Thyristor solid medium voltage soft starter

Thyristor solid medium voltage soft starter

I. Overview

In our country's coal mine, petroleum, chemical industry, steel, power generation, water supply, cement building materials and other fields, there are a large number of 3KV, 6KV, 10KV and other voltage levels of medium and high voltage AC asynchronous motors. A large part of them do not require speed regulation, but need to solve the starting problem of these high-voltage large motors.

Direct starting of high-power AC motors will cause a series of problems

Electrical problems:

It can reach 5-7 times the rated current when starting, causing the motor windings to overheat due to the current, thereby accelerating the aging of its insulation and causing voltage fluctuations in the power supply network. When the voltage is less than or equal to 0.85UN, it will affect the normal use of other equipment.

Mechanical problems:

Excessive starting torque produces mechanical shock, which causes a large impact on the driven equipment, shortens the service life, and affects accuracy. Such as damage to the coupling, torn belt, etc. Causes abnormal wear and impact of mechanical transmission parts, accelerates aging and shortens life.

In order to solve the above problems, a soft starter should be used to control the starting current and starting torque.

The soft starters currently used are: star/angle change soft start, autotransformer soft start, reactor soft start, hydraulic resistance soft start, magnetic control soft start and thyristor soft start.

TGQ1 series medium and high voltage soft starters are equipment used to start high voltage (3000V—10000V) AC asynchronous motors. Its main composition is a three-phase parallel thyristor assembly and its electronic control device connected between the power supply and the controlled motor. When the motor is started, the conduction angle of the thyristor is controlled according to a certain rule (such as constant current or a certain voltage change rate), and the voltage value of the input motor is continuously changed to the full voltage, which limits the current during the motor starting process .

3KV-10KV motor starting in advanced foreign countries mainly adopts thyristor voltage regulating soft start. The thyristor voltage regulating soft starter conforms to the development trend of science and technology, and will surely become the mainstream product in the field of medium and high voltage soft start.

The thyristor voltage regulating soft starter is a product of the combination of modern computer control technology and power electronic technology. The starting current, starting time, stopping time, current limit and various protection values ​​can be set according to different application conditions. Features such as smooth starting and maintenance-free make it have superiority that other soft starters cannot match.

3KV-10KV motor starting in advanced foreign countries mainly adopts thyristor voltage regulating soft starter. More than 90% of domestic low-voltage 380V motors have used thyristor voltage-regulating soft starters.

The thyristor voltage regulating soft starter conforms to the development trend of science and technology, and will surely become the mainstream product in the field of medium and high voltage soft starters in my country.

Second, the advantages of thyristor high-voltage soft starter

1. It is applicable to a wide range of voltage and power, and can be used with motors of 6kV-10kV/600kW-22MW;

2. It has soft start and soft stop functions to fully guarantee the safe start and stop of the system;

3. When the motor starts, the current smoothly rises from zero to the set value, and the starting is stable;

4. Mechanical aspects: reduce mechanical impact, prevent overpressure and water hammer effects, and extend the service life of the transmission mechanism;

5. Electrical aspects: reduce the starting impulse current by half, extend the service life of the motor, reduce the voltage fluctuation of the power grid and the impact on other power users;

6. It can realize soft stop, which can eliminate the impact and damage to some equipment caused by sudden stop;

7. Comprehensive protection functions to prevent personal safety accidents;

8. High degree of intelligence, simple setting and operation;

9. Small size, saving infrastructure investment;

10. Reduce the capacity of power supply equipment and save project investment costs. 3. Mainly applicable to:

The functional parameters of the TGQ-1 soft starter can be set on-site according to the load performance characteristics. Therefore, it can be used for squirrel cage asynchronous motors or synchronous motors produced by various manufacturers. Together with various high-voltage motors with good performance, they can form a mutually optimal Cooperative high-performance drive unit.

It can be widely used in large-scale steel, petrochemical, large-scale coal mines, sewage treatment plants, power plants, pumps and fans, mining compressors, mills, conveyor belts and other equipment.

4. The system voltage and motor power range of the high-voltage soft starter:

Power supply voltage——6kV～10kV Motor power——660kW～22MW

5. Protection of soft starter

The soft starter has the following protection functions:

(1) Thyristor failure Figure 3 Xiangtan Iron and Steel Group uses 11 TGQ-1000kW/10kv soft starters at one time. This is an application site

(2) Phase failure protection

(3) Three-phase unbalance

(4) Starting overcurrent

(5) Running overcurrent

(6) Loss of pressure failure

(7) Reverse sequence failure

(8) Starting overtime

(9) Short-circuit fault protection

(10) Contactor failure protection