Realistic values for the global contribution
require therefore reliable knowledge about the level of
downstream transfer between voltage levels. The
downstream transfer is quantified by the harmonic
transfer coefficient and due to lack of knowledge, usually
assumed to be one.
This paper presents a measurement-based evaluation of
the transfer coefficient for two EHV/HV transformers at
different substations. At each substation the inrush current
generated by switching another EHV/HV transformer at
primary side is used as dedicated upstream harmonic
source. The presented measurement results shall
contribute to the discussion about realistic transfer
coefficients for the calculation of global contributions.