TRANSMISSION AND DISTRIBUTION SYSTEM PARAMETERS IN BANGLADESH

Restricted Working Period In Bangladeshi Electrical Project

Due to monsoon rain between July and September, work may slowdown. Due to traffic, work along /across road has to carefully plan. 

The Contractor shall obtain reliable Information concerning the conditions appertaining to the working areas covered by this Contract and shall plan his work in accordance with local conditions.

SYSTEM ELECTRICAL PARAMETERS IN BANGLADESH

230 kV Transmission System in Bangladesh

Normal Service Voltage              :   230     kV

Rated Voltage                            :   245     kV

Insulation Level -

Lightning Impulse Withstand       :  1050  kV

50Hz dry 1 minute Withstand      :  460     kV

Number of Phase                       :  3

Frequency                                 :  50       Hz

Switchgear Symmetrical Breaking Capacity     :  40  kA, 3 sec

System Earthing

The 230/132 kV auto transformers are solidly earthed

132 kV Transmission System in Bangladesh

Normal Service Voltage                               :           132     kV

Rated Voltage                                            :           145     kV

Impulse Voltage Withstand Level                 :           650     kV

Number of Phase                                        :           3

Frequency                                                  :           50       Hz

Switchgear Symmetrical Breaking Capacity   :   31.5   kA, 3 sec

Voltage Stability Limits            :           ± 10%            Volts

Frequency Stability Limits        :           48-51 Hz

33 kV Transmission System in Bangladesh

Normal Service Voltage                      :           33       kV

Rated Voltage                                    :           36       kV

Impulse Voltage Withstand Level         :           170     kV

Number of Phase                                :           3

Frequency                                          :           50       Hz

Switchgear Symmetrical Breaking Capacity   :   25       kA, 3 sec

The 33 kV system is solidly earthed at some of the 132/33 kV Grid substations and resistance earthed at some of the Grid substations.

At the Proposed 132/33 kV sub-station the 33 kV systems will be resistance earthed.

11 KV Distribution Systems in Bangladesh

Normal Service Voltage                              :           11 KV

Rated Voltage                                            :           12 KV

Impulse Voltage Withstand Level                 :           75 KV

Number of Phase                                        :          3

Frequency                                                  :           50       Hz

Switchgear Symmetrical Breaking Capacity   :   25       kA, 3 sec

System earthing                                         :           Solid Normal

Low Voltage AC System in Bangladesh

Normal Service Voltage                        :           400/230 volts

Rated Voltage                                     :           415/240 volts

Number of Phase                                 :           3 phase 4 wire

Frequency                                           :           50Hz

Switchgear Symmetrical Breaking Capacity   :   22kA, 3 sec

System earthing                                  :           Solid

D.C System in Bangladesh

For D.C. motor driven auxiliaries, tripping, indicating lamps and controls.

Normal battery voltage                :           110V nominal for new sub-stations.

Tolerance on rated voltage         :           + 10%, -15%

Voltage at various existing sites :           30V, 48V, 110V, 220V, 250V.

For Supervisory and Telecommunications

Nominal System Voltage              :          48V

Normal float charge voltage       :           53V

Tolerance on rated voltage         :           +1V, -7V