Siemens Siprotec 5 7SD87 Line Differential Protection Relay

The line differential protection SIPROTEC 7SD87 Line Differential Protection Relay is part of the advanced SIPROTEC 5 Protection Relay Series, which offers modular, flexible, and intelligent digital field devices. Moreover, this relay is designed to meet the protection needs of modern electrical networks. Additionally, its modular design provides high adaptability for various substation configurations.

Furthermore, when used with the high-performance DIGSI 5 Engineering Tool, the SIPROTEC 7SD87 fits perfectly for protection, control, monitoring, and measuring applications in electrical energy systems. As a result, utilities and industries can enhance grid reliability and operational efficiency.

Main Function

• Firstly, differential protection ensures accurate detection and isolation of faults on transmission lines.

Tripping

• Additionally, the relay supports both 1-pole and 3-pole tripping.

• Moreover, it offers a minimum tripping time of 9 ms. Therefore, faults can be cleared quickly to maintain system stability.

Inputs and Outputs

• The device provides 12 predefined standard variants with 4/4 or 8/8 current and voltage transformers.

• Additionally, it supports 5 to 31 binary inputs.

• It includes 8 to 46 binary outputs, enabling flexible system integration.

Hardware Flexibility

• The relay features a flexibly adjustable I/O quantity structure within the scope of the SIPROTEC 5 modular system.

• Consequently, engineers can configure the relay according to specific project requirements.

Housing

• Finally, the housing width ranges from 1/3 × 19” to 2/1 × 19”, therefore allowing convenient installation in different control panel configurations.

All functions can be configured freely with DIGSI 5. For the application of some of the functions, you require the appropriate number of free function points within the device. The function point calculator in the online configurator provides support in determining the required number of function points for your device.

Function

• Minimal tripping time: 9 ms for fast and reliable fault clearance.

• Differential protection with an adaptive algorithm ensures high sensitivity and stability during transformer faults.

• Maintains reliable operation even with transformer errors, CT saturation, and capacitive charging currents.

• Detects ground faults in isolated or arc-suppression-coil grounded systems using 3I0>, V0>, Cos/Sin Phi, harmonic, and admittance methods.

• Identifies intermittent ground faults through directional detection techniques.

• Supports ground fault detection using the pulse location method for improved fault identification.

• Provides current-transformer saturation detection for accurate protection performance.

• Includes arc protection to enhance equipment and system safety.

• Offers automatic frequency relief for load shedding during underfrequency conditions.

• Considers changing infeed conditions from decentralized power generation during frequency disturbances.

• Provides power protection configurable for active or reactive power monitoring.

• Includes reactive power undervoltage protection (QU protection).

• Measures current and voltage signals up to the 50th harmonic for precise protection and monitoring.

• Supports 1-pole or 3-pole automatic reclosing functions.

• Includes control, synchrocheck, and switchgear interlocking protection for safe switching operations.

• Features a graphical logic editor for creating advanced automation functions.

• Displays single-line diagrams on small or large integrated device displays.

• Provides integrated Ethernet RJ45 for DIGSI 5 engineering and IEC 61850 communication.

• Supports up to four pluggable communication modules for IEC 61850, IEC 60870-5-103/104, Modbus TCP, DNP3, and PROFINET IO.

• Enables secure serial protection communication via optical fiber, two-wire connections, and communication networks.

• Allows automatic switchover between ring and chain communication topologies.

• Supports PRP and HSR redundancy protocols for high network reliability.

• Includes cybersecurity features aligned with NERC CIP and BDWE requirements.

• Functions as a Phasor Measurement Unit (PMU) with IEEE C37.118 protocol support.

• Supports precise time synchronization using IEEE 1588.

• Provides powerful fault recording up to 80 s at 8 kHz or 320 s at 2 kHz.

SIPROTEC 7SD87

SIPROTEC 5 is part of the new generation of incomparable modular, flexible, and intelligent digital field devices. With modularly designed hardware and software and its high-performance DIGSI 5 engineering tool, the SIPROTEC 5 product family of field devices is perfect for protection, control, monitoring, and measuring applications in electrical energy systems. SIPROTEC 5 offers a wide product range with modular elements for every application and requirement.