Section 2 Turbine/Pump-Turbine

Article 84. Hydraulic turbine system operation test

1.Wicket gate operation test

(1)By opening and closing operation, servomotor pressure must be measured by pressure gauge. Closing and opening time of servomotor stroke and closing property of servomotor must be measured at dry condition.

The both opening and closing times ofthe wicket gate operation device must beset out by the distribution valve or load limiter, etc,.

Opening and closing pressure of servomotor must be constant except at start and stop motions.

Opening and closing time of servomotor stroke and closing characteristic must be kept within design value.

(2)The servomotor stroke must be adjusted to a closing characteristic and opening and closing time of the auxiliary and main servomotors must be measured.

The characteristic of nonlinear closing of the main servomotor must be adjusted and measured by oscilloscope with stopwatch.

Figure 84-1 Example of Characteristic of nonlinear closing (Servomotor)

Table 84-1 Nonlinear closing time and Opening time

2.Governor control characteristic test

(1)Input voltage and current of control unit must be set at the design value and change their values between the parameters of maximum head to minimum head.

100

(2)The governor control characteristic test must be carried out for all devices and equipment to be applied to the governor; e.g. immovable area, adjusting area of speed, adjusting area of permanent speed droop, detecting device of revolving speed, etc,

3.As the result, the characteristics of no-load opening, opening position of servomotor and load limiter depending on each output must be confirmed and kept within design value.

Article 85. Inlet valve operation test

1. Inlet valve sealing test

After installation of Inlet valve, sealing mechanism of upper stream side and down stream side must be confirmed for obtaining proper opening and closing pressureby using oscilloscope or pressure meter.

As the result, sealing mechanism must be operated without abnormality under the design value.

2. Inlet valve opening and closing test

Opening and closing pressureand operating time must be measured using pressure meter /gauge or oscilloscope with stopwatch.

This test must be performed after and before water injection in penstock.

As the result of test, operation mechanism must be movedsmoothly at full stroke under the design value.

3. Measuring leakage water of inlet valve

After sealing of upper and lower side, the leakage water from drainage pipe of upstream side must be measured. The lower stream side, the leakage water must be measured at drainage pipe on casing. The leakage water must be checked with measuring time.

4. As the result of measurement, the leakage water quantity must be kept within design value. * Measuring device: 1. pressure meter or oscilloscope with stopwatch.

2. Water measuring tank for drainage water.

Section 3 Auxiliary Equipment of Turbine/Generator

Article 86. Auxiliary equipment operation test

1.Auxiliary equipments are composedof oil supply system,water supply system andair supply system.

For smooth operation of generator, hydraulic turbine, following tests must be executed;

(1)Non-destructive test, hydraulic pressure test or other necessary test,

(2)Continuous operation test for pumping motors and compressor,

(3)Confirmation of safety valve operation,

(4)Confirmation of air tank and oil pressure tank capacity,

(5)Operational tests of mechanical brakes and rotor jacking device,

(6)Functional tests of electrical protection system; i.e. all alarm and tripping signals,

(7)Functional tests of turbine generator control system,

101

(8)Functional tests of air cooling system,

(9)Check of calibration and correct operation of all limit switches, thermometers, flow relays, pressure switches, switchgear mechanisms and other devices,

(10)Ancillary power system,

(11)Telecommunication system.

2.As the result of the inspection at operation test, capacity for each auxiliary equipment and the performance must satisfy the design value.

Article 86-a1 Neutral grounding equipment test

1.The neutral point of the generator must be earthed through following two (2) methods normally.

(1)Single phase pole transformer grounding scheme,

(2)Resistance grounding scheme.

2.The following items must be tested for each grounding scheme.

(1)Single phase pole transformer grounding scheme.

1)Characteristic test of Neutral grounding transformer (NGT): Dry type epoxy resin molded transformer of self-cooled type

2)Characteristic test of protection equipment with secondary resistance,

(2)Resistance grounding scheme.

1)Characteristic test of Neutral grounding resistor (NGR),

2)Characteristic test of protection equipment with current transformer,

(Reference Documents)

- IEC60076-11 Power Transformer

Article 86-a2 Fire extinguisher system test

1.A sufficient number of smoke and temperature detectors must be assembled on the both end of winding of generator. The fire extinguisher system must give a alarm when the temperature of winding exceed 150°C and indicate its location. When the temperature of winding exceed 200°C, the system gives alarm again, and the signal can connect to unit shutdown circuit with operating differential relay (87) of generator.

2.Fire extinguisher system for generator is two (2) methods, e.g. Water and Gas (CO2) supply systems.

Section 4 Power Plant Equipment (PPE)

Article 87-a1 Operation control system test

< The provisions of this article must refer to Article40 of Section 4 of Chapter 4 in Part 2.> (Refer to Vol.4 Part 4, Chapter 4 Article 91 Automatic start and stop tests)

(Refer to Vol.4 Part 4, Chapter 4 Article 93 Changeable operation mode)

102

Article 87-a2 Protective device test

< The provisions of this article must refer to Article 40 of Section 4 of Chapter 4 in Part 2.>

Article 87-a3 Switchgear operation test

< The provisions of this article must refer to Article 36, Section 4 in Part 2.>

Article 87-a4 Main circuit test of generator

< The provisions of this article must refer to Article 28~30, 34 and 64, Section 3 in Part 2.>

(Additional Guideline for Main circuit of generator (Part 3 Hydro power plant)

1.The main circuit between generator and step-up/main transformer for the generator/generatormotor is applied two (2) methods normally, such as, isled/insulated phase bus (IPB) or power cable (Oil field cable (OF cable) or Cross-linked polyethylene (XLPE) insulated vinyl sheath cable (CV cable)) with circuit breaker (CB), disconnecting switch (DS), voltage transformer (VT), current transformer (CT), etc,.

2.Closed bus-bar is separated IPB type for high voltage, large current and bus-duct type of phase division for small current.

(1)Main circuit test of IPB type

1)Visual inspection for bus-ducts, conductors, supporting insulators, earth bar of bus-ducts, etc.,

2)Cleaning for supporting insulators, bus-ducts, etc.,

3)Measurement of insulation resistance,

4)Withstand voltage test (with generator.)

Article 87-a5 Overhead traveling crane

1.Running-in-trails with load and without load including inching operation test for the hoisting and lowering direction and/or the vertical movement;

(1)Deflection of the main bridge girders: Test load at 125% of rated capacity. (Deflection of the bridge girders must be measured and compared with the guaranteed value and rated load test must be performed for the purpose of checking the safety only),

(2)Brake operation tests with maintaining load,

2.All electrical measurements must be performed during operation tests mentioned above.

(Other elevating machinery may be same test as above, mostly.)

Article 87-a6 Main transformer test

1.Main transformer for the pumped storage power plant is applied in the both ways for the step-up and step-down voltages of the generating operation and pumping operation (motoring mode) respectively, with tap-changer equipment installed high-voltage side.

<The provisions of this article must refer to Article 27 in Part 2.>

103

Article 87-a7 High voltage power cable /bus duct test

< The provisions of this article must refer to Article 64, Section 3, Chapter 6 in Part 2.>

Article 87-a8 Switchyard equipment test

< The provisions of this article must refer to Section 4 Chapters 4, 5 and 6 in Part 2.>

Article 87-a9 Fire extinguisher system test

1.Automatic fire alarm system and fighting system

In case of the fire extinguisher system with automatic water spray system installed in the powerhouse, the inspection or test must be executed for the following major components;

(1)Fire alarm sensors, e.g. temperature detectors, smoke detectors, smoke beam detectors, etc.,

(2)Strainers for water spray,

(3)Control cabinets for the automatic water spray system,

(4)Auto water spray system, etc.

2.Fire hose reel system

The water source from the water supply pipes must be connected to the fire nose reel boxes and water supply fountains of the powerhouse.

(1)Fire house reel boxes,

(2)Fire fighting fountains,

(3)Nozzle.

3.Potable and mobile extinguishers

The required number of potable and mobile fire extinguisher with carbon dioxide, powder, etc., must be provided in the powerhouse.

The carbon dioxide fire extinguishers must be in accordance with NFPA 12.

4.Fire barrier doors

The purpose of fire barriers must be to limit the extent of the fire associated smoke and gasses.

5.Corrosion protection and painting

The corrosion protection of the equipment i.e. surface preparation and paint application must be carried out.

6.Site tests

The site tests must be executed two (2) stages, normally, as following;

(1)Preliminary tests

(2)Commissioning tests

(Reference Documents)

-BS3116-4 British Standard,

-The Codes 70 to 72, 90A of the National Fire Protection Association (NFPA) USA

-TCVN 5738: 1993 and TCVN 2622: 1995

104