Mechanical cabinet with electro-hydraulic proportional servo valve

1. Control technology for electro-hydraulic proportional servo, which ensures high control accuracy and excellent governing performance;

2. Electric operation and manual operation are adopted to realize stable and reliable operation, and prevent the crawl of servomotor; 

3. Unconditional and undisturbed switching between the automatic working condition and electric/manual working condition of electro-hydraulic proportional valve;

4. Hydraulic input and hydraulic feedback are adopted for auxiliary servomotor, which require no bar between electro-hydraulic conversion device and main distributing valve, and ensure simplified structure.

5. Mechanical feedback is canceled.

6. Except for the main distributing valve, all other parts are standard hydraulic parts, which are convenient for hydraulic integration and increase of working oil pressure.

 

  

 

Mechanical cabinet with AC servomotor or stepmotor

1. AC servomotor/stepmotor converter with automatic return to neutral position, which features low rotational inertia, high output torque, no jamming, no oil, and high reliability;

2. Ball screw helical pair is adopted to convert the rotary motion of motor into linear motion, which ensures low starting torque, sophisticated inching at low speed, and precise transmission of motion;

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3. Unconditional/undisturbed switching between automatic operation and manual operation;

4. Single spring is adopted for the return to neutral position; no dead stroke during reciprocating motion, and; accurate and unique neutral position.

5. Mechanical feedback is canceled.

6. The mechanical displacement output of motor converter directly drives the pilot valve of main distributing valve, which requires no bar/oil pipe, but ensures simple structure.

 

 

 

Electrical cabinet

1. On-line test, and timely display of test parameters and graphics;

2. Self-adaptation of control structure; parameter adaptive regulating function; online expert system;

3. Frequency regulation function, power regulation function, and opening regulation function, which can be selected automatically according to different working conditions;

4. Regulating the guide vane opening according to the frequency variation speed of power grid;

5. LCD touch screen is provided with WINDOWS interface to realize test and fault recording;

6. Ensure the fast start, stop, grid connection, and increase/decrease of load for hydroturbine unit;

7. Ensure the stable operation of hydroturbine unit under different working conditions such as no-load, power generation, phase modulation, stop, and manual operation;

8. Ensure the switching between manual operation and automatic operation without impulse;

9. Ensure the hydroturbine unit to automatically follow the system frequency as per the preset frequency difference under non-load working condition;

10. Ensure real-time correction of start opening, no-load opening, and restricted area for adverse working condition; automatic correction of dynamic sensitivity of speed governing system according to working condition, so as to adapt to the sensitivity requirements of different working conditions;

11. Ensure the real-time automatic compensation for mechanical zero drift, and; give corresponding instruction;

12. Limit the opening of electric device, and designate special operators for real-time adjustment;

13. Online real-time correction of artificial frequency dead band (ε) and difference coefficient (bp) is adopted to ensure no disturbance of load;

14. Ensure the local control and upper computer control, and; ensure no disturbance during the load control and switching;

15. Ensure the primary frequency control, so as to meet the requirements of power grid for the frequency modulation operation of hydroturbine unit;

16. Intelligent identification and control for the operation of small network and isolated network;

17. The control strategy with time-varying parameter is adopted to ensure timely identification of no-load, grid connection, isolated operation, and other working conditions with high reliability and stability;

18. Fluted disc or residual voltage is adopted for frequency measurement, so as to realize fast grid connection;

19. Friendly man-machine interface ensures convenient reading and modification of parameters;

20. Realize the communication with upper computer in line with certain communication protocol.

 

Patented technologies

1. Electro-hydraulic proportional follow-up unit for hydroturbine governor (Patent No.: 95 2 38033.1);

2. Hydraulic return to neutral position device for flow feedback in the position of main distributing valve (Patent No.: ZL 2008 2 0191121.9);

3. AC motor servo unit for hydroturbine governor (Patent No.: 98 2 35302.2);

4. Electrical-mechanical converter for automatic return to neutral position of hydroturbine governor (Patent No.: 00420027462.6).

 

Main configuration

Electrical cabinet: PLC/PCC controller, color touch screen, and digital feedback;

Mechanical cabinet: electro-hydraulic proportional servo valve/AC servomotor or stepmotor; high-reliability main distributing valve.

 

 

Standard mechanical-electrical cabinet

Combined or separated cabinet can be designed according to on-site layout requirements.

For the main distributing valve, its nominal diameter is set at 80/100/150/200mm, and its working oil pressure is set at 2.5MPa/4.0MPa/6.3MPa.