Protection relays, CTs, VTs, LVCs, secondary circuits, trip systems, automation and communication engineering for medium-voltage switchgear.
Generator protection at medium-voltage switchgear must protect more than the stator. The scheme has to distinguish internal electrical faults from abnormal operating conditions, prime-mover problems, excitation failures and power-system disturbances—then trip the correct combination of generator breaker, field breaker, turbine…
A voltage transformer circuit can fail without any primary-system fault. A blown fuse, tripped miniature circuit-breaker, open test switch, loose terminal or broken wire can reduce one or more relay voltage inputs while the power system remains healthy. Unless the…
A neutral grounding resistor (NGR) deliberately limits single-line-to-ground fault current. If the resistor or its connection fails open, the system can become effectively ungrounded and its earth-fault protection may become blind. If it is shorted or bypassed, fault current can…
Cable differential protection is one of the most selective ways to protect a medium-voltage cable. It compares the current entering the cable with the current leaving it and trips when the difference indicates a fault inside the CT-defined zone. The…
A practical engineering guide to medium-voltage capacitor-bank protection, covering bank-specific unbalance methods, CT/VT selection, illustrative settings, trip logic and commissioning tests.
A structured engineering comparison of 59N and 64 protection, calculated 3V0, broken-delta voltage, VT requirements, settings, grounding methods, and commissioning tests.
A practical engineering guide to wire numbering in switchgear low-voltage compartments, covering IEC requirements, numbering philosophies, EPLAN implementation, marker selection, quality control and a worked 110 VDC trip-circuit example.
A practical engineering guide to G98, G99 and G100 for solar PV, battery storage, generators and V2G in Great Britain—including DNO applications, protection, export limitation, commissioning and a worked PV+BESS example.
A practical engineering guide to protecting MV incomers, outgoing feeders, transformers, motors and capacitor banks—with function matrices, trip logic, setting principles and official relay application diagrams.
Polarized DC miniature circuit breakers must be wired in the direction tested by the manufacturer. This guide explains arc physics, terminal markings, ABB SB200 DC diagrams, voltage-to-earth limits, and commissioning checks.
