The role of capacitive voltage transformer in the master set

Capacitive voltage transformer is a voltage transformer that extracts voltage from series capacitors and transforms through transformer as a voltage source for metering and relay protection, and the capacitive voltage transformer can also couple the carrier frequency to the transmission line for long-distance communication, remote measurement, selective line high-frequency protection, remote control, telex typing, etc. Therefore, compared with conventional electromagnetic voltage transformers, capacitive voltage transformers can prevent ferromagnetic resonance caused by the saturation of the core of the voltage transformer, and have many advantages in economy and safety.

Capacitive voltage transformers are mainly composed of capacitance voltage dividers and medium-voltage transformers. The capacitor voltage divider consists of a porcelain sleeve and a number of series capacitors installed in it, the porcelain sleeve is filled with insulating oil to maintain positive pressure, and a steel bellows are used to balance different environments to maintain oil pressure, and the capacitor voltage divider can be used as a coupling capacitor to connect to the carrier device. The medium-voltage transformer consists of a transformer, a compensating reactor and a damping device installed in a sealed tank, and the space at the top of the tank is filled with nitrogen.

The primary winding is divided into the main winding and the trimming winding, and a low-loss reactor is connected in series between the primary side and the primary winding. Because the nonlinear impedance and inherent capacitance of the capacitive voltage transformer sometimes cause ferromagnetic resonance in the capacitive voltage transformer, the damping device is used to suppress the resonance, the damping device is composed of resistance and reactor, and is connected to the secondary winding, under normal circumstances, the damping device has a high impedance, when the ferromagnetic resonance causes overvoltage, before the medium voltage transformer is affected, the reactor has been saturated with only the resistive load, so that the oscillation energy is quickly reduced.

The voltage in the bus is generally tens of thousands of volts or hundreds of thousands of volts, which cannot be directly measured, and the capacitive transformer can pass through the transformer principle to drop the high voltage to tens or hundreds of volts. There are multiple windings in the transformer, which are used for different purposes according to the different conversion ratios, mainly to measure the voltage and protect the line and related primary equipment. When the voltage in the bus is too high or too low, the data of this change will be transmitted to the protection device through the transformer, and the protection device will then judge which protection action to make according to the set fixed value.

Measure bus voltage for measurement and protection.

Capacitive voltage transformer, the role of intermediate transformer.

1. According to the use, there are two types of voltage transformers for measurement and voltage transformers for protection.

The voltage transformer for measurement is to transmit voltage information to the indicating instrument, the accumulation instrument or other similar instruments; Protective voltage transformers transmit voltage information to protection and control devices.

2. According to the working principle, it is divided into two categories: electromagnetic voltage transformer and capacitive voltage transformer.

The principle of electromagnetic voltage transformer is completely similar to the basic structure and transformer; The capacitive voltage transformer is composed of a capacitor voltage divider, a compensating reactor, an intermediate transformer, a damper and a carrier device protection gap, etc., which is used in the neutral grounding system for voltage measurement, power measurement, relay protection and carrier communication.

3. According to the number of phases, it is divided into two categories: single-phase and three-phase.

The vast majority of products are single-phase, because the capacity of the voltage transformer is small, the volume of the body is not large, and the internal and external insulation requirements between the three-phase high-voltage bushings are difficult to meet, so only 3-15kV products sometimes use three-phase structure.

4. According to the insulating medium, it is divided into three categories: dry type, pouring type and oil immersion type.

Low-voltage transformers that are typically reserved for measurement are dry-type, as are high-voltage or ultra-high-pressure sealed gas-insulated (e.g. sulphur hexafluoride) transformers. The pouring type is suitable for voltage transformers of 35kV and below, and the products above 35kV are oil-immersed type.

5. According to the number of windings, there are two types of windings and multiple windings.

In addition to the primary winding, the voltage transformer dedicated to measurement is powered by only one secondary winding junction measuring instrument. The voltage transformer used in the power system is required to have one or two secondary winding output signals, so the transformer is required to be made into a three-winding or four-winding transformer.

1. The capacitive voltage transformer (CVT) is a voltage mutual distortion sensor for metering and relay protection, and the capacitive voltage transformer can also be coupled to the transmission line for long-distance communication, remote measurement, selective line high-frequency protection, remote control, telex typing, etc.

2. Therefore, compared with the conventional electromagnetic voltage transformer, the capacitive voltage transformer can prevent ferromagnetic resonance caused by the saturation of the core of the voltage transformer, and has many advantages in economy and safety.

3. The capacitive voltage transformer is mainly composed of a capacitive voltage divider and a medium voltage transformer. The capacitor voltage divider consists of a porcelain sleeve and a number of series capacitors installed in it, the porcelain sleeve is filled with insulating oil to maintain positive pressure, and a steel bellows is used to balance different environments to maintain oil pressure, and the capacitance voltage divider can be used as a coupling capacitor to connect to the carrier device.

The capacitive voltage transformer is a voltage transponder divided by a shunt capacitor in the battery room, and the transformer is step-down and isolates the voltage mutual.

Hello, Fanyan works by using the voltage divider characteristics of the capacitor to divide the high-voltage signal into a lower voltage range in order to measure and control. At the same time, it is able to isolate high-voltage signals from low-voltage systems, ensuring safe and reliable measurements. Capacitive voltage transformers are widely used in high-voltage transmission lines, substations and other fields, and are an important measurement and control equipment.

Summary. The capacitance in the high-voltage transformer is used to suppress electromagnetic interference, which can effectively suppress the electromagnetic interference in the high-voltage power grid, so as to ensure the safe operation of the high-voltage power grid. Workaround:

1. First of all, you should check whether the capacitance of the high-voltage transformer is normal, and if the capacitor is damaged, you should replace the new capacitor in time; 2. Secondly, the capacitance capacity of the high-voltage transformer should be checked to see if it is sufficient, and if the capacity is insufficient, the capacitance capacity should be increased in time; 3. Finally, you should check whether the capacitance of the high-voltage transformer is connected correctly, and if the connection is incorrect, the connection method should be corrected in time. In addition, when installing the capacitor of the high-voltage transformer, you should pay attention to the installation position of the capacitor, as well as the installation method of the capacitor to ensure the correct installation of the capacitor.

The capacitor in the high-voltage transformer is used to suppress electromagnetic interference, which can effectively suppress electromagnetic interference in the high-voltage power grid, so as to ensure the safe operation of the high-voltage power grid. Solution: 1. First of all, check whether the capacitance of the high-voltage transformer is normal, if the capacitance is damaged, the new capacitor should be replaced in time; 2. Secondly, the capacitance capacity of the high-voltage Zaoyan transformer should be checked to see if it is sufficient, and if the capacity is insufficient, the capacitance capacity should be increased in time; 3. Finally, you should check whether the capacitance of the high-voltage transformer is connected correctly, and if the connection is incorrect, the connection method should be corrected in time.

In addition, when installing the capacitor of the high-voltage transformer, you should pay attention to the installation position of the capacitor, as well as the installation method of the capacitor to ensure the correct installation of the capacitor.

Excuse me, but please go into more detail?

The capacitor in the high-voltage transformer is used to suppress electromagnetic interference, which can filter out high-frequency electromagnetic waves from the circuit, so as to protect the stability of the circuit. The larger the capacitance of the capacitor, the stronger the ability to suppress electromagnetic interference, but it will also filter out the useful signals in the circuit, so when designing the high-voltage transformer, it is necessary to choose the appropriate capacitance according to the actual situation. The structure of a capacitor is generally composed of two metal sheets and a layer of insulating material, and when current passes through the capacitor, the charge in the capacitor is stored to suppress electromagnetic interference.

The capacitance of a capacitor depends on the size of the capacitor and the thickness of the insulating material, the larger the capacitance of the capacitor, the stronger the ability to suppress electromagnetic interference. In addition, capacitors can also be used to suppress high-frequency noise in circuits, thereby improving the stability of circuits. The larger the capacity of the capacitor, the stronger the ability to suppress the noise per acre, but it will also filter out the useful signals in the circuit, so when designing the high-voltage transformer, it is necessary to choose the appropriate capacitor capacity according to the actual situation.

Answer: Capacitive voltage transformer is developed on the basis of capacitor bushing voltage extraction device, and is generally used in systems of 110 kV and above. Compared with the electromagnetic type, in addition to the role of transformer, its voltage divider capacitor doubles as a coupling capacitor, and at the same time has the advantages of high impact dielectric strength, simple manufacturing, small size, light weight and significant economy.

The main drawback is the mistake.

Poor and transient characteristics are poor, and the output capacity is small.

The working principle of the voltage transformer is the same as that of the general transformer, but there are differences in the structural type, materials used, capacity, error range, etc.

1. Voltage transformer:

A voltage transformer is a type of voltage conversion device. It converts the high voltage to the low voltage so that the change in the high voltage value is reflected with the low voltage value. Therefore, voltage transformers can be used to measure voltages directly with ordinary electrical instruments.

1. Voltage transformer, also known as instrument transformer, is a voltage conversion device;

2. The capacity of the voltage transformer is very small, usually only tens to hundreds of volt ampere;

3. The voltage of the primary side of the voltage transformer is the grid voltage, which is not affected by the secondary load, and the load is constant in most cases;

4. The secondary side load is mainly instrumentation and relay coils, which have a large impedance and very little current through them. If the secondary load is increased indefinitely, the secondary voltage will decrease, resulting in an increase in measurement errors.

5. The voltage transformer is used to indirectly measure the voltage, which can accurately reflect the value of the high-voltage side and ensure the measurement accuracy;

6. No matter how high the primary voltage of the voltage transformer is, the rated voltage of the secondary stage is generally 100V, which makes the manufacturing of measuring instruments and relay voltage coils standardized. Moreover, it ensures the safety of instrument measurement and relay protection work, and also solves the difficulties of insulation and manufacturing process of high-voltage measurement;

7. Voltage transformers are often used in circuits such as measurement and relay protection of transformer and distribution instruments.

2. Transformer:

The transformer is a device that converts AC voltage, current and impedance, when there is AC current in the primary coil, the AC magnetic flux is generated in the iron core (or core), so that the voltage (or current) is induced in the secondary coil, which is used to change the voltage level and load a larger current.

1. There are many types of transformers, which are divided into several categories according to cooling mode, moisture-proof method, core or coil structure, power supply phase, use, etc.;

2. The capacity of the transformer is from small to large, from tens of volt-ampere to tens of megavolt-ampere;

3. The voltage of the primary side of the transformer is greatly affected by the secondary load, and the system voltage will be affected when the load is large;

4. The secondary side load of the transformer is a variety of electrical equipment, which has a large current and a strong load capacity;

5. No matter how high the voltage of the primary side of the transformer is, the secondary voltage can be increased or decreased according to the need;

6. The shape and volume of the transformer are sometimes very large due to the difference in capacity;

7. Transformers are often used in a variety of occasions.

The voltage transformer is mainly used to measure the voltage, mainly to convert the higher voltage into a lower voltage for us to measure, its power is small, and it cannot carry the load.

The role of the incoming (outgoing) voltage transformer:

Monitor the voltage of this line, and apply it to the parallel devices of the system, such as the same time detection, no voltage detection, BZT device, etc.

The role of the bus voltage transformer:

Monitor the voltage and insulation status of the bus, provide voltage loops for protection, automatic devices, instruments and other equipment, and the difference between incoming (outgoing) voltage transformers and bus voltage transformers

The incoming (outgoing) voltage transformer is generally installed with a single set of secondary coils. Whereas, the bus voltage transformer is three-phase and has two sets of secondary coils.