55. التبريد نظام
ONAN
- Natural Oil circulation
- Natural Air circulation
Radiators
Natural Oil circulation
Forced Air circulation
Radiators + fans
ONAF
OFAF
Forced Oil circulation
Forced Air circulation
Pump + air cooler (fans +
tubes)
The air cooler can be fixed on the HV or
MV side
72. on load
نوع الجهد مغير
Diverter Switch
Connection leads
Tap Selector
Connection terminals
for tap winding
73. نوع الفولتيه مغير
Your On-Load
Tap Changer
Your transformers :
- nominal voltage = 33 000 V ( o.o15 × 33000= 495)
- upper voltage : 33 000 Volt + (5 x 1.5 V) 35 475 V
- lower voltage : 33 000 Volt - (7 x 1.5 V) 29 535 V
74. الطور زاوية
نوع المحولة
Y/ Δ
Clock-hour
figure
Ex : D yn 11
The clock - hour figure defines
the phase displacement between
HV and LV windings.
The vector rotation is anti - hour
83. Bus-bars
التوزيع قضبان
The outdoor bus-bar are either of rigid or of the strain
type.
In the case rigid type bus arrangement aluminium
pipes are commonly used. Sizes of pipes commonly
used for various voltages are given:-
33kv 40mm
66kv 65mm 400kv 100mm
132kv 80mm
84. In strain type bus-bar are overhead system of
wires strung between two supporting
The stringing tension may limited to 500---900kg
depending upon size of conductor used. This
arrangement is more economical than rigid.
The strain type are ACSR and all aluminum
conductors.
66kv 37
/
2.79mm ACSR
132kv 37
/
4.27mm ACSR
400kv 61
/
4.27mm ACSR in duplex
Bus-bars
التوزيع قضبان
85. Common arrangements of bus-bars
التوزيع لقضبان الشائع التنظيم
1- Single Bus-bar.
2- Single Bus-bar with Bus Sectionalize.
3- Double Bus-bar.
86. Single Bus-bar
المفرد التوزيع قضبان
The arrangement is simplest and cheapest and
it suffers from two major defects
1- Maintenance without interruption of
supply is not possible
2- Extension of sub-station of
supply is not possible
88. Single Bus-bar with Bus Sectionalizer
المجزئ المفرد التوزيع قضبان
Advantage of the scheme is realized if the
incoming and outgoing circuits are distributed
Evenly on the sections
90. Double Bus-bar system
القضبان نظام
المزدوج
1- main and transfer bus-bar
2- Double bus-bar Single Breaker
3- Double bus-bar Breaker and half
4- Double bus-bar Double Breaker
91. Double Bus-bar
1- each load may be fed from either bus
2- the infeed and load circuits may be divided
into two separate groups if needed from
operational considerations
3- either busbar may be taken out for
maintenance and cleaning of insulators
95. Breaker and A Half
والنصف القاطع نظام
This is improvement over the double breaker scheme
to effect saving in the number of circuit-breakers.
For every two circuits only one
spare breaker is provided
in this case.