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9 ELECTRIFICATION
9.1 General
9.1.1 All electrical equipment and materials shall be of high quality and reliable. In order to avoid corrosion of H2S, materials used for producing these equipments should be corrosive resistant. Aluminum is preferable than copper for usage, if copper is requisite in these equipment as material, then corrosive resistant coating materials are applied on the surface which would contact with H2S, the material or metal elements for coating can be zinc or other suitable materials.
9.1.2 All electrical equipment shall, if not otherwise specified, comply with the applicable following codes, standards and recommendations:
IEC International Electrotechnic Commission
GB China National Standard
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9.2 Scope of Supply
The 2x6MW Geothermal Project will comprise two identical 6MW; 20kV substation and common auxiliaries.
These electrical equipment will be supplied:
Generator
Diesel generator
Step up transformer
Unit auxiliary transformer
20kV switchgear
6.3kV switchgear
0.4kVMCC
Control and relaying
Uninterruptible power supply system (UPS)
Plant DC system
Communication system
Power cable and control cable
Cable tray
Lighting system
Lightning protection and grounding
Spare
etc.
9.3 Power system
9.3.1 One 20kV busbar will be built in the mill extension. One outgoing line connected to the PLN gird on overhead. Two incoming lines connect two step-up transformers. The transformers are 20/6.3kV 10MVA.
9.3.2 Two auxiliary transformers will be build for the power plant service motors and public power. Two auxiliary transformers will be standby each other.
9.3.3 An emergency power supply system consisting of 60kW diesel generator will provides power to necessary loads for safe and accident operation.
9.3.4 Grounding system
High voltage 20kV Neutral isolated
Medium voltage 6.3 kV Neutral isolated
Low voltage 400/230V Neuter grounding solid
Detail see electrical single line drawing
9.4 Design documentation and diagram of the electrical engineering
Drawings and documents in the Supplier scope are as follows:
Document schedules.
Main electrical single line diagrams.
Single line diagrams for switchgears.
Cable tray layouts.
Cable layouts and elevations for power, control and signal cables.
Cable schedules and connection lists.
Electrical room equipment, transformer arrangement and hole openings.
Motor control center (MCC) schematic diagrams.
Switchgear interconnection diagrams.
MCC interconnection diagrams.
Interlocking logic diagrams.
Motor lists.
Electrical bill of materials.
Operation, maintenance and installation instruction manuals.
The setting values and calculation for protection relays.
Calculation for short circuit and voltage drop.
Test report for all electrical equipment. Detailed specification for each and individual equipment.
Grounding system engineering.
Lightning protection design.
Lighting design engineering.
Battery and battery capacity design.
Fire alarm system design
Lighting layout design.
Emergency lighting layout design.
All drawings, data, calculations and manuals will be written in English.
9.5 Power consumption of plant motors
The estimated installed power of the project will be 2MW, the estimated demand power will be 1.6MW. The estimate emergency power will be 50kW.
9.6 Protection relay and automatism equipment
The protection relays and automatism set shall be the microcomputer type.
The following Protection relay and automatism equipment will be installed:
9.6.1 Generator
Differential
Earthing fault (one site grounding for stator)
Over voltage
Over temperature
Over current
Excitation fault
Under voltage
Over load
Automatic manual synchronizing system
Automatic adjust excitation
Others
9.6.2 20kV outgoing line
Current and voltage fast protection 3ph
time-delay current protection 3ph
Over current protection 3ph
Earthing fault
Auto reclosing relay
Automatic and manual synchronizing system
9.6.3 20/6.3kV step up transformer
Differential
Over current
Over load
Earthing fault
Buchholz protection
Over temperature
9.6.4 6.3/0.4/0.23kV transformer
current fast protection 3ph
Over current protection 3ph
Earthing fault
Over temperature
9.6.5 Plant 0.38kV service motor
The main service plant motors will install microcomputer motor protection device.
current fast protection 3ph
Over current protection 3ph
Over load protection
Long starting time protection
Earthing fault
Low voltage
Others
9.8 DC System
DC system will comprise of the following:
Stationary batteries (220V DC)
Battery charger connected to the LT switchboard
230V DC distribution switchboard
Other accessories
The battery shall be Nickled-Cadmium type. The battery capacity will be about 150AH. The battery charger shall be monitor mode and automatic charging mode.
9.9 Lighting
9.9.1 Lighting voltage shall be 220V, single phase, 50Hz
9.9.2 Illumination levels
300 lux in control rooms and offices
200 lux in switchgear room and MCC room
200 lux in generator room and loading areas
50 lux on stairs and platforms
25 lux in the yard
9.9.3 Luminaire
Fluorescent lamp for control room, offices and some indoor working areas.
Incandescent lamp for some emergency lighting, small room, etc.
Color-improved mercury or similar types with low energy lights for high building or structure, large working areas, flood lights. etc.
9.9.4 Emergency lighting
The emergency lighting unit incorporated with battery-rectifier, normally will be used in process departments and other buildings.
The emergency lighting for control room and other important places within the power plant shall consists of incandescent lamps fed from the 220V DC battery unit.
9.10 Grounding
The 20kV and 6.3kV system normally will be neutral isolated.
The low voltage power distribution system normally will be neutral solid grounded (TN system).
The overall resistance shall not exceed 1 ohm for any path to grounding.
Conductors may be bare aluminum wire or galvanized steel.
9.10.1 Communication and Uninterruptible power supply system (UPS)
Any required equipment and communication service will be provided.
One set of uninterruptible power supply system (UPS) (3kVA ) will be provided
9.10.2 Technical specification for electrical equipment
All enclosure and equipment shall be tropicalized.
Detaisl see technical Schedules
A. 20kV switchgears and 6kV switchgears
Switchgear shall be complete with protection and other necessary metering, testing, operating devices and special tools.
The space heater shall be installed.
B. 20kV Circuit breaker and 6kV circuit breaker
he circuit breaker consist of spring charging of manual and motor driven. The control voltage of the circuit breaker is 220DC.
C. 380V Switchboard
The circuit breakers in the switchboard shall be of draw out or fixation type. The Cubicles shall be arranged in free standing vertical assemblies with ten small size starters at most in a single stack. The bottom enclosure of each stack should not contain a starter, it may be used for connections and fittings. The center itself be sized for future expansion. The starter and all controls for each motor shall be in single enclosure.
An automatic space heater shall be installed.
D. Transformers
The step up transformers will be oil immersed type.
The unit auxiliary transformers will be try type.
Detail see technical Schedules.
E. Motor
Low voltage AC Motor
Most of the motors will be squirrel cage induction type, and normally started directly on line.Soft-starter will be supplied as necessary. Motors from 0.37 to 200kW shall be 380V.
Type
Rated voltage 380V
Frequency 50Hz
Insulation class F
Protection class IP54
Cables and Wiring
All conductors that are exposed to air shall be aluminum or zinc coated copper.
Armored cable shall be used except where specific applications require conduits.
Low voltage power cable
Type Series YJLV
Rated voltage 1kV
Insulation XLPE
2. High voltage power cable
Type Series YJLV
Rated voltage 6kV
Insulation XLPE
3.Control cable
Type Series KVV
Rated voltage 0.5kV
Insulation PVC
G. Spare parts
The Vender shall supply spare parts for two years operation.
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