Siemens Siprotec 4 SIPROTEC 7SJ61 Overcurrent Protection Relay

The SIPROTEC 4 7SJ61 Overcurrent Protection Relay can be used for line protection of high and medium voltage networks with earthed (grounded), low-resistance earthed, isolated or compensated neutral point. When protecting motors, the SIPROTEC 4 7SJ61 is suitable for asynchronous machines of all sizes. The relay performs all functions of backup protection supplementary to transformer differential protection.The relay provides control of the circuit breaker, further switching devices and automation functions. The integrated programmable logic (CFC) allows the user to implement their own functions, e. g. for the automation of switchgear (interlocking). The user is also allowed to generate user-defined messages. The flexible communication interfaces are open for modern communication architectures with control systems.

PROTECTION FUNCTIONS

• Overcurrent protection (definite-time/inverse-time/user-def.)
• Sensitive earth-fault detection
• Intermittent earth-fault protection
• High-impedance restricted earth fault
• Inrush – Current detection
• Motor protection
  – Undercurrent monitoring
  – Starting time supervision
  – Restart inhibit
  – Locked rotor
  – Load jam protection
• Overload protection
• Temperature monitoring
• Breaker failure protection
• Negative-sequence protection
• Auto-reclosure
• Lockout

CONTROL FUNCTIONS/PROGRAMMABLE LOGIC

• Commands for control of a circuit-breaker and of isolators
• Position of switching elements is shown on the graphic display
• Control via keyboard, binary inputs, DIGSI 4 or SCADA system
• User-defined logic with CFC (e.g. interlocking)

MONITORING FUNCTIONS

• Operational measured values
• Circuit-breaker wear monitoring
• Slave pointer
• Time metering of operating hours
• Trip circuit supervision
• 8 oscillographic fault records
• Motor statistics

COMMUNICATION INTERFACES

• System interface
  – IEC 60870-5-103, IEC 61850
  – PROFIBUS-FMS/-DP
  – DNP 3.0/MODBUS RTU
• Service interface for DIGSI 4 (modem)
• Front interface for DIGSI 4
• Time synchronization via IRIG B/DCF77

HARDWARE

• 4 current transformers
• 3/8/11 binary inputs
• 4/8/6 output relays

SIPROTEC 4 leads the way in integrating protection, control, measurement, and automation functions in one device. The homogenous system platform, the unique DIGSI 4 engineering program, and extensive experience of more than a million successfully operating devices in the field worldwide – thanks to these unique advantages, SIPROTEC 4 enjoys top recognition among users worldwide. SIPROTEC 4 is the industry standard for digital protection technology today in all fields of application.