Publish Time: 2022-07-29 Origin: Site
Motor parameters:
Motor 1: power 1000kW; current 57.4A; voltage 10kV; power factor 0.9.
Motor 2: power 1600kW; current 110.2A; voltage 10kV; power factor 0.877.
Pump parameters:
Flow: 3100m⊃3;/h;
Hydraulic head pressure: 96m;
Load start and stop control requirements: operate according to the water level.
Background of Automation transformation
The pressure regulation of the boiler feed pump system of the thermal power plant is regulated by the electric regulating valve on the outlet side, not according to the actual water consumption. Therefore, a large amount of water resources and power resources are wasted, and it has great energy saving potential. The motor of this system is controlled by 10kV vacuum circuit breaker to start and stop, and it does not have the function of soft start, which causes serious wear to the transmission system and low power factor of the motor. Every time the motor starts, the starting current is as high as 4~7 times of the rated current, which greatly shortens the service life of the stator winding. Due to the large mechanical impact and severe vibration, the bearings, balance discs and balance rings need to be replaced frequently, resulting in expensive repair costs every year.
Solution
The application of soft starter can solve the above problems in motor starting.
The soft starter integrates motor soft start, soft stop and multi-function protection. In the heating industry, soft starters can be used in various applications of squirrel-cage asynchronous motors that do not require speed regulation, especially suitable for various pump loads or fan loads that require soft start and soft stop.
In practical applications, the soft starter can not only be used to control a single motor, but also can control multiple motors when used in conjunction with a PLC, which is economical and practical.
CMV series high-voltage soft-start device is suitable for start-stop control and protection of squirrel-cage asynchronous and synchronous motors. The device is composed of multiple thyristors in series and parallel, which can meet different current and voltage requirements.
✔ Easy to install and use. Before high-voltage operation, it is allowed to use low-voltage to conduct electrical tests on the entire system to ensure safety;
✔ A vacuum contactor is installed inside, in special cases, the motor can be started directly to ensure the continuity of production and improve efficiency;
✔ Thyristor is used as the main circuit component, with multiple protection functions;
✔ 32-bit ARM micro-core controller, real-time efficient, reliable and stable central control function;
✔ RS-485 communication interface, can communicate with the centralized control center or the host computer; (usually industrial computer, workstation, touch screen as the host computer, communication control PLC, single chip and so on as the lower computer, so as to control the relevant equipment components and drive devices.)
✔ Compact structure, separate design of high pressure part and low pressure part;
✔ Reasonable layout, anti-pollution, modular design for easy replacement and maintenance;
✔ Good cost performance;
✔ 3 kinds of start and stop control modes: local control, remote control and DCS control.
Protection of the built-in motor on the soft starter:
Phase loss protection, phase sequence protection, starting overcurrent protection, running overload protection and motor can not start protection for a long time. When the protection function of the soft starter is activated, its control panel will directly display the fault signal (the digital can display the fault code).
Adjustable control parameters on the soft starter panel:
Soft-start time, start-up initial voltage, start-up current limit, soft-stop time, soft-stop step-down voltage (pump stop function), pulsating kick start (for sudden load) functions. In actual operation, these parameters can be set or selected according to the specific conditions of the equipment motor in the project and the description of the soft starter.
The soft starter can also have a built-in one-to-multiple special program controller option, which is installed inside the soft starter to realize time control, interlocking, and interlocking functions, and can control the separate starting of multiple motors. The motors can be started arbitrarily in no particular order, automatically preventing more than two motors from starting at the same time. After one motor is started, the delay time has not expired, and other motors cannot be started.
Classified by motor load and speed changes, soft start is often used to:
Equipment with large load changes and no speed changes:
Such as port belt conveyors, coal mine belt conveyors, cement belt conveyor equipment, escalators, elevators without inverters, steel rolling equipment, various industrial conveying machinery, etc.
Variable load equipment:
Such as central air conditioners, hexagonal machine tools, mills, grinding machines, forming machines, punching machines, polishing machines, hanging machines, presses, cutting machines, compressors, oil well pumping units, electric sewing machines, food mixers, injection molding machines, Forging machine, plate machine concrete forming machine, rubber forming machine, chemical industry equipment, agricultural equipment, textile machinery, paper making equipment, industrial machinery, food and other heavy industrial machinery.
In terms of efficiency, thermal power plants can improve the efficiency of power generation through the application of electrical automation technology. On the basis of not making major changes to the existing power grid and units, the optimization effect of electrical automation technology can be used to tap the potential and efficiency of thermal power plants.
In terms of cost, the application of electrical automation technology in a thermal power plant can reduce the energy consumption of the thermal power plant, and further reduce the cost of the thermal power plant while ensuring the power generation efficiency of the thermal power plant.
In addition, electrical automation technology has the function of optimizing resource allocation. The electrical automation technology can realize the optimization and adjustment of the main links of the thermal power plant and realize the rationalization of the allocation of resources. The effective use of electrical automation technology can reduce the failure rate of thermal power plant equipment operation and improve the quality of thermal power plant maintenance and repair work.