Description The combined SIPROTEC 7SL87 differential and distance protection has specifically been designed for the protection of lines. With its modular structure, flexibility and the powerful DIGSI 5 engineering tool, the SIPROTEC 7SL87 device offers futureoriented solutions for protection, control, automation, monitoring, and Power Quality - Basic. Main function Differential and distance protection Interoperability of SIPROTEC 4 and SIPROTEC 5 line protection devices Tripping 1-pole and 3-pole, minimum tripping time: 9 ms Inputs and 12 predefined standard variants with 4/4 or outputs 8/8 current/voltage transformers, 5 to 31 binary inputs, 8 to 46 binary outputs Hardware fle- Flexibly adjustable I/O quantity structure xibility within the scope of the SIPROTEC 5 modular system Housing 1/3 x 19 inch to 2/1 x 19 inch width Applications • Line protection for all voltage levels with 1 -pole and 3-pole tripping • Phase-selective protection of overhead lines and cables with single-ended and multi-ended infeed of all lengths with up to 6 line ends • Also used in switchgear with breaker-and-a-half layout • Transformers and compensating coils in the protection zone • Detection of ground faults in isolated or arc-suppres-sion-coilground power systems in star, ring, or meshed arrangement • Serial protection communication with SIPROTEC 5 and SIPROTEC 4 devices over different distances and physical media, such as optical fiber, two-wire connections, and communication networks • Phasor Measurement Unit (PMU) SIPROTEC 5 Device with Expansion Module • Detection and recording of power-quality data in the medium-voltage and subordinate low-voltage power system Functions DIGSI 5 permits all functions to be configured and combined as required. • Minimum tripping time: 9 ms • Main protection function is differential protection with adaptive algorithm for maximum sensitivity and stability even with the most different transformer errors, current-transformer saturation and capacitive charging currents • Several distance-protection functions selectable as backup protection or secondary main protection: Classic, reactance method (RMD), impedance protection for transformers • Directional backup protection and various additional functions • Adaptive power-swing blocking, out-of-step protection • Detection of ground faults of any type in compensated or isolated electrical power systems using the following functions: 3I0>, V0>, transient ground fault, cos 0, sin 0, harmonic, dir. detection of intermittent ground faults, harmonic detection, and admittance measuremen

Ground-fault detection using the pulse detection method Detection of current-transformer saturation for fast tripping with high accuracy Fault locator plus for accurate fault location with in-homogenous line sections and targeted automatic overhead-line section reclosing (AREC) Arc protection Automatic frequency relief for underfrequency load shedding, taking changed infeed conditions due to decentralized power generation into consideration Directional reactive power undervoltage protection (QU protection) Detection of current and voltage signals up to the 50th harmonic with high accuracy for...