Supplying 3 speed governors for Ry Ninh Hydropower Plant - Gia Lai

This is truly good news and a technological breakthrough for a highly specialized industry. After its completion, the product was filmed and broadcast on VTV1 and VTV2 by Vietnam Television. The high-pressure oil speed governor uses program control and high-pressure oil control technologies to achieve both control characteristics and other qualities such as standardization, modeling, and modularization. This creates a new structure, ensuring smooth operation, convenient operation, and maintenance. Believe it or not, this type of speed governor is better than those manufactured in China, and its cost is only two-thirds that of those from China.

Basic parameters and operating conditions

1) Basic parameters

Speed ​​governor type: digital control.

Guide vane operating time:

Closing time: 2~7 seconds, adjustable

Opening time is 2-7 seconds, adjustable.

When the unit operates at its rated frequency and rated power, the speed reduction can be adjusted within the range of 0 to 10%.

PID parameters:

Instantaneous deceleration Bt=5～ô150%,

The time delay constant Td = 2～ô25(s), ?

Wing opening range: 0～100%; ?

Frequency dead zone: 0～0.5Hz

2) Operating conditions

Rated operating oil pressure: 16.0 MPa.

The power supply is AC 220V, 50Hz and/or DC 220V. The system can operate normally in the event of any power outage. It can be switched to another machine without disruption.

4. Structural description

The digital speed governor conforms to IEC60308, the test conditions for hydraulic turbine speed governors. Besides the main digital controller, the system is also equipped with an emergency stop solenoid valve and a manual operating device, used for manual control in case the main controller fails.

 (1) Description of structure:

The digital speed governor is a parallel-type PID controller. It functions to control power, speed, vane opening, automatically adjusts to grid frequency, self-diagnoses and corrects errors, and ensures stability. It is also equipped with standard protocols and hardware-software interfaces for communication with a computer-based supervisory control system.

            (2) Structural arrangement

The hydraulic section of the speed governor and the digital control cabinet are integrated together. The gauges and control devices are mounted on the front of the cabinet for easy observation and operation.

(3). The contract terms do not contain any special provisions but only provide a complete speed control coefficient with the necessary functions and equipment and components such as computers and peripherals, control equipment, auxiliary relays, and necessary sensors, all of which are supplied by our side.

(4) The dimensions of the speed governor connection with the turbine include the servermotor stroke, the dimensions of the center of the adjustment ring to the plane of the servermotor base, the dimensions of the connecting shaft… as proposed by the turbine manufacturer.

(5) The speed regulator can be switched manually, with manual on/off mode.

* Display unit

5. Speed ​​of the speed governor

The speed control system must have sufficient power; when the pressure of the pressurized oil device is at its lowest level, the counter-torque acting on the guide vanes can operate the guide vane motor to close for its entire stroke.

6. Effective

(1) Stability When operating at no load and operating with the power grid, the speed control system can stably control the rotational speed of the generator set.

 If the turbine's hydraulic system and water conduction are stable, the governor is considered stable when the following conditions are met.

When the generator is running at idle with a deviation coefficient of 2% or more, the speed governor must still ensure that the fluctuation does not exceed 0.1% of the rated rotational speed.

When the electrical equipment is operating and switching to a backup power source or switching manually/automatically, the change in the guide vane server motor's travel should not exceed ± 1% of the total travel.

 (2) Static characteristics:

The static characteristic curve is almost a straight line, with the maximum nonlinearity not exceeding 5%.

(3) Dead zone.

At rated rotational speed and any vane opening, the servomotor's rotational speed dead zone shall not exceed 0.04% of the rated rotational speed.

(4) Dynamic characteristics

After cutting off 100% of the rated load, during speed changes, the peak of the waveform at 3% or more of the rated speed must not exceed twice.

After cutting 100% of the rated load, the time interval from when the servomotor begins moving in the opening direction for the first time until the rotational speed fluctuation of the unit does not exceed ±0.5% must not be greater than 40 seconds.

 (5) Catch up with the frequency

To shorten the synchronization time, the speed governor has a frequency catch-up mechanism, which has a fine adjustment function, gradually bringing the frequency difference between the generator unit and the grid frequency to zero.

(7) When operating the speed governor manually, there is an opening catch-up mechanism to ensure that when necessary the generator can quickly switch to automatic mode without oscillation.

 (8) Speed ​​and power adjustment range

When the generator is running idle, the speed control mechanism can adjust the generator's rotational speed to 90% - 100% of the rated speed. When the generator is running idle with a rotational speed deviation of 0, the manual or electric speed control mechanism allows for synchronization at 90% - 100% of the rated speed. When the rotational speed deviation is 5%, the speed control mechanism can reduce the power output and fully open the turbine to 0% for a period of no less than 20 seconds and no more than 40 seconds.

 (9) The speed governor is resistant to oil contamination. The temperature fluctuation of the electric part of the speed governor, taken into account the relative value of the rotation, does not exceed 0.01%.

7. Safety protection devices

 (1) Fault protection: When faults or power outages occur, in addition to the machine stopping circuit and the mechanism limiting the opening of the guide vanes, the speed governor must keep the guide vanes in the position before the fault. For major faults, the unit must stop, the indicator lights in the electrical cabinet must indicate the fault, and the speed governor's unit signal contacts become inoperative.

 (2) Segmented closing: The speed control system can, based on user requirements, have the function of closing the segmented guide vanes without adjustment. This device has been implemented through the operation of similar turbines. The closing time with the corresponding guide vane opening will be adjusted after optimal calculation. All electromechanical and piping parts of the device are supplied by us. This device prioritizes the use of hydraulic mechanical structure.