Table of Contents
- General
- Drawings and Data
- Operation
- Generator
- Construction of Control and Distribution Board
- Busbar System
- Wiring and Marking
- Quick Open Valve
- Baseplates
- Tests
- Instruction Plates
- List of Recommended Suppliers
- Turbine
- Oil Cooler
- Starting of Turbine
- Starting of Motors
- Adjustment of Bypass Valve
- Choke
- Power Transformer
- Rotor and Vibrations
1. General
1.1 Description
This specification covers the minimum technical requirements for a (backpressure condensing/exhaust to atmosphere) steam turbine driven no break generator.
The unit shall include, but is not limited to: generator, coupling, turbine, cooler, piping, valves, governor, control and distribution board, including all control devices, signals, alarm, electric and mechanical protection devices.
Turbine and generator shall both run at the same speed and shall be directly coupled, unless otherwise specification in the requisition.
The unit shall be suitable for indoor use in a refinery atmosphere and maximum ambient temperature of 50oC (ambient temperature) or outdoor if specified in the requisition. Besides any special requirements laid down in this specification the general requirements for steam turbine will be covered by the requisition.
1.2 Standards
Turbine generator shall be in accordance with national standards as stated in the requisition, the requirements of power supplier and all other regulations for this type of equipment.
Company’s terms and conditions applicable for field labor will apply in case of erection at site.
1.3 Installation at Site
Where site erection is part of vendor’s supply the following will be supplied and installed by others.
1.3.1 Power cables and the connection of power cables to vendor’s equipment, except excitation and turbine control cables. These cables shall be connected by vendor.
1.3.2 Civil and piping provisions outside vendor’s equipment. However, this applies only in case the necessary information has been transmitted by vendor to Company within 8 weeks after placing of the order.
Provisions required at a later date will be vendor responsibility.
1.4 Work to Be Done by Vendor
All work including supervision required by installation, testing and proofoperating of the whole unit at site shall be carried out by vendor unless it is stated specifically that it will be done by others.
Testing of the whole unit under normal operating conditions not at Client’s property. Normal operating conditions means:
a. Normal steam pressure (pressure stated in the requisition)
b. Normal steam temperature (temperature stated in the requisition)
c. Normal electricity supply
d. Full load conditions of turbinegenerator unit
e. Ambient temperature as stated in the requisition.
1.5 Transport and Off Loading Facilities on Site
1.5.1 In general, cranes are available on site, which vendor may use for his own account and under his own responsibility. Availability of cranes and/or other necessary equipment has to be checked with the construction superintendent or his representative on site at least 1 week before arrival of equipment.
1.5.2 Transport from car, train or boat to the relevant building will be carried out:
a. By vendor or by subcontractor of vendor with or without vendor’s supervision
b. By others if specified in the requisition.
In all cases, transport, temporary protection of equipment (in case unloading on the same day is impossible or because of weather conditions) and/or other handling procedures will happen under vendor’s full responsibility. Part of equipment damaged during loading, unloading and transport will be replaced immediately free of charge and without any time delay to the final delivery time stated in the order.
In no way it is possible for vendor to withdraw his responsibility for transport and/or storage of his equipment till final written take over by the field representative.
1.6 Conflicting Requirements
In case of conflict between the conditions and documents mentioned above or between these and this specification the severest requirements will govern.
Purchaser is not committed to check vendor’s documents like quotations, order confirmations, drawings, etc. Purchaser will review them.
It will remain vendor’s responsibility to make the turbine generator set in accordance with specification in a fully functional and workmanlike manner.
A deviation from this specification is only acceptable in case vendor has specified in his quotation under the heading “deviations from specification” the requirements he cannot meet and Company has accepted this deviation in writing before ordering or in the order.
Failure to do so will be interpreted by purchaser as confirmation that manufacturer complies fully with this specification.
2. Drawings and Data
Drawings and other technical data shall be furnished in quantities as specified in the invitation for bids, respectively in the order.
2.1 Drawings and Data to Be Furnished with the Quotation
Vendor has to furnish following drawings and data:
2.1.1 One line diagram of the system, showing the main components and their ratings.
2.1.2 Outline drawings showing overall dimensions and approximate total weight.
2.1.3 Drawings showing miscellaneous components and location of cable boxes, steam and cooling water inlets etc.
2.1.4 Manufacturer’s leaflets giving complete descriptions of the generator, quick open valve, main breakers, relays, excitation of generator, turbine, turbine governor, etc.
2.1.5 Frontview drawing of the control panel showing meters, control lights, switches and other control devices.
2.2 Drawings and Data to Be Sent after Ordering
After having received the order, vendor shall send following drawings:
2.2.1 All drawings as per item 2, however, brought in line with purchaser’s certified requisition/specification and comments received during bidding stage.
2.2.2 Drawings showing all civil, structure and piping provisions to be made by others. These drawings have to show exact location of flanges and flange sizes of steam connections, cooling water connections, cable connections etc.
2.2.3 Control, schematic and wiring diagrams, complete with terminal and wire numbers.
2.3 Drawings and Data to Be Sent for Construction
Within two weeks after the drawings and data as per item 2.2 have been returned to vendor, vendor shall send to purchaser same drawings corrected where applicable.
2.4 Instructions
Normally 4 weeks before delivery data indicated in the order, vendor has to supply installation, maintenance and operation instructions.
2.5 Within 8 weeks after placement of the order, vendor has to send a spare part recommendation based on two years operation. Special tools required for normal maintenance shall be included in the delivery.
3. Operation
The turbine generator set serves the purpose to ensure uninterrupted (3 ph./1 ph) electricity to electrical and electronic instruments, emergency lighting, electric motors, etc. Load and power factor are indicated in the requisition.
Under normal operating conditions the generator is running in parallel with the network. Power will under these conditions be supplied by the network for about 90% and the rest will be supplied by the turbine generator set.
In case of disturbance of the network feeder, the load shall be taken over without interruption by the turbine generator set by opening of the main steam valve, the network will be automatically disconnected.
The energy necessary to overcome the time between power failure and full open position of the steam valve, will come from the rotating energy of the turbine generator set.
A flywheel shall be provided if necessary to guarantee the admissible frequency dip during power failure.
The energy, which is going into the network during power failure will be restricted by choke(s), which is connected between the network and the turbine generator set. When generator is working under normal circumstances the choke is in service.
The bypass line of the turbine shall incorporate ± 10% of the total generator capacity during normal operation. The bypass line must be adjustable between 0 - 30% of the full load of the generator.
The bypass hand control valve, shall be of the globe body, hardened trim type, and shall be provided with a locking device.
The mechanical overspeed trip device provided at the turbine shall be designed such that when full load of generator will be immediately reduced to a 10% load it shall not trip the turbine.
Turbine shall be designed such that it will operate at its maximum efficiency when generator is 10% loaded.
4. Generator
Generator shall be of the self ventilated type with curved blade ventilator, mounted within the generator. Exhaust of the air is on the turbine side.
Enclosure shall be in accordance with DIN 40050 class P22 for the generator and P43 for terminal boxes as a minimum, unless otherwise specified in the requisition. The rotor of the generator shall be of the lamelled type to get a remanent voltage as high as possible to enable hand control between zero and maximum voltage without any electronic equipment.
The excitation voltage during normal operation shall not be higher than 60 volts DC and 60 volts to earth. The rings of the DC supply to the rotor shall be provided with four brushes in such a way that changing of the brushes during normal operation of the generator can be done without loosing generator voltage or any danger. The protection cover of the brushes shall be easy removable and the brushes shall be easily accessible.
The ambient temperature of the generator will be maximum 50oC.
The bearings of the generator shall be suitable for 50.000 hours continuous operation, without overhaul, but greasing of the bearings each 5.000 hours is not acceptable. It is not acceptable to stop the unit for greasing or regreasing the bearings. Greasing shall be possible without removing cowl or coupling guard, so extension of the greasing nipples is required.
Voltage regulating equipment shall be mounted in the panelboard.
There shall be two regulators: one automatic set and one hand set.
Changing from automatic regulator to the hand one, will be done when unit is in service and shall stay in service and generator is working on hand control on normal voltage. Panelboard shall be protected in such a way that it is not dangerous to do this change.
Changing from one to the other shall be done by handswitch, which shall be mounted behind the panelboard door.
Changing regulation from automatic to handcontrol shall be possible without interruption or loosing generator voltage.
Generator shall be of the synchronous type.
The maximum voltage dip, this is short-circuiting behind the choke, will be 15%. The disturbance of the sinus wave not more than 3% with normal frequency and under no load conditions.
The acceptable voltage variation between no load and full load conditions when generator is working on automatic control will be 2 1/2% with a maximum speed variation of 10%.
10% speed variation is only for checking automatic voltage regulator equipment and not for accuracy of turbine speed regulator.
The excitation system of the generator shall be designed in such a way, ,when there is a short circuit in the excitation cables or in the rotor or brushes, there shall be no damage of the excitation equipment. (This can be done by fast fuses, resistors or a thyristor protection).
5. Construction of Control and Distribution Board
5.1 Except openings for cable entries and ventilation holes, boards shall be completely metal enclosed and compartmented.
5.2 Circuit breaker, busbar compartment, cable connection compartment, relay compartment, etc. , shall be separated from each other by insulated partitions.
5.3 Doors in which electrical equipment is mounted shall be grounded by means of flexible stranded copper connection to the stationary part of the board.
5.4 All doors shall be equipped with a lockable latch.
5.5 Boards shall be free-standing on the floor and no external bracing shall be required.
5.6 Meters, signal lights, switches shall be installed on hinged doors.
5.7 The external and internal metal parts of the enclosure and the baseplate shall be provided with 3 coats of paint, according to paint manufacturer’s instructions. These 3 coats shall form a paint system with a high resistivity against site conditions mentioned. All painting damaged during testing, transport shall be repaired with same type of paint used in the factory.
5.8 The minimum size of the meters on front of panel shall be 96 square.
5.9 All equipment mounted on doors and carrying a voltage higher than 42 volts shall be insulated to prevent accidental contact.
5.10 The lockable control switch which shall control the “bypass choke contactor” shall be mounted behind panel door.
5.11 Speed control switch shall be provided with a locking device.
5.12 A panel construction where back access is required to change equipment to repair or connect equipment is not acceptable.
6. Busbar System
6.1 Main bus shall be rated as indicated on the drawings.
6.2 The maximum permissible temperature rise of busbars shall be 30oC.
6.3 All buses shall be dynamically braced for short circuits as shown on the drawings.
6.4 Bus colors shall be as specified in the requisition.
6.5 A bare copper ground bus of one piece shall extend throughout the length of the panel. The groundbus shall be mounted directly on the panel structure/. The minimum size of the groundbus shall be 25 x 5 mm. Near the connections and/or terminals for the outgoing cables branch ground buses have to be installed with at least one earthscrew for each outgoing of incoming cable.
6.6 Busbar joints shall be made by galvanized or cadmiumplated high tensile strength steel bolts, nuts and washers and secured against loosening. Minimum distance of any part of the busbar system to ground shall be at least 25 mm.
6.7 Busbars shall be made of hard-drawn highconductivity electrolytic cooper.
6.8 The busbar supports and end barriers shall be made of high quality non hygroscopic insulating material.
The busbars shall not be mounted above the arcing chutes of the breakers.
If equipment is mounted above the breakers an insulation partition barrier shall be mounted at least 25 cm above the arcing chutes.
Without removal of the insulation plates it shall be impossible to touch the busbar system when frontdoors are open.
7. Wiring and Marking
7.1 Cable tray and cable clamps shall be provided to mount all incoming and outgoing cable within the switchboard.
7.2 Insulated wireways shall be provided for wiring between different vertical sections without going outside the equipment.
7.3 Control wires shall be 1,5 mm2 - 750 volt within the control board, provided that control fuse rating does not exceed 10 ampère. If 16 amps control fuses are installed control wiring has to be at least 2,5 mm2. CT wires shall be at least 4 mm2 - 750 volt. Wirings shall be of the stranded type. Connections shall be made by cable lugs or wire pins. Fuses less than 10 ampères are not acceptable. All fuse holders shall be of the vibrationproof type.
7.4 Provisions shall be made for terminating each incoming and outgoing cable with a separate screwed or bolted cable terminator supplied with the control board.
7.5 Terminals shall be grouped with regards to their different voltages. There shall be a minimum of 5 cm space or a divider of insulating material between terminal block carrying different voltages.
7.6 Each wire and each terminal shall be numbered in accordance with the potential numbering in the one line diagram or schematic diagram. The wiring number shall be same number as terminal number.
7.7 The distance between terminals and other equipment or between terminals and wireducts shall be at least 7 cm.
7.8 The wires shall not be joined or tied between terminal points.
7.9 Wires shall be neatly arranged, the use of wireducts with a removable cover is acceptable.
7.10 All terminal screws shall be provided with lock nuts to prevent connection failures.
7.11 All relays, fuses, switches, terminals, etc. shall have identification markers and shall be in accordance with certified drawings.
7.12 Each wire shall be terminated in a separate terminal: so two separate wires in one side of terminal are not allowed.
7.13 All control wiring, limit switches and coils on turbine and quick open valve shall have a heat resistant insulation, and wiring shall be protected with a high quality flexible tube.
8. Quick Open Valve
8.1 No rectifiers, electronic equipment or transformers shall be mounted on the quick open valve.
8.2 Maximum ambient temperature of switches mounted on the quick open and auxiliary valves will be 80oC.
8.3 Maximum temperature of coils mounted on the quick open valve will be 80oC.
8.4 Cable entries on the quick open valve shall be on the place with the lowest temperature.
8.5 Main valve shall be of the type air to close, with hand reset. Auxiliary valve shall be of the three way type.
8.6 Manufacturer of the main valve shall be Masoneilan-Annin. Manufacturer of the three way type shall be Asco.
8.7 The time from closed position of main valve to full open position shall be maximum one second.
9. Baseplates
9.1 Baseplate shall be mounted on top of concrete foundation and not poured in the foundation.
9.2 Welded steel baseplate shall be required.
9.3 Glued baseplate on the foundation is preferable.
9.4 It is not allowed to weld on the baseplate after mounting and aligning of the generator and the turbine on the baseplate.
9.5 Baseplate shall be provided with lifting eyes to permit easy transport of the set. The lifting eyes on turbine and/or generator shall be removed before shipment of the unit, (because these eyes are not suitable to lift the entire unit).
9.6 Generator and turbine shall be mounted on baseplate with bolts and cylindrical adjusting pins. These pins for turbine and generator shall be mounted on one side of the turbine generator set.
10. Tests
The manufacturer shall perform the following tests at factory:
10.1 One minute high potential test on the whole unit.
10.2 Megger test with 500 volt megger on the whole unit.
10.3 Heat run test for 24 hours uninterrupted. Unit shall operate under full load steam conditions.
10.4 Good working of regulating equipment by hand control and automatic control.
10.5 Checking of the whole unit including but not limited to:
a. Changeover from “net load” to “generator load”
b. Synchronizing of generator with grid
c. Speed control of turbine
d. Good working of quick open valve
e. Temperature measuring of all electrical equipment mounted on quick open valve
f. Overspeed of turbine
g. During overspeed, the voltage of the generator shall to stay within the specified range
h. Replacement of brushes when generator is working under full load conditions
i. Adjustment of bypass valve (see item 17).
10.6 The following oscillograms are required:
Sinus wave under no load conditions
10.7 Suddenly changing of power from no load to full load and from full load to no load conditions.
10.8 Short circuiting of choke for 2 seconds.
10.9 Short circuiting of network (grid protection by means of fuses).
10.10 10.9 shall be done two times:
a. When choke is in service
b. When choke is not in service.
10.11 Check temperature electronic equipment. Maximum temperature of electronic equipment shall be 60oC.
10.12 Vibration test.
10.13 Noise level test for whole unit. Maximum acceptable sound pressures are:
| Center Frequency of Octave Band | Sound Pressure in dB (ref. press. 2x10-5N/M2) |
| 63 | 98 |
| 125 | 95 |
| 250 | 95 |
| 500 | 87 |
| 1000 | 82 |
| 2000 | 79 |
| 4000 | 79 |
| 8000 | 82 |
Total noise level 85 dB (a)
11. Instruction Plates
11.1 Instruction plates shall be mounted on:
a. Control board
b. Near the bearings, showing regreasing period, trade, kind and quantity of grease required
c. Near the filling plug of the turbine oil system showing trade and type of oil
d. Near the filling plug of the oil tank of the chokes showing trade and type of oil
e. At the filters showing cleaning periods
f. All indicators mounted on turbine and cooler
12. List of Recommended Supplies
| Auxiliary relays and time delay relays | ASEA | Brown Boveri |
| Protection relays | ASEA | Brown Boveri |
| Metering equipment | Nieaf | |
| Breakers | Merlin and Gerin | |
| Transformers | ||
| Chokes (oil immersed) | REM | |
| Contactors | Stotz/Telemecanique | |
| Signal lights | Faget (with metal housings) | |
| Switches | Hazemeyer/Vinkyr | |
| Fuse holders | Siemens/Hazemeyer | |
| Fuses knife type screw type | Siemens/Hazemeyer Siemens | |
| Rectifiers (metal type) | Westinghouse or AEG | |
| Transistors | Siemens/ITT/Philips | |
| Tyristors | General Electric/ASEA | |
| Resistors | Rosenthal from 2 W up, under 2 W Beyschlag | |
| Capacitors | Philips | |
| Electrolytic capacitors | Philips | |
| Terminals | Phoenix | |
| Insulators (resin type) | ||
| Diodes | Philips | |
| Generator |
13. Turbine
The turbine shall be provided with the following protection devices:
a. Low pressure switch lubricating oil
b. Low pressure switch regulating oil
c. High temperature switch lubrication and regulating oil
d. Low temperature switch regulating oil
e. Low flow switch cooling water
f. Overspeed turbine
g. Low oil pressure will close the governor and stops the turbine
h. Coupling guard.
The turbine shall be provided with the following indicating devices:
a. Actual steam pressure and temperature
b. Steam pressure exhaust
c. Lubricating oil pressure
d. Regulating oil pressure
e. Temperature oil
f. Differential pressure of filters
g. Temperature cooling water on both sides of the cooler
h. Speed indicator
i. Cooling water flow indicator
14. Oil Cooler
The cooler shall be provided with the following devices:
a. Hand control valve cooling water
b. Thermometer cooling water
c. Thermometer in oil circuit
The cooling water hand control valve shall be mounted on the outgoing cooling water side of the oil cooler.
The low flow switch cooling water shall be mounted between hand control valve cooling water and outgoing side cooling water oil cooler.
15. Starting of Turbine
The turbine shall be built in such a way that one man can start the turbine, without using tools or other special equipment.
16. Starting of Motors
Starting of big motors on the turbine generator set will be done only when choke is not in service. That means:
a. Generator is running not parallel with network, and steam-valve in full open position
b. Generator is running parallel with network but choke shall be “bypassed” by a contactor or breaker.
It shall be possible to short circuit the choke by a push-button, which will be located near the rotary switch of the motor(s). The panelboard shall be provided with terminals for it. This is an addition to point 5.10.
17. Adjustment of Bypass Valve
Open the by pass and main valve fully. Adjust the speed of turbine with speed control switch, so that the generator is running with the same frequency as the network.
Turn bypass switch choke in “bypass choke” position. Synchronize the generator with network. Adjust with the speed control switch the output of generator, so that generator is fully loaded. Close by hand the main steam valve. After closing the main valve adjust the bypass valve in such a way that generator will be 10 - 15% loaded.
When generator is steady bring choke again in service.
18. Choke
Chokes shall be oil immersed and totally enclose. For outdoor use in chemical atmosphere choke shall not be located in the controlboard or distributionboard. Choke shall be connected by cables to the controlboard.
19. Power Transformer
The transformer shall be oil immersed type and totally enclosed for outdoor use in chemical atmosphere. Transformer shall not be located in the controlboard or distributionboard. Transformer shall be connected by cables to the controlboard and distributionboard. Transformers shall be equipped with level indicator, cable boxes, temperature indicator, lifting lugs, nameplate, etc. Windings shall be suitable braced to withstand a short circuit in the transformer terminals, and insulated for a ungrounded exposed installation. Transformer shall be of the double winding type.
20. Rotor and Vibrations
Rotor and fan shall be dynamically balanced with half coupling mounted on the shaft. For vibration see German VDI 2056, dated October 1964.
Maximum acceptable vibration velocities:
| Group | Stufe |
| K | 0,71 |
| M | 1,12 |
| G | 1,8 |
| T | 2,8 |
Rotor and fan shall also be statically balanced to ensure a smooth running out of the motor. Half coupling may not be used for balancing of the rotor. Rotors shall be given a corrosion resistant coating after balancing.