BS EN 61869-6 is a safety standard on low-power instrument transformers.
BS EN 61869-6 is a product family standard and covers only additional general requirements for low-power instrument transformers (LPIT) used for a.c. applications having rated frequencies from 15 Hz to 100 Hz covering MV, HV, and EHV or used for d.c. applications. BS EN 61869-6 is based on IEC 61869-1:2007, in addition to the relevant product-specific standard.
BS EN 61869-6 defines the errors in the case of analogue or digital output. The other characteristics of the digital interface for instrument transformers are standardized in IEC 61869-9 as an application of the standards, the IEC 61850 series, which details layered substation communication architecture. BS EN 61869-6 considers additional requirements concerning bandwidth. The accuracy requirements on harmonics and requirements for the anti-aliasing filter are also given in BS EN 61869-6.
Note: BS EN 61869-6 does not cover the specification for the digital output format of instrument transformers.
BS EN 61869-6 on general requirements for low-power instrument transformers is relevant to:
Low-power instrument transformer is an arrangement, consisting of one or more current or voltage transformer(s) which may be connected to transmitting systems and secondary converters, all intended to transmit a low power analogue or digital output signal to measuring instruments, meters, and protective or control devices or similar apparatus.
Power system short-circuits currents contain alternating current (a.c.) and transient components. BS EN 61869-6 assists with low-power current transformer and low-power voltage transformer. Low-power current transformers have a wider range of applications than conventional CTs. Low-power current transformers, such as optical CTs and Rogowski coils, have linear characteristics and do not saturate. They can be applied for faults involving high currents and high d.c. components. BS EN 61869-6 also assists with low-voltage components which are all-electric or electrical components of an LPIT separated from the primary circuit at the full rated withstand voltage level. BS EN 61869-6 provides guidance on harmonic and inter harmonic disturbance. The purpose is to verify the immunity of the LPIT against harmonic and inter harmonic components of the low-voltage power supply of the LPIT. This test is only applicable for LPIT using a.c. power supply. BS EN 61869-6 also describes various other types of low-power current transformers.
Overall, BS EN 61869-6 is useful as it gives a list of type tests for electronic LPIT with the associated test levels and assessment criteria.
EN 61869-6:2016
IEC 61869-6:2016