Photoelectric transformer types and their advantages

Photoelectric transformers can be divided into two types. One is to use magneto-optical and electro-optic effects to directly convert current and voltage into optical signals, commonly referred to as passive, and the other is to convert current and voltage signals into small voltage signals using the principle of electromagnetic induction or partial voltage, and then to apply small voltages. Signals are converted to optical signals for transmission to secondary equipment, commonly referred to as active. Because of the problems of stability, poor producibility, and complex electronic circuits, passive systems are now mainly in the laboratory stage, and it will take time to promote them. The difficulty of the active type is to provide the working power needed at the high voltage end, but with the breakthrough of the laser power supply and high voltage power acquisition technology, it has been fundamentally solved. There are two ways in which the source of energy can be sensed in the photoelectric head of a photoelectric transformer. One is to take energy from one time. The energy is induced by the energy coil to provide energy. When the primary current is too small to provide energy, the energy optical cable is used. The indoor laser generator sends energy through the optical cable. The two modes are mutually standby and automatically switch.

Compared with traditional electromagnetic transformers, optoelectronic transformers have obvious advantages: (1) In high voltage, high current measurement environments, optical fiber or optical medium is a good insulator, it can meet the insulation requirements under high voltage working environment (2) There is no danger of the traditional open-circuit high voltage generated by the traditional current transformer, and the risk of oil leakage and explosion of traditional oil-filled voltage and current transformers. (3) It does not produce magnetic saturation and ferromagnetic resonance. It is especially suitable Fault diagnosis under high voltage and high current environment; (4) Frequency bandwidth, from DC to several hundred kilohertz, suitable for relay protection and harmonic detection; (5) Large dynamic range, large dynamic range Highly linear response within the system; (6) Adapting to the digital signal processing requirements of current power systems. It can also be used for high-speed remote sensing and telemetry systems for protection, monitoring, and measurement purposes; (7) Compact and weight measuring devices Light, small size; (8) Each function module is relatively independent, easy to install and maintain, suitable for networked measurement.

Due to the many advantages of photoelectric transformers, it will only be a matter of time before photoelectric transformers replace traditional transformers. Internationally, optoelectronic transformers have gradually matured and are being applied more and more quickly. Among them, photoelectric transformers produced by ABB, Siemens and other companies have been successfully operating for more than ten years. Digital substations using photoelectric transformers have also been put into operation in Europe. The development and application of optoelectronic transformers in our country are relatively backward, and only a few substations use some imported photoelectric transformers.