With the application of a lot of new materials, transformer, there have been many new types of electromagnetic transformers have been more fully developed, in which the core current transformer with dry, oil-immersed and gas-insulated type variety of structures adapted to the development needs of the electric power construction. However, with the increasing power transmission capacity of the grid voltage level continues to improve and continue to improve the protection requirements of Hangzhou high voltage transformer, current transformer core general structure has been gradually exposed the weakness of Wenzhou incompatible with high voltage transformer, its inherent bulky, magnetic saturation, ferromagnetic resonance, small dynamic range, use narrow band weaknesses, it is difficult to meet the new generation of full hard power system automation, power digital network development needs. Transformers including CT and PT, is a high current, high voltage into a low current, low voltage for each measurement to protect the coil high voltage power transformers, electrical equipment reflects the operating parameters and fault conditions of the electrical equipment. (1) CT is equivalent to a short circuit operation of the transformer secondary winding in series with the metering and protection, rated current of 5A or 1A, allowed to open. Principle one side N1 or less is usually a turn a few turns, N2 bigger. I1 depends entirely on the primary current (load current) nothing to do with I2 and load changes. This is different from the transformer. Under normal circumstances, the impedance of the second series of instruments and relays the current through the coil is very small, close to a short Jiaxing high voltage transformer, which is another different point from the power transformer. When the current transformer is working properly, the secondary current of the magnetomotive force generated by the secondary of a magnetomotive force I1N1 I2N2 from demagnetization effect. Therefore, the synthesis of magnetic potential I0N1 and synthetic flux value is not large, the secondary induced emf E2 value does not exceed several tens of volts. (2) PT is equivalent to an open transformer running, secondary and measurement, voltage coils in parallel to protect the instrument, rated voltage of 100V, not allowed to short circuit. Principle N1 "N2, secondary impedance is large, almost in no-load state, U2 does not affect U1, and with the changes reflect a voltage U1. Ningbo high voltage transformer | Huayi Electric Power (certified) | high voltage transformers supplied by Xian Huayi power plant. Xian Huayi power plant (www.xahy.com) is a leader in Xi'an, high voltage circuit breakers, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Huayi power in leadership with the staff warmly welcome all inquiries negotiations to create electricity Huayi a better future.