Punjab PSEB Matric NSQF Power case studies
Punjab PSEB Matric NSQF Power · Put your knowledge to work in context.
The Punjab School Education Board (PSEB) was set up by a legislative enactment in November 1969, and its Class 10 (Matriculation) examination is the board's main school-leaving assessment for Punjab. Within that examination, the NSQF vocational stream lets candidates offer a trade subject - here, Power - alongside their general subjects. The Punjab PSEB Matric NSQF Power case studies are 5 cases and about 3,781 words.
1110% Loading and 12% Unbalance on a Village Distribution Transformer
A 100 kVA, 11 kV/433 V ONAN distribution transformer (nameplate full-load current 139 A) supplies 180 domestic connections and 12 agricultural pump-sets through a 400 m LT line. During a June evening survey the lineman records: top-oil temperature 78 °C, ambient 38 °C, LT line currents L1 168 A, L2 172 A, L3 121 A, and a tail-end voltage of 372 V.
791 words, about 4 min2Pump Motor Tripping: Should the Overload Relay Be Raised?
A 7.5 kW (10 HP), 415 V, three-phase, 4-pole squirrel-cage motor drives a submersible pump through a star-delta starter. Nameplate full-load current is 14.2 A and the thermal overload relay is set at 14 A.
727 words, about 4 min3CT-Operated Meter Billing Half the Real Consumption
An LT three-phase four-wire CT-operated energy meter serves a 55 kW flour mill. The CTs on site are nameplated 200/5 A, class 1.
749 words, about 4 min411.5 Ω Earth Resistance and Three Quick Fixes
A 100 kVA transformer in a sandy-soil area has its neutral, the LT panel body and a nearby streetlight pole all bonded to a single 40 mm diameter, 3 m long GI pipe electrode. In May, a three-pole fall-of-potential test taken with the transformer disconnected gives 11.5 Ω.
752 words, about 4 min5Rooftop Inverter Tripping on Over-Voltage at Midday
A 10 kWp three-phase grid-tied rooftop solar plant on a school has its inverter mounted beside the AC distribution board, 60 m of 4 mm² single-core copper cable away from the net-metering point. Since April the inverter has shut down around 13:00 each day with an over-voltage fault and restarted 10–15 minutes later, losing an estimated 3 kWh per day.
762 words, about 4 min