Power instrument transformers (including current transformers and voltage transformers) are essential, critical equipment in power systems. Their core function is to safely convert high voltages and high currents to the low voltages and low currents required by measurement and protection equipment. They offer several significant advantages:
1. Ensuring the safety of personnel and equipment
Electrical isolation:
When high voltages (such as 10kV and 110kV) and high currents (such as hundreds to thousands of amperes) in power systems are directly connected to measurement or protection equipment, there is a significant risk of electric shock and equipment damage.
Instrument transformers electrically isolate the primary side (high voltage/high current) from the secondary side (low voltage/low current) through electromagnetic induction or photoelectric conversion. Secondary equipment (such as instruments and relays) is only exposed to low voltages (typically ≤100V) and low currents (5A or 1A), fundamentally preventing the safety hazard of high voltage directly affecting operators and secondary equipment.
Limiting the impact of faults:
If a fault such as a short circuit occurs on the primary side, the instrument transformer's inherent insulation design and protection features can reduce the impact of the fault current on secondary equipment, minimizing the likelihood of cascading damage.