Overview

The S24 Variant 3 is used mostly as the main or backup protection of overhead lines or cable feeders in distribution networks. The main protection function of this configuration is the distance protection function.

It is a member of the S24 series, which is part of the EuroProt+ Smart Line. Members of the Smart Line also offer a wide range of functions but they do so in a small, compact enclosure so that they can be installed in locations with limited space available for the protection equipment.

The S24 series contain special selections of the EuroProt+ modules and functions, composed with cost effectiveness in mind. Depending on the standard configuration chosen (Variant 1, Variant 2,…), the IED is adapted to the protection of medium-voltage feeders in isolated neutral, resistance earthed, compensated and solidly earthed networks. Once the application-specific settings have been defined for the standard configuration IED, it can be put into service directly. Areas of application include protection functions for a large variety of applications, e.g. transformer differential and restricted earth fault protection, frequency and voltage based protection, motor protection, thermal overload protection.

The EuroCAP configuration tool, which is available free of charge, offers a user-friendly and flexible application for protection, control and measurement functions to ensure that the IED-EP+ S24 devices are fully customisable.

General features

• Native IEC 61850 IED with Edition 2 compatibility
• Standard module layouts with options
• 24 HP wide rack size (height: 3U)
• The pre-defined factory configuration can be customized to the user’s specification with the powerful EuroCAP tool
• Different HMI types: advanced HMI with color touchscreen and black-and-white display with 4 tactile push buttons. An embedded web server and extended measuring, control and monitoring functions are also available for both types
• User configurable LCD user screens for the HMI-type color touchscreen, which can display SLDs (Single Line Diagrams) with switchgear position indication and control as well as measuring values and several types of controllable objects
• Various protection setting groups
• Enhanced breaker monitoring and control
• High capacity disturbance recorder (DRE) and event logging:
• DRE for up to 32 analogue and 64 digital signal channels
• Event recorder can store more than 10,000 events
• Mounting methods: Flush mounting; Semi-flush mounting; Din rail mounting
• Wide range of communication protocols:
• Ethernet-based communication: IEC61850; IEC60870-5-104; DNP3.0 TCP; Modbus TCP
• Serial communication: DNP3.0; IEC60870-5-101/103; MODBUS, SPA
• Legacy network based protocols via 100Base-FX and 10/100Base-TX (RJ45)
• Optional communication ports: Fiber optical Ethernet (MM/ST, SM/FC), RJ45, Serial POF, Serial glass fiber, RS-485/422
• Handling of several communication protocols simultaneously
• Built-in self-monitoring to detect internal hardware or software errors
• Different time sources available: NTP server; Minute pulse; Legacy protocol master

Application

Variant 3 is used mostly as the main or backup protection of overhead lines or cable feeders in distribution networks and motors. It is a member of the S24 series, which is part of the EuroProt+ Smart Line.

The main protection function of the Variant 3 relay is the 5-zone distance protection function. The configuration includes the simplified version of this function: it generates three-phase trip commands, but in the event of cross-country faults it also makes use of the phase preference logic. Additionally, Variant 3 includes a variety of versatile feeder protection functions such as three-phase, residual and negative sequence overcurrent protection, thermal overload protection, etc. The voltage measurement adds directionality extension to the configured phase and residual overcurrent function, under- and overpower functions in addition to the three-phase under- and overvoltage and residual overvoltage functions. Frequency-based functions are also available. It can be used as a back-up protection relay for downstream equipment (e.g. feeders, cables). The synchrocheck and automatic reclosing functions are also part of the standard configuration.

The IED includes a wide range of control and supervisory functions, which provide full control and user-defined interlocking schemes for the primary switchgear at the substation.

SCOPE OF APPLICATION

•      Distance protection function, overcurrent, directional overcurrent and thermal overload protection functions for overhead lines and cable feeders
•      Over- and undervoltage, residual and negative sequence overvoltage protection functions
•      Frequency-based functions
•      Over- and underpower function
•      The implemented protection functions provide back-up protection for downstream equipment (e.g. feeders, cables etc.)
•      Synchrocheck and automatic reclosing function
•      Breaker failure protection function
•      Current unbalance detection of CT’s
•      VT supervision function
•      Programmable interlocking schemes

Protection & control functions

The Variant 3 configuration measures the three phase currents, the residual current component as well as three phase voltages and the zero sequence voltage component. These measurements allow, in addition to the current- and voltage-based functions, directionality extension of the configured phase and residual overcurrent functions.

The main protection function in this application is the distance protection function. The configuration includes the simplified version of this function: it generates three-phase trip commands, but in the event of cross-country faults it also makes use of the phase preference logic. The scope of functions is supplemented with the automatic reclosing function.

Based on the voltage measurement, the frequency is also evaluated to realize frequency-based protection functions. The configuration is designed to meet the protection requirements of a medium-voltage field unit.

Documentation

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