Electrical Hook up general note for instrument installation

1. Instrument hook up and installation for instrument wiring system shall be accordance with specifications (Instrument design basis & instrument installation specification)
2. The hook up and installation drawings shown in general the required position of the instrument relative to measuring point. The exact location shall be determined at the site with the aid of instrument location drawings
3. All instruments shall be installed in such a way that they are not subjected to
   - Unable to access
   - excessive vibration
   - extreme environment conditions
   - obstruct traffic
   - periodic maintenance of adjacent equipmentbe installed in place which are prone to leakage/dripping
4. Sufficient space shall be left around the instrument for instrument cover removal /withdrawal and for removal protective shades. The minimum clearance between any parts and instrument and surrounding structures or equipment shall not be less than 0.2m to allow insulation, painting, etc
5. Sufficient flexibility shall be provided in instrument cable line to allow thermal expansion the line equipment to which they connect
6. All fabricated work in the field shall be grounded smooth and painted as per project standards. All painting shall be carried out before attachment of instruments, cables, tubing, etc. to the painted materials
7. All instrument cables and wiring shall be identified with the drawings and as detailed in instrument basis. Instrument cable shall be tagged with 316SS tags at walls, penetration and at the end points
8. Wiring to terminal blocks shall not exceed two connections per terminal point
9. A short coil of cable shall be made in field cable at instrument
10. Every wire in every cable including spare wires and drain wires shall be terminated with a company approved insulated ferule, on rail mounted terminal blocks , at both end
11. Each terminal point (including end devices, junction boxes and marshalling strips) shall be made up to include heat shrink insulation over cable and wire shields, end and bare drain wires
12. All cable shields shall be earthed at IER (Instrument Equipment Room) and CCR (Control Center Room) only. Individual shields drain wires for pairs and triad shall be cut, coil and taped at the instrument head
13. All multi core pair and triad overall shields and drain wires shall be insulated green/yellow colored PVC sleeving
14. All metallic components, others than current carrying conductors shall be connected to a common earth system. All unused cable cores shall be earthed at one end only
15. cable runs that penetrate walls (E.G. building walls, blast walls and fire walls) that separate safe area hazardous (classified) shall be provided with vapor tight cable transits fire rated to meet the fire wall requirements
    

Generator Electrical Protective Relay Devices base on ANSI

Over excitation protection Volt/Hertz relay (ANSI No.24)

Relay ini harus di-set untuk meng-counter high induction
proporsional dengan V/f, yang mengakibatkan thermal
overloading. These may occur during starting and shut

Picture :

ABB-product series-compact and integrated with multi protectiondown under full load condition




Under voltage relay (ANSI No.27)
This relay prevents generator/motor to operate below normal voltage/frequency operating system cause by AVR or internal faults. Time delay must be set slower than transient system voltage dip and must be faster than too much slowing down generator and make re accelerate to meet proper plant recovery

Reverse power relay (ANSI No. 32)
This device protects generator to receive power from system in case of failing prime mover to drive generator. Turn back power may damage generator.

Lost of excitation relay (ANSI No. 40)
Faulty in generator field excitation circuitry causes generator loss of excitation. In this case generator will act as induction generator which received reactive power from system. This condition will make instability in power system and over heating on damper rotor windings

Negative sequence relay (ANSI No.46)
These are included to detect phase unbalance, phase reversal, and phase sequence fault. These abnormal condition will heat machine windings. This kind of relay is more independent to do close/open power system

Inadvertent energizing relay (ANSI No. 50/27)
Due to unintentionally energizing will make generator damage. This relay will limit down possibility of generator damage. Actually this relay is combination of over current relay and under voltage relay with controlling electronic digital logic.

Breaker failure relay (ANSI No.50BF)
In the event of a downtimes or faulty in generator, generator can remain online if the breaker is defective or substantial damage. This protection will measure minimum breaker current and thru auxiliary contact. It can be activated via internal protective tripping or externally via binary input

Sensitive earth fault relay (ANSI No.50/51G)
This device is for Limiting damage of generator in the event of rotor earth fault. The sensitive earth fault can be use as separate earth fault protection

Definite time over current relay (ANSI No.50/51)
This is short circuit protective device

Inverse time over current relay (ANSI No 51V)
This is also short circuit protective device with ANSI and IEC curve characteristic respond. This can be selected base on system requirement

Over voltage relay (ANSI No.81U)
This protect generator voltage regulator that could be damaged in an over voltage condition due to AVR failure or manual voltage control errors. A time delay is provided to prevent tripping under transient voltage spikes