2.4 Control System and Regulation Guarantee of Turbine

2.4.1

The control system of turbine shall have good stability and regulation quality and meet the requirements for stable operation under various operating conditions and the requirements of power grid for frequency and power regulation.

2.4.2

Each unit shall be provided with one set of speed gover ning system composed of governor,oil pressure unit and the auxiliary equipment.

The microcomputer electric hydraulic governor shall be applied.The oil pressure for the governing system shall be 4.0MPa and above.

The control system of turbine should be provided with electric feedback mechanism.

The equipment used for the control system of turbine shall be accurate,safe and reliable,and the pipe connection shall be easy.

2.4.3

The regulation guarantee calculation shall be performed in accordance with the type and parameters of the water conveyance system,the characteristics and operating conditions of the units,the requirements of power grid and the main electrical connections.

Computer simulation calculation shall be applied to the regulation guarantee calculation.Closing law of guide vane and the parameters of the governing system shall be optimized.The stability of governing system shall be analyzed and calculated if necessary.Regulation guarantee calculation shall be performed based on the combinations of different head and various possible operating conditions.

For Kaplan and tubular turbine,the influence of flow inertia moment shall be included in the calculation of speed rising ratio,and the water hammer calculation shall be included in the regulation guarantee calculation.

2.4.4

The guarantee value of the maximum speed rising ratio in the case of load rejection should be determined on the following conditions:

1 It should be less than 50%if the unit capacity accounts for a larger proportion of the total power grid capacity or the unit undertakes frequency regulation.

2 It should be less than 60%if the unit capacity accounts for a small proportion of the total power grid capacity or the unit does not undertake frequency regulation.

3 For tubular units,the maximum speed rising ratio should be less than 65%.

4 For Pelton units,the maximum speed rising ratio should be less than 30%.

2.4.5

The guarantee value of the maximum pressure rising ra tio at the spiral case (in front of the guide vane for a tubular unit) in the case of load rejection should be determined as follows:It should be 70%-100%when the rated head is less than20 m.It should be 70%-50%when the rated head ranges from 20 to 40 m.It should be 50%-30%when the rated head ranges from 40 to 100 m.It should be 30%-25%when the rated head ranges from 100 to 300 m.It should be less than 25%when the rated head is more than 300m.

The guarantee value of the maximum pressure rising ratio shall be determined based on the calculation value with appropriate margin.

2.4.6

In the case that the guarantee value fails to meet Articles2.4.4 and 2.4.5,technical and economic comparisons shall be performed.Such measures as modifying the arrangement or the dimensions of the penstock,increasing the rotational inertia of generator or setting a surge chamber shall be taken to control the rising ratio of pressure and speed.

2.4.7

For the hydropower plants with branch pipes,the maxi mum speed rising ratio of the unit and the maximum pressure rising rate of the spiral case shall be calculated in accordance with the possible unit number of simultaneously rejecting load,taking into account the number of units connected to the main penstock and the mode of main electrical connection.All kinds of possible operating conditions may be combined in the calculation if necessary.

2.4.8

In the case of sudden increase or decrease of unit load,the minimum pressure at the highest point in each section of the entire pressure water conveyance system shall not be less than 0.02MPa.Neither negative pressure nor separation flow should be allowed.The maximum vacuum guaranteed value of the draft tube inlet section shall not be greater than (0.08-E/90000) MPa (E is the turbine setting elevation,in meter) during load rejection.