ZLV – Distance Protection (“V” Platform)

Selective, Fast and Reliable Protection in Overhead Lines and Cables

ZLV relays provide distance protection for power transmission and subtransmission lines. They feature a complete package of functions and protection schemes offering selective, quick and reliable protection both for underground and overhead lines, with or without series compensation.

Key features

• Single or Double-breaker bay protection.
• 21/21N Distance protection for ground and phase faults.
• Up to 6 reversible protection zones with mono or three phase tripping systems.
• Sub-cycle operating time.
• 50SUP Overcurrent supervision for distance protection.
• 68/78 Lockout and/or trip due to power oscillation.
• 85 Teleprotection schemes for distance and overcurrent  elements.
• 50-51 / 50Q-51Q / 50N-51N Ovecurrent prot (ph+ground).
• 67 / 67Q / 67N Directional overcurrent prot (ph+ground).
• 27/59 Under/over voltage (phases).
• 59N Ground overvoltage.
• 81M/m Over/under frequency and rate-of-change protection.
• 49 Thermal image.
• 46 Open phase: I2/I1 (current unbalance).
• 50BF Breaker failure.
• 27WI Weak infeed logic.
• 50SOF Switch-on-to-fault detector.
• 50STUB Stub bus protection.
• 79 Recloser.
• FL Fault locator.
• 25 Synchrocheck.
• Mutual Coupling Compensation in Double Circuits.
• Saturation Detector.
• Load Encroachment logic.
• Phase Selector.
• Virtual I/Os for Teleprotection schemes.