Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a micro-grid simulation variable power asynchronous motor load experiment platform, which simulates the electromagnetic transient process of a three-phase asynchronous motor load in the switching process of the micro-grid on and off the grid, comprises the no-load process of the asynchronous motor during actual operation and the starting, running and stopping processes of the asynchronous motor during loading, and can accurately reflect the influence of the actual running process of the whole motor on the transient process of the micro-grid; the motor protection device has an excellent motor protection function, and the motor system is protected by adding a soft start device and overvoltage protection.
A little electric wire netting simulation variable power asynchronous machine load experiment platform includes: the motor is to dragging platform, master control cabinet and adjustable resistance value's resistance cabinet, wherein, the motor include to dragging the platform: asynchronous motor, synchronous generator and shaft coupling, the main control cabinet include: the system comprises a PLC, a touch screen, a dragging motor soft starter and an electric energy quality test instrument;
the PLC is connected with the touch screen through a communication interface, a plurality of output ends of the PLC are respectively connected with the input end of the dragging motor soft starter and the input end of the resistance cabinet, and the electric energy quality test instrument is connected with the main circuit of the control cabinet and respectively measures voltage and current signals;
the output end of the soft starter of the dragging motor is connected with the input end of an asynchronous motor, the asynchronous motor is connected with a synchronous generator through a coupler, and the output end of the synchronous generator is connected with a resistor cabinet.
The apparatus also includes a security system comprising: safety chain latching relay, mushroom head scram switch, PLC controller watchdog and distribution power supply.
The main control cabinet is also provided with a switch, a contactor, a relay and a low-voltage apparatus.
The resistor cabinet comprises a plurality of resistors, and the discharge power interval is set to be 1kW by combining the access resistors through the keys according to the actual power detection requirement.
The invention has the advantages that:
the invention provides a micro-grid simulation variable power asynchronous motor load experiment platform, which is used for setting the load power through a PLC (programmable logic controller) on the basis of simulating no-load and load operation of an asynchronous motor; simple structure, stability, good reliability, convenient use, no complex operation program like the unit, zero-torque (zero-rotation speed) soft start, completely avoiding the impact on the power grid like the unit start, and solving the loading operation only by controlling the touch screen to adjust the resistance, and is extremely convenient to use. It can maintain extremely high stability over the full range of speeds (even at zero speed) and torques.
An embodiment of the present invention will be further described with reference to the accompanying drawings.
In the embodiment of the present invention, as shown in fig. 1, a microgrid analog variable power asynchronous motor load experiment platform, a motor twin-trawling platform, a master control cabinet and a resistance cabinet with an adjustable resistance value, where the motor twin-trawling platform includes: asynchronous motor, synchronous generator and shaft coupling, the main control cabinet include: the system comprises a PLC, a touch screen, a dragging motor soft starter and an electric energy quality test instrument;
in the embodiment of the invention, the soft starter of the dragging motor adopts a JJ1000 model, is used for starting a squirrel-cage asynchronous motor, and can limit starting current and reduce voltage for starting; reducing the impact of starting current on a power grid; the vibration and noise of the equipment are reduced, and the service life of mechanical transmission is prolonged;
in the embodiment of the invention, the asynchronous motor adopts a Y2-180M-2 type dragging motor and is used for dragging a 20kW adjustable load; the addition of the soft start device can reduce the current impact caused by frequent start; after the three-phase asynchronous motor is completely started and after the bypass is softly started, a three-phase asynchronous motor feedback electric energy experiment of micro-grid power-on, power-off and grid-connected and off-grid switching can be carried out;
in the embodiment of the invention, the synchronous generator adopts the synchronous generator set, the performance is stable, the operation is reliable, and the maintenance amount is small;
in the embodiment of the invention, the resistor cabinet comprises a plurality of stainless steel resistors. The power of the resistor under the rated voltage is 1kW, 2kW, 5kW and 10kW respectively. Any power of 1-20 kW can be realized by different combinations, and the minimum resolution is 1 kW;
in the embodiment of the invention, the main control cabinet is provided with: a switch, a contactor, a relay, a low-voltage apparatus, a cabinet heater and illumination; the panel is arranged: instruments, switches, buttons, indicator lights and emergency stop buttons;
in the embodiment of the invention, the PLC adopts Siemens S7-1200 series PLC, is used for controlling the start and stop of a dragging motor, and starts the motor to a rated rotating speed by using a soft starting device; adjusting the rated power of the load, namely adjusting the power of the load by using a controllable resistance box;
in the embodiment of the invention, a main circuit power supply is three-phase 380V alternating current and is taken from a micro-grid and used for driving an asynchronous motor; the load size of the asynchronous motor is determined by the load resistance of the synchronous motor; the control power supply of the main control cabinet is 220V alternating current and is taken from the power distribution cabinet to supply power for the control system and the UPS; the PLC and the control circuit take power through the UPS, and can continuously and stably work in the process of power failure of the microgrid;
in the embodiment of the invention, the PLC is connected with the touch screen through a communication interface, a plurality of output ends of the PLC are respectively connected with the input end of a soft starter of a dragging motor and the input end of a resistance cabinet, and an electric energy quality measuring instrument is connected with a main circuit of a control cabinet and is used for respectively measuring a measuring voltage signal and a measuring current signal; fig. 2 is a schematic circuit diagram of the adjustable power load motor drag test platform according to the present invention;
in an embodiment of the present invention, the apparatus further includes a security system, including: the safety chain self-locking relay, the mushroom head emergency stop switch, the PLC controller watchdog and the power distribution power supply; the safety system is a link formed by connecting elements in series, the safety system is independently controlled and is not restricted by a unit control system, when the unit is activated by pressing down in an emergency stop, the relay cuts off the safety chain self-locking relay, and at the moment, the main power supply of the unit is cut off and needs to be reset by an operator; the unit safety system mainly has the functions: the system is ensured to be in a safe state, and the unit cannot be damaged due to foreseeable faults; the safety system action unit enters an emergency shutdown program, the emergency shutdown program triggers the dragging simulation motor to stop, and the power generation system carries out braking shutdown;
in the embodiment of the present invention, the security system is hierarchical, and generally divided into 2 levels: a primary security system and a secondary security system;
A. secondary security system
The action of the secondary safety system (namely the action of a safety chain self-locking relay triggers the secondary safety system) triggers a quick stop control program; the secondary safety system comprises overheating, power grid overvoltage and undervoltage protection;
B. primary security system
The primary safety system acts (namely the mushroom head emergency stop button acts to trigger the primary safety system) to trigger an emergency stop program; the functions are as follows: and the first-level safety system action unit enters an emergency shutdown program.