This paper focuses on the application of the GGQ series high-voltage solid-state soft starter for 4 agitators at Lantian Paper Industry. Combined with engineering practice, this paper studies and analyzes the technical principle and characteristics of the GGQ series high-voltage solid-state soft starter. Application results show that it can meet customers’ individualized requirements for high-voltage soft starting devices and delivers remarkable economic and social benefits.
Preface
With the rapid economic growth and rapid advancement of science and technology in China, intelligent control systems have found increasingly wide application and are subject to higher performance requirements. As key drive actuators, motors and their control methods attract great attention from technical engineers. The control scheme shall lay a solid foundation for intelligent control and reduce the impact on the power grid during motor start-up.
1. Equipment Overview
After extensive investigation and comparison of cost performance, the management of Yibin Lantian Paper Industry Co., Ltd. finally selected GGQ series high-voltage solid-state soft starters from Dayu Electric Technology Co., Ltd. to implement soft start for the on-site 4 agitator units. Both parties fully understood and analyzed the production process and on-site operating conditions, demonstrated feasible solutions, and jointly formulated the soft start scheme. The main parameters of on-site equipment are as follows: Rated power: 630kW Rated voltage: 10kV Motor load: Agitator
2. Working Principle
The primary main circuit is composed of anti-parallel thyristors connected in series. The protection circuit for thyristor modules consists of RC dynamic voltage equalization circuits, static voltage equalizing resistors, overvoltage protectors and other components. The secondary control circuit adopts a DSP central control system and other electrical components, with a 220V working power supply.
During starter operation, thyristor firing signals are generated by the DSP central control system, amplified by the signal processing unit, and transmitted to high-voltage trigger boards via optical fiber. The trigger boards control the conduction angle of thyristors to achieve a gradual rise of output voltage.
The starter operates according to pre-set start parameters configured for site conditions to gradually raise the motor terminal voltage for smooth motor acceleration. The starting current varies within the preset multiple range. When the motor speed rises to the rated speed and the starting current drops below the rated current, the bypass contactor closes. The starter then switches to standby operation mode, fulfilling the objective of reducing the motor starting current.
3. Design Features of the Soft Starter
Humanized design with user-friendly Chinese HMI (Human-Machine Interface) and multiple combined control operation modes, greatly facilitating user operation.
The system control center adopts Harvard bus and computer fuzzy control technology. The complete unit undergoes high-temperature aging and vibration tests before factory delivery to guarantee reliable product quality.
Starting current, starting time and load voltage can be adjusted according to different on-site loads to reduce start loss. It generates optimal starting torque with the minimum starting current and enables smooth start of the motor and driven load.
Optical fiber communication and voltage isolation technology together with BOD protection trigger circuit are adopted. When one thyristor in the thyristor valve bank fails to conduct, the protection trigger circuit quickly shuts down other firing signals to protect the non-conducting thyristor from breakdown.
An advanced logic control unit realizes innovative programmable logic control and unit protection self-locking upon any fault occurrence.
Equipped with RS‑485 communication function to support bidirectional communication with the host computer for peripheral equipment monitoring.
Featuring reliable performance and simple installation, operation and maintenance.
4. Operating Performance
Field operation results after soft starter commissioning fully satisfy the user’s requirements. Its advantages are summarized below:
- Simple operation and convenient monitoring. All operating data and status of the soft starter, such as input current, output voltage, output current and open/closed loop status, can be displayed on the HMI. The HMI interface is intuitive for operation and observation.
- Reduced maintenance cost. The low starting current imposes no mechanical shock on the unit, extending the service life of the motor and significantly cutting maintenance workload and costs.
- Smooth start without sharp voltage drop, which will not disrupt normal operation of other equipment on the same power grid.
- Savings on capital expenditure for transformer capacity expansion.
5. Concluding Remarks
Since the GGQ series high-voltage solid-state soft starter was put into service, the reliability and safety of the system have been significantly improved, bringing higher operational efficiency and economic benefits to the enterprise.
