Simplifying the configuration of multifunctional distribution protection and control IEDs

The last ten years have seen significant changes in the development of multifunctional Intelligent Electronic Devices (IEDs) with primarily protection functions. The number and complexity of the protection and non-protection elements, as well as the availability of multiple setting groups allows the implementation of advanced and adaptive distribution protection schemes. The main problem with the advancements in the functionality of modern protective relays is the increased complexity of the setting of the IEDs. The protection engineer has to configure hundreds of settings and the user programmable scheme logic in order to ensure the optimal performance of the relay under different system conditions. The paper analyses the different functions in state-of-the-art numerical relays, as well as their functional hierarchy from the point of view of the configuration requirements. Three main levels of this hierarchy are identified and described: Functions, Sub-functions and Functional elements Tools that significantly simplify the configuration of protection relays include visibility control and automatic setting calculation based on the protected equipment nameplate data. Examples of the configuration of complex transformer protection relays are presented. Programmable scheme logic in advanced distribution protection relays usually requires a multistep process with increased complexity and probabilities for errors at the different steps. Graphical tools that significantly simplify that development are described later in the paper. The status of development of a common IED configuration data file format by a working group in the IEEE Power Systems Relaying Committee based on XML and the object models defined in IEC 61850 is discussed also in the paper. This will allow the development of universal IED setting tools and will significantly simplify their configuration process.