The technological development of current transformers is undergoing a transformation from traditional equipment to intelligent, digital sensing elements. Its technological path has leaped from traditional electromagnetic to electronic, optical, and even quantum sensing technologies.
Traditional electromagnetic current transformers, with their advantages of simple structure and low cost, have long dominated the medium and low voltage market. Electronic current transformers achieve current measurement through techniques such as resistive voltage division or Rogowski coils. Combined with low-power coils and analog-to-digital converter chips, they directly output digital signals, solving the saturation and dynamic range problems of traditional equipment. Their size is only 1/3 to 1/5 that of electromagnetic transformers, and their resistance to electromagnetic interference is significantly improved. They are widely used in smart substations, new energy power generation plants, and other fields.
Optical current transformers, based on the Faraday magneto-optical effect, transmit signals through optical fibers, completely eliminating electromagnetic interference. They also possess advantages such as simple insulation, extremely wide dynamic range, and no magnetic saturation. However, they still face challenges in long-term operational stability, such as susceptibility to factors like temperature, vibration, and optical path loss. Quantum current transformers utilize quantum sensors, such as NV color centers, to sense magnetic fields, achieving high-precision, high-stability, and wide dynamic range AC/DC current measurement. This technology has already been commercially applied in the power industry, for example, in substation grid-connected operation.
The future development of current transformers will show a trend towards intelligence and digitalization, deeply integrating technologies such as the Internet of Things and big data, evolving into integrated "measurement-diagnosis-early warning" devices. By integrating sensors, communication modules, and edge computing chips, real-time data acquisition, local processing, and remote transmission can be achieved. In terms of digitalization, industry standards are gradually being improved, promoting enhanced product interchangeability. Current transformers will be deeply integrated with circuit breakers, disconnectors, and other equipment to form intelligent combined electrical appliances, reducing equipment footprint and installation costs. Simultaneously, products are developing towards miniaturization and modularization to adapt to the needs of smart grid transformation and distributed energy access.
With the advancement of "dual-carbon" goals and the construction of new power systems, higher requirements are being placed on the accuracy, reliability, and environmental adaptability of current transformers. For example, offshore wind farms require instrument transformers to be resistant to salt spray and corrosion; flexible DC transmission requires instrument transformers to support wideband measurement and fast response. To meet the requirements of green grids, oil-free and solid-state insulation are becoming trends, while simultaneously reducing operating energy consumption. Low-power wireless current transformers (CTs) employ energy harvesting technology, support wireless transmission, and are suitable for remote monitoring nodes. In addition to power systems, demand is also rapidly growing in emerging fields such as rail transit, industrial automation, data centers, electric vehicle charging stations, and industrial frequency converters.