Bus Differential and Breaker Failure Relay A Powerful Solution for Busbar Differential Protection Features and Benefits Select the for the differential protection of busbar systems with up to 18 terminals. Protection Protect bus systems with up to 18 terminals (54 CTs), 6 protection zones, and 1 additional independent check zone. To optimize protection security, the check zone supervises up to 6 zones, and a patented open CT detection algorithm blocks potential misoperations during open or shorted CT conditions. Differential and directional current elements provide increased security and fast fault detection. Reduce protection costs with built-in breaker failure protection. Flexibility Implement different ratio CTs and nondedicated CTs with the. Eliminate complex wiring by using CT ratios that differ by up to a factor of 1:1. Take advantage of the same CTs for differential protection, metering, backup relaying, and other functions. Automation and Control Reduce project costs and simplify interconnect wiring using multiple communications protocols and ports. Configurable operator controls and simplified variable naming provide added power to SELogic control equations. Monitoring and Metering Provide accurate, timely monitoring and metering of busbar, feeder, and substation signals. Terminal currents, breaker and disconnect positions, station dc voltage levels, and three-phase voltage are continuously monitored and updated. Making Electric Power Safer, More Reliable, and More Economical
Functional Overview HMI RTU DFR SBM SER LGC MET 85 RIO Operator Interface Remote Terminal Unit Event Reports Station Battery Monitor Sequential Events Recorder Expanded SELOGIC High-Accuracy Metering SEL MIRRORED BITS 16 S EC Access Security 4 2 1 * Optional Functions EIA-232 Ethernet* (Copper or Fiber-Optic) IRIG-B Integrate With Ethernet Networks Apply Relays with Ethernet directly to a local network or through an SEL communications processor. Use DNP3 LAN/WAN or Modbus TCP to quickly send information through your networks. Provide information to the right people for improved system performance. Transfer data with high-speed Ethernet for fast HMI updates and file uploads. Use popular Telnet applications for easy terminal communication with SEL relays and other devices. Combine IEC 6185 technology, Ethernet network, and the for the fastest overall performance of IEC 6185 relays for substation automation and control. Access basic relay information on a standard Ethernet network with the built-in web server. View relay status, Sequential Events Recorder (SER) reports, metering information, and settings. Web server access requires relay password and is limited to read-only viewing of information. Simplify wiring and installation by receiving a time signal over existing Ethernet networks. SNTP makes a good backup to more accurate IRIG-B time synchronization. SEL-351 SEL-2725 SEL-3351 Network SEL-351 SEL-232 SEL-351 Typical Ethernet network configuration. 2
Differential Protection The includes six independent current differential elements. Each differential element provides: Fast operate times for all busbar faults High-Security Operate Slope Standard Operate Slope Security for external faults with heavy CT saturation Security with subsidence current present Restraint Zone High sensitivity to busbar faults Minimum delay for faults evolving from external to internal CT Supervision Current Input I 1 I OP Differential Element 2 15 Slope 2 Slope 1 Trip Output Current (amperes) 1 5 5 5 Fault Inception IO1 IO2 Internal Fault Detection (<1 cycle) Time Differential element operation in less than one cycle for internal faults, including high-speed contact closure. Current Input I 18 Fault Detection Logic External faults are detected by directional elements within the relay. When an external fault is detected, the relay enters a high-security mode and dynamically selects a higher slope for the differential elements, making them more secure during the fault. I RT External Fault Internal Fault 1 5 Current (amperes) 5 5 5 1 15 IO1 IO2 Internal Fault Detection (No Differential Element Operation) CT Supervision For each zone, sensitive current differential elements detect differential current resulting from a differential element that is not well balanced (i.e., wrong CT ratios). If the conditions persist for longer than a user-specified delay, the element alarms and can be used to generate an external alarm and/or block the zone. Voltage Element Supervise current differential tripping within the relay using voltage elements. Three separate voltage elements consist of two levels of phase under- and overvoltage elements and two levels of negative- and zero-sequence overvoltage elements for each of the three analog voltage quantities measured. Time Differential element remains secure for external faults with CT saturation. Overcurrent Elements Choose from ten overcurrent curves for each current input. Each torque-controlled, time-overcurrent element has two reset characteristics. There is also one level of instantaneous and definite-time elements available for each current input. 3
Breaker Failure Detection Open-Phase Detection The includes complete breaker failure protection, including retrip, for each terminal. Internal breaker failure is determined by predefined protection schemes that allow different types of trip signals and current flow conditions. External breaker failure device inputs can be substituted for the internal breaker failure schemes, while providing individual or identical responses to each breaker failure condition. Open-Phase Detection High-speed, open-pole detection logic detects open-pole conditions in less than.75 cycles to reduce breaker failure coordination times. Dynamic Zone Configuration The dynamically assigns the input currents to the correct differential elements without the need for additional auxiliary relays. Connect the digital inputs from the busbar disconnect and breaker auxiliary contacts directly to the relay. SELogic control equations and zone selection logic will correctly assign the currents to the differential elements, even for complex bus arrangements as shown (Figure A). Note that the automatically includes the Zone 4 currents in Zone 3 when Disconnect Switch DS3 is closed (Figure B). Figure A. Figure B. 4
Advanced Open CT Detection Logic The patented open CT detection logic improves the security of the current differential element. It assures current differential bus zones will not misoperate due to terminals that cannot be properly measured. This advanced logic, when implemented, will block differential element misoperations that occur under open or shorted CT conditions. The CT detection logic monitors the CT terminals in every bus zone to detect when a contributing CT has failed. Independent Check Zone Supervises Up to Six Differential Bus Zones In complex busbar layouts, the uses disconnect auxiliary contact status to define current differential bus zones and supervises these zones with the independent check zone feature to prevent misoperation due to discrepancy. Check Zone Key Features Provides secure supervision for bus zones Supervises bus zones independently of terminal auxiliary disconnect status Processes its logic independently of all bus zones Fits a wide variety of applications and protection philosophies with independent pickup and slope settings Three-Relay Bus Protection Application For Up to 18 Terminals A single-phase check zone is provided per relay. A three-phase (A,B,C) check zone will require three relays. Configure a check zone for every phase, encompassing all terminals at the station (except bus coupler and sectionalizing breakers), independent of disconnect auxiliary contact status. LONDON Zone 1 BERLIN NEW YORK Zone 1 Zone 2 Check Zone Check Zone Zone 2 This is a basic example of a check zone supervising only two three-phase zones, with one per phase. These three Relays can supervise up to six three-phase zones. CANBERRA acselerator Software acselerator QuickSet SEL-53 Develop settings and busbar configurations offline with acselerator QuickSet. The system automatically checks interrelated settings and highlights out-of-range settings. Settings created offline can be transferred to the by using a PC communications link. Graphical Logic Editor (GLE) Simplify the process of configuring your using the GLE in acselerator QuickSet SEL-53 Software. The GLE allows you to view your SELogic equations graphically, so your settings files can be documented for easier validation and commissioning. Convert existing SELogic control equations to easy-to-read diagrams, and save diagrams with your QuickSet settings. acselerator graphical logic editor (GLE). 5
Automation and Control The control logic can replace the following: Traditional panel control switches RTU-to-relay wiring Traditional latching relays Traditional indicating panel lights Panel meters Eliminate traditional panel control switches with 32 local control points. Set, clear, or pulse local control points with the programmable front-panel pushbuttons and display. Program the local control points to implement your control scheme via SELogic control equations. Eliminate RTU-to-relay wiring with 32 remote control points. Set, clear, or pulse remote control points via serial port commands. Incorporate the remote control points into your control scheme via SELogic control equations. Apply remote control points for SCADA-type control operations, such as trip and group selection. Advanced Display and Controls for Next-Generation Substation Automation and Integration Rotating display automatically scrolls between custom metering displays, alarms, event summaries, and preconfigured fundamental line quantity displays. SEL provides a worldwide, ten-year product warranty and 4 to +85 C operating temperature range the best in the industry. Easy-to-use keypad aids simple navigation and set-point adjustment. Detailed, programmable target LEDs with user-configurable labels give fast and simple information to assist dispatchers and line crews in rapidly restoring power. Optionally, add eight tricolored target LEDs. Breaker status indication. Enhanced Front-Panel HMI Improve efficiency and simplify installation with more target LEDs and operator buttons. The 7U and 9U chassis have options for an additional eight target LEDs and four operator control buttons. Indicate relay state and various trip conditions with 24 target LEDs, or configure the LEDs for specific applications. Meet operator control needs by modifying the 12 operator buttons to replace traditional panel switches, and control more circuit breakers. Service control switch. The front-panel LCD shows the latest 2 of the 1, events time-stamped in the Sequential Events Recorder (SER). Programmable operator pushbuttons and configurable labels provide local switches to replace traditional panel switches. Optionally, add four tricolored operator pushbuttons to control even more circuit breakers. 6
Monitoring and Metering Access Useful Information Metering quantities include primary and secondary voltage and current magnitudes, and angles for each terminal. Zone information displays primary or secondary current and voltage for each terminal. The polarity of each CT and the bus zones in each of the protective zones at the station are also included. Differential metering shows the operating and restraint currents for each zone as well as the reference current. Battery monitoring provides warning and alarm thresholds that can be monitored with the SEL-232/23/22 Communications Processor. Trigger messages via local display, telephone, pager, or other devices. Simplify System Testing and Post-Fault Analysis The event reporting capabilities help improve understanding of even the most complex protective scheme operations. SER Gain a broad perspective of relay element operation with the SER in the. Items that trigger an SER entry are selectable and can include as many as 25 monitoring points, such as input/ output, change of state, element pickup/dropout, and more. The relay SER stores the latest 1, events, which are available through the SER command. The latest 2 events are also viewable via the front-panel LCD. Illustrated here is security during an external fault with CT saturation. The stores up to 48 cycles (8 seconds), in either 15-, 3-, 6-, or 12- cycle event reports, at 24 samples per cycle in nonvolatile memory. Relay settings are appended to the end of each report. Illustrated here is security during MOV arrester conduction. User-selected internal or external triggers can be used to generate oscillographic event reports that include voltage, current, and element status information. acselerator Analytic Assistant SEL-561 Software helps you compare event reports from multiple relays, enhancing this powerful tool s analytic capabilities. 7
Bus Differential and Breaker Failure Relay General Specifications AC Current Inputs (secondary circuits) 5 A nominal 15 A continuous, linear to 1 A symmetrical, 5 A for 1 second, 125 A for 1 cycle Burden.27 VA @ 5 A; 2.51 VA @ 15 A 1 A nominal 3 A continuous, linear to 2 A symmetrical, 1 A for 1 second, 25 A for 1 cycle Burden.13 VA @ 1 A; 1.31 VA @ 3 A AC Voltage Inputs 3 V L-N continuous (connect any voltage up to 3 Vac) 6 Vac for 1 seconds Burden.3 VA @ 67 V;.6 VA @ 12 V;.8 VA @ 3 V Power Supply 125/25 Vdc or 12/24 Vac Range 85 3 Vdc <35 W or 85 264 Vac (3 12 Hz) Burden <12 VA 48/125 Vdc or 12 Vac Range 38 14 Vdc <35 W or 85 14 Vac (3 12 Hz) Burden <12 VA 24/48 Vdc Range 18 6 Vdc Burden <35 W Station DC Battery System Monitor Specifications Operating Range 35 Vdc Input Sampling Rate 24 samples per cycle Processing Rate 1/6 cycle Maximum Operating Time ±1.5 cycles (all elements but DC1R) ±1.5 seconds (element DC1R) Setting Range DC Settings OFF, 15 3 Vdc, 1 Vdc steps AC Ripple Setting 1 3 Vac, 1 Vac steps Accuracy Pickup Accuracy ±3%, plus ±2 Vdc (all elements but DC1RP) ±1%, plus ±2 Vdc (DC1RP) Serial Communications Ports Three rear-panel and one front-panel EIA-232 ports. SEL ASCII Commands, SEL Fast Messages, DNP3 Serial Data Speed 3 576 bps Ethernet Communications Options Provides IEC 6185, DNP3 LAN/WAN, FTP, Telnet protocols, and web server capabilities. Ethernet connection media options: 1/1BASE-T Twisted-Pair Network 1/1BASE-FX Fiber-Optic Network 1 Metering Accuracy All metering accuracies are based on an ambient temperature of 2 C and nominal frequency. Instantaneous Differential Metering Per Zone I OP, I RT ±5.%, ±.2 I NOM Per-Phase Instantaneous Metering and V 1, V 2, and V 3 I 1, I 2,..., I 18 ±3% ±.4 I NOM, ±2. Conformal Coating Option Protect equipment from harsh environments and airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture. Chassis Options 9U chassis supports up to 4 optional I/O boards 7U chassis supports up to 2 optional I/O boards Relay provides many I/O port options (9U version shown). 1 Eye-safe, Class 1 LED device per EN 6825-1 Pullman, Washington USA Tel: +1.59.332.189 Fax: +1.59.332.799 www.selinc.com info@selinc.com 25 21 by Schweitzer Engineering Laboratories, Inc. PF63 211111