Photoelectric sensorIt is a device that converts optical signals into electrical signals. Its working principle is based on the photoelectric effect. The photoelectric effect refers to the phenomenon where the electrons of a substance absorb the energy of photons when light is irradiated on it, resulting in corresponding electrical effects.Fiber optic sensorIt is a sensor that converts the state of the object being measured into measurable optical signals. The working principle of a fiber optic sensor is to send the incident light beam from a light source through an optical fiber into a modulator, where it interacts with the measured parameters from the outside, causing the light toopticsThe properties of light, such as intensity, wavelength, frequency, phase, polarization state, etc., undergo changes to become modulated optical signals, which are then sent through optical fibers to optoelectronic devices and demodulated to obtain the measured parameters.

Different performance:

Photoelectric sensor:

① Wide transient response range and strong harmonic measurement capability. The superiority or inferiority of transient characteristics is a judgmentTransformerThe ability to obtain an important parameter for application in the power system, especially the coordination with relay protection action time. Traditional electromagnetic transformers have poor response characteristics to high-frequency signals due to the presence of iron cores, and cannot accurately reflect the transient process on the primary side. The frequency range measured by the photoelectric transformer is mainly determined by the electronic circuit part, and there is no problem of iron core saturation, so it can accurately reflect the transient process on the primary side. Generally, it can be designed up to 0.1Hz to 1MHz, and for special cases, it can be designed up to 200MHz bandpass. The structure of photoelectric sensors can measure harmonics on high-voltage power lines. andElectromagnetic induction transformerIt is difficult to achieve.

② NumberInterfaceStrong communication ability, due toPhotoelectric sensorThe transmitted signal is an optical digital signal, which is easy to interface with communication networks and has no measurement errors during transmission. With the widespread adoption of microcomputer based protection and control equipment, photoelectric transformers can directly provide digital signals to secondary equipment, eliminating the need for converters and A/D sampling in the original protection device, greatly simplifying secondary equipment, and promoting research on new protection principles.

③ Small in size, light in weight, and easy to upgrade, it meets the requirements of miniaturization and compactness of substations. As photoelectric sensors rely on sensing heads and electronic circuits for signal acquisition and processing, their small size and weight are generally below 1000kg, which greatly reduces the footprint of substations and meets the requirements of miniaturization and compactness of substations.

Fiber optic sensor: ① It has the performance of resisting electromagnetic and atomic radiation interference, with fine diameter, soft texture, and light weight mechanical properties ② Insulation, non inductive electrical properties ③ Water resistance, high temperature resistance, corrosion resistance chemical properties, etc. It can play the role of human ears and eyes in areas that are inaccessible to humans or harmful to humans (such as nuclear radiation areas)④ Being able to transcend human physiological boundaries and receive external information that the recipient's senses cannot perceive.

The working principle is different:Firstly, in terms of the working principles of both, the photoelectric sensor operates based on the principle of photoelectric effect, which means that when light is irradiated onto the photoelectric sensor made of semiconductor, it will emit photoelectrons, which can convert light energy into electrical energy. For example, commonly used in light control situationsPhotoresistor, photosensitivediodeAnd photosensitivetriodeAll work is based on this effect. Fiber optic sensors work based on the principle of total reflection of light. The principle of total reflection of light has been studied in high school physics, such as the Snell's law of refraction and reflection, which expresses the principle of light reflection clearly through mathematical relationships. So we use light guidefibreThe transmission characteristics of light can be converted into changes in light properties, such as changing the frequency, wavelength, intensity, and phase of light.

Different materials used for production:The production materials of photoelectric sensors are mainly semiconductor materials or metal materials with photoelectric effects. Fiber optic sensors are composed of glass fibers (mainly quartz glass) with high light transmittance, and their composition is relatively simple.

Different structures:Photoelectric sensorIt is relatively simple, for example, a photodiode consists of pins, a housing, a chip, and a glass spotlight. The structure of fiber optic sensors is relatively complex, and in addition to fibers, there are also some complex peripherals as auxiliary controls.

The measurement range varies:The range measured by photoelectric sensors is relatively limited, generally including light intensity, illuminance, velocity, and strain displacement. The range measured by fiber optic sensors is relatively wide, capable of measuring over 70 physical quantities such as pressure, vibration, velocity, current, temperature, flow rate, magnetic field, etc. Therefore, the potential for the future development of fiber optic sensors is enormous, and it can be said that they are ahead of their competitors.

Different applications:

Photoelectric sensor: using photoelectric technologyelementThere are various types of photoelectric sensors used as sensitive components, with a wide range of applications. According to the output properties of photoelectric sensors, they can be divided into two categories: photoelectric measuring instruments made by converting the measured light into continuously changing photocurrent, which can be used to measure the intensity of light as well as physical quantities such as temperature, transmittance, displacement, and surface state of objects. For example, illuminance meters, photoelectric pyrometers, photoelectric colorimeters, and turbidity meters for measuring light intensity, photoelectric alarms for preventing fires, and automatic detection devices and instruments for checking the diameter, length, ellipticity, and surface roughness of processed parts, all of which use photoelectric elements as sensitive components.

Semiconductor optoelectronic components are not only widely used in civilian industries, but also play an important role in military applications. For example, lead sulfide photoresistors can be used to make infrared night vision devices, infrared cameras, and infrared navigation systems; Convert the measured current into a continuously changing photocurrent. Various photoelectric automatic devices made using the characteristic of "having" or "not having" electrical signal output when illuminated or not illuminated by photoelectric elements. Optoelectronic components used forswitchType photoelectric conversion element. For example, photoelectric input devices for electronic computers, switch type temperature regulating devices, and digital photoelectric speedometers for speed measurement.

Fiber optic sensors: Fiber optic sensors can be embedded in concrete, carbon fiber reinforced plastics, and various composite materials to test stress relaxation, construction stress, and dynamic load stress, in order to evaluate the structural performance of bridges during short-term construction and long-term operation. In the power system, it is necessary to measure parameters such as temperature and current, such as temperature detection inside the stator and rotor of high-voltage transformers and large motors. Due to the susceptibility of electrical sensors to electromagnetic interference, they cannot be used in such situations and can only be usedFiber optic sensor.