Innovation continues to drive our success. Solving challenging problems for our customers helps SEL develop new technologies that become available for everyone’s benefit. Synchrophasors for wide-area protection and control, arc-flash hazard detection for protection of people and equipment, cybersecurity to prevent unwanted access, and conformal-coated circuit boards for robust operation in contaminated environments are just a few of the technologies available.
Arc Sense technology (AST) from SEL is an innovative solution that detects high-impedance faults (HIF) on a distribution system. A high-impedance fault occurs when a conductor contacts a ground surface but does not produce a large fault current. SEL’s patented AST detects and clears faults that might not be detected by conventional overcurrent elements. AST algorithms provide improved fault detection over traditional methods as well as enhanced security when compared to existing technologies. Dedicated event reports provide information on high-impedance fault activity for event analysis.
These events commonly occur in a distribution system, emphasizing the need for the integration of the AST solution into SEL’s distribution relays and the SEL-651R Advanced Recloser Control.
An algorithm has been designed to improve the accuracy of the devices’ detection capabilities. To ensure the accuracy and reliability of the HIF detection, the algorithm gathers different data to make the best possible decision. Our patented Sum of Difference Current (SDI) method uses the current rate of change to detect arcing results from events such as downed conductors. The necessary elements used for the algorithm are implemented in the block diagram below, with five easy steps.
Conformal coating is specially formulated to protect PCBs and related equipment from the environment. This improves and extends the working life of the PCB and ensures security and reliability. The coating conforms to the shape of the board and its components, creating a protective layer that is both lightweight and flexible.
This durable protective coating protects circuitry from hazards such as chemicals (e.g., fuels, coolants, etc.), vibration, moisture, salt spray, humidity and high temperature, fungus, corrosion, and thermal shock.
SEL products with conformal coating have been tested and approved by independent testing laboratories to the following specifications for mixed flowing gas, hygroscopic dust, and damp heat:
Mixed flowing gas includes contaminants Cl2, H2S, NO2, and SO2.
Hygroscopic dust includes water-soluble salts, sulfate, nitrites, volatile organic compounds, SO2, H2S, ammonia, NO, NO2, HNO2, ozone, and gaseous chlorine.
SEL meets Mil-1-46058C Type UR conformal coating requirements. Material used for conformal coating is approved to the following specifications:
Connectorized products offer the advantage of robust connections while minimizing installation and replacement time. Now, installing or removing an SEL device with Connectorized terminals only takes a few minutes. All wiring remains connected to the terminal blocks. Each terminal block mates with a connector in the SEL device. Each connector features positive-retention screws to prevent accidental disconnection due to the weight of wire bundles, vibration, or physical shock.
We provide the following styles of proven, high-reliability terminal blocks.
Each of these connectors has been thoroughly tested by its manufacturer and proven over time in many industry applications. In addition, SEL tested these connectors to verify conformance to our standards for protective relay applications.
IEC 61850 was created to be an internationally standardized method of communication and integration and to support systems built from multivendor intelligent electronic devices (IEDs) that are networked to perform protection, monitoring, automation, metering, and control. Combine IEC 61850 technology, Ethernet networking, and SEL high reliability to perform station computing and protection, automation, and control for distance, current differential, distribution, transformer, bus, motor, and bay control applications.
La Venta II Substation in Mexico
Wind Park La Venta II is the world's first substation to show IEC 61850 in action within protective relays for a wide variety of vendors and to prove interoperability among these devices.
Thirty-Substation Modernization Project in Brazil
This project includes the complete modernization of 30 distribution substations belonging to Elektro Eletricidade e Serviços S.A., a large electric distribution utility in Brazil.
PPL Next-Generation Substations
Replacing hard-wired connections with digital communications over Ethernet networks requires new engineering and testing practices. PPL Electric Utilities Corporation designed, installed, and tested a new high-voltage substation using next-generation relay and control equipment. This next-generation substation is based on networked Ethernet IEDs communicating via IEC 61850.
RTU Replacement in the United States
An electric utility distribution group replaced pad-mounted switch remote terminal units with SEL-2411 Programmable Automation Controllers communicating via IEC 61850 links. They needed various I/O types and an easily scalable solution to support the different I/O requirements for each of three types of switches.
IEEE C37.94 is the only standard that provides plug-and-play transparent communications between different manufacturers’ teleprotection and multiplexer devices using multimode optical fiber. The standard defines clock recovery, jitter tolerances, physical connection method, and the equipment-failure actions for all communications link failures.
Historically, interface standards between teleprotection equipment and multiplexers were electrical only. Those high-speed (56–64 kbps), low-energy signal interfaces are vulnerable to intrasubstation electromagnetic and radio frequency interference (EMI/RFI), signal ground loops, and ground potential rise, which considerably reduce the reliability of communications during electrical faults.
Today, the safest and most reliable protection communications schemes in the industry dedicate optical fibers to intrasubstation communications links between protection (digital relays) and telecommunications (multiplexers) devices. Optical fibers do not have ground paths and are immune to noise interference, which eliminates data errors common to electrical connections. The IEEE C37.94 standard allows implementation of any protocol because there are no restrictions to the content of the data stream. Indeed, any data streams can be sent as long as the physical and signal-timing requirements are met.
SEL developed Mirrored Bits communications to provide high-speed, secure, point-to-point communication of real or virtual contact-status bits. Protection applications include directional element-based bus protection and replacement of tone-channel equipment for communications-assisted blocking, unblocking, permissive, and transfer trip schemes. Automation applications include high-speed sectionalizing, restoration and interlock schemes, and replacement of large bundles of field wiring with several small optical fibers, lowering costs and improving reliability.
Mirrored Bits communications is an innovative, low-cost, relay-to-relay communications technology that exchanges the status of eight internal logic points called Mirrored Bits, encoded in a digital message, from one device to another. This patented technology opens the door to numerous protection, control, and monitoring applications that would otherwise require more expensive external communications equipment wired through contacts and control inputs. Applications for Mirrored Bits communications include line protection pilot schemes, remote device control and monitoring, relay cross-tripping, and more.
The received Mirrored Bits (RMBs) of one relay follow the status, or "mirror" the status, of the respective transmit Mirrored Bits (TMBs) sent from the other relay. Each of the relays in the scheme repeatedly sends and receives the digital message while continually monitoring and checking the received message integrity. An internal monitoring point asserts when a good signal is received and deasserts immediately upon detection of a bad message. Other elements are also available for channel alarming and availability.