What is a transformer?

Question 1: What is a transformer? A transformer is a device that converts voltage or current in proportion. The function of transformer is to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 10A, both refer to rated value) in proportion, so as to realize the standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment. Transformers can also be used to isolate high-voltage systems to ensure the safety of personnel and equipment.

Question 2: What is the function of mutual inductor? Transformers include voltage transformers and current transformers.

Voltage transformer is a voltage conversion device with dual functions of voltage conversion and isolation. It converts the high voltage of high voltage circuit or low voltage circuit into low voltage (generally 100V) and supplies it to instruments and relay protection devices for measurement, measurement and protection. Current transformer is a current conversion device with dual functions of current conversion and isolation. It converts a large current in a high-voltage circuit or a low-voltage circuit into a small current (usually 5A), which is supplied to instruments and relay protection devices for measurement, measurement and protection. In actual measurement, in order to better match the measuring range of the instrument, there are also transformers that convert small current below 5A into large current (5A).

Question 3: What is a transformer and what is it used for? 1. Turn the high voltage and large current of the primary circuit into the standard value of the secondary circuit.

Generally, the rated voltage of the secondary winding of voltage transformer is 100V or v, and the rated current of the secondary winding of current transformer is generally 5A or1a..

2. The low-voltage secondary system is electrically isolated from the high-voltage primary system, and the secondary side of the transformer is grounded to ensure personal and equipment safety.

The purpose of grounding the secondary winding of transformer is to reduce the ground potential of the secondary system when the primary and secondary windings break down. The smaller the grounding resistance, the lower the low potential, thus ensuring personal safety, so it is called protective grounding.

After the primary winding of the three-phase voltage transformer is connected in star shape, the neutral point is grounded. Its purpose is to make each phase of the primary winding and the secondary winding reflect the grounding voltage of each phase of the power grid, thus reflecting the grounding short circuit fault. Therefore, this grounding is called working grounding.

3. Obtain zero-sequence current and voltage components for use by relay protection devices responding to ground faults.

Branch zero sequence current, so the secondary winding of the three-phase current transformer is connected in parallel, so that the total output current is the sum of the three-phase currents, that is, the zero sequence current of the primary power grid is obtained. If the three phases of a primary circuit (such as a cable circuit) pass through an iron core, zero-sequence current is output around the secondary winding of the iron core.

Question 4: What does current transformer mean? Definition of current transformer:

The principle of current transformer is based on electromagnetic induction principle. The current transformer consists of a closed iron core and a winding. Its primary winding has fewer turns and is connected in series with the measured current, so all the current of the line often flows, and its secondary winding has more turns and is connected in series with measuring instruments and protection circuits. When the current transformer works, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and the protection circuit is very small, and the working state of the current transformer is close to short circuit.

Functions and uses:

In power generation, transformation, transmission, distribution and power lines, the current varies greatly, ranging from several amperes to tens of thousands of amperes. In order to facilitate measurement, protection and control, it needs to be converted into relatively uniform current, and the voltage on the line is generally high, so direct measurement is very dangerous. Current transformer plays the role of current conversion and electrical isolation.

Question 5: What is the function of mutual inductor? What kind? 1) cooperate with the measuring instrument to measure the voltage, current and energy of the line.

2) cooperate with relay to protect power system and equipment from overvoltage, overcurrent, overload and single-phase grounding;

3) isolate the high voltage of measuring instruments, relay protection devices and lines to ensure the safety of operators and equipment;

Question 6: What is a current transformer? Main purpose? The principle of current transformer is based on electromagnetic induction principle. The current transformer consists of a closed iron core and a winding. Its primary winding has fewer turns and is connected in series with the measured current, so all the current of the line often flows, and its secondary winding has more turns and is connected in series with measuring instruments and protection circuits. When the current transformer works, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and the protection circuit is very small, and the working state of the current transformer is close to short circuit.

Question 7: What material is Transformers made of? There are many kinds of transformers. At present, 10-35KV current-voltage transformer is generally dry, made of epoxy resin mixture, and consists of primary coil (made of copper tape or conductive rod) and secondary coil wound on magnetic silicon steel sheet. The specific principle of substation can be found online or bought a book on transformer principle. Generally, the outer surface of a transformer above 35KV is composed of a porcelain sleeve and a metal cabinet, and the internal insulation is made of various materials such as oil stroke insulation or sulfur hexafluoride gas insulation. The principle of power conversion is the same.

Question 8: How to install the transformer and what role does it play? The function of voltage transformer is to convert high voltage into standard secondary voltage of 100V or lower for protection, measurement and instrumentation. At the same time, the use of voltage transformer can isolate high voltage from electrical workers. Although voltage transformer is also a device that works according to the principle of electromagnetic induction, its electromagnetic structure relationship is just the opposite compared with current transformer. The secondary circuit of voltage transformer is a high impedance circuit, and the secondary current is determined by the impedance of the circuit. When the impedance of the secondary load decreases, the secondary current increases, which makes the primary current automatically increase by one component to meet the electromagnetic balance relationship between the primary side and the secondary side. It can be said that voltage transformer is a special transformer with limited structure and use form.

The working principle of electromagnetic induction voltage transformer is the same as that of transformer, and its basic structure is also iron core and primary and secondary windings. Its characteristics are small and relatively constant capacity, and it is close to no-load state during normal operation. The impedance of the voltage transformer itself is very small. Once the secondary side is short-circuited, the current will increase sharply and burn the coil. Therefore, the primary side of the voltage transformer is connected with a fuse, and the secondary side is reliably grounded to avoid personal and equipment accidents caused by high potential on the secondary side when the insulation of the primary side and the secondary side is damaged. The measuring voltage transformer is generally made of single-phase and double-coil structure, and its primary voltage is the measured voltage, which can be used in single phase or connected to two sets of three-phase in V-V shape. The primary side of the voltage transformer used in the laboratory is usually multi-tapped to meet the needs of measuring different voltages. The voltage transformer used for grounding protection also has a third coil, which is called a three-coil voltage transformer. The third coil of the three phases is connected into an open triangle, and the two leading ends of the open triangle are connected with the voltage coil of the grounding protection relay. During normal operation, the three-phase voltage of the power system is symmetrical, and the sum of the three-phase induced electromotive force on the third coil is zero. Once the single-phase grounding occurs, the neutral point will be displaced, and zero-sequence voltage will appear between the terminals of the open triangle to make the relay act, thus protecting the power system. When zero-sequence voltage appears in the coil, zero-sequence magnetic flux will appear in the corresponding iron core. Therefore, this three-phase voltage transformer adopts side yoke iron core or three single-phase voltage transformers. For this kind of transformer, the accuracy of the tertiary coil is not high, but it is required to have certain over-excitation characteristics.

Question 9: What's the difference between a transformer and a sensor? The national standard GB7665-87 defines a sensor as "a device or equipment that can sense a specified measured signal and convert it into a usable signal according to certain rules, usually consisting of a sensitive element and a conversion element". Sensor is a kind of detection device that can sense the measured information, and can convert the sensed information into electrical signals or other required forms of information output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control. This is the first step to realize automatic detection and automatic control.

A transformer is a device that converts voltage or current in proportion. The function of transformer is to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 10A, both refer to rated value) in proportion, so as to realize the standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment.

Transformers are only used in the power field, including voltage transformers and current transformers. Sensors are used in all aspects. Maybe you have him in your mobile phone: the keyboard light doesn't light up in strong light, but it will light up in dark places. This is an optical sensor.

Question 10: What is a transformer? A transformer is a device that converts voltage or current in proportion. The function of transformer is to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 10A, both refer to rated value) in proportion, so as to realize the standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment. Transformers can also be used to isolate high-voltage systems to ensure the safety of personnel and equipment.