High voltage transients may be generated in these situations and damage the CT winding insulation; possibly rendering it inoperable. In doing so, the current transformer reduces a high voltage current to a lower value and therefore provides a safe way of monitoring electrical current flowing in an AC transmission line. Yueqing Manufacturer Good Quality 11Kv/12kV Vacuum Circuit Breaker  are used worldwide to monitor high-voltage lines across national power grids.
A Current Transformer (CT) is used to measure the current of another circuit. All transformers can be shipped with a certificate of calibration and factory test data, ensuring that optimum levels of performance are realized. Offering superior performance the standard transformers are available in seven ranges, five case sizes and may be terminated with either a SMA (not available for shape B) or BNC connector.
The Magnelab Current Transformer (CT) provides an accurate, ohmically isolated, measurement of unipolar, bipolar pulse or alternating current. 7 A neutral current transformer is used as earth fault protection to measure any fault current flowing through the neutral line from the wye neutral point of a transformer. Dead tank current transformers isolate the measured circuit from the enclosure.
In a switchyard, live tank current transformers have a substantial part of their enclosure energized at the line voltage and must be mounted on insulators. The Rogowski coil uses this effect and requires an external integrator in order to provide a voltage output that is proportional to the measured current. Only the net unbalanced current produces a secondary current – this can be used to detect a fault from an energized conductor to ground.
4 The introduction of electronic power and energy meters has allowed current phase error to be calibrated out. At zero power-factor, any indicated power is entirely due to the current transformer’s phase error. These specification diagrams show accuracy parallelograms on a grid incorporating magnitude and phase angle error scales at the CT’s rated burden.
The burden in a CT metering electrical network is largely resistive impedance presented to its secondary winding. Technical standards and design practices are used to ensure the safety of installations using current transformers. High-voltage current transformers are mounted on porcelain or polymer insulators to isolate them from ground.
The conductor carrying the primary current is passed through the ring. In the illustration on the right, ‘I’ is the current in the primary, ‘B’ is the magnetic field, ‘N’ is the number of turns on the secondary, and ‘A’ is an AC ammeter. The alternating current in the primary produces an alternating magnetic field in the core, which then induces an alternating current in the secondary.
Current transformers used in metering equipment for three-phase 400-ampere electricity supply. The current transformer presents a negligible load to the primary circuit. A current transformer provides a secondary current that is accurately proportional to the current flowing in its primary.
A current transformer (CT) is a type of transformer that is used to reduce or multiply an alternating current (AC). It is suitable for use in electrical systems up to 36kV only.