UPDA-6 - Notes | FM Electricals

🏭 1. WHAT IS A POWER SYSTEM?

Power System is an interconnected network of components that generates, transmits, and distributes electrical energy from power plants to consumers.

Power System = Generation + Transmission + Distribution + Load

📌 Main Components:
• Generating Station: Produces electrical power
• Transmission Line: Carries power over long distances
• Substation: Steps voltage up/down
• Distribution Line: Delivers power to consumers
• Load: Consumes electrical power

⚡ 2. GENERATION (विद्युत उत्पादन)

Electrical energy is generated by converting mechanical energy into electrical energy using generators.

Type	Source	Efficiency	Capacity
Thermal Power Plant	Coal / Gas / Oil	35-40%	500 MW - 5000 MW
Hydro Power Plant	Water	85-90%	100 MW - 10,000 MW
Nuclear Power Plant	Uranium	30-35%	500 MW - 1500 MW
Solar Power Plant	Sunlight	15-20%	1 MW - 500 MW
Wind Power Plant	Wind	35-40%	1 MW - 200 MW

📊 3. GENERATION VOLTAGE LEVELS

Type	Typical Voltage
Thermal Power Plant	11 kV, 13.8 kV, 22 kV
Hydro Power Plant	6.6 kV, 11 kV, 13.8 kV
Nuclear Power Plant	22 kV, 33 kV
Solar / Wind	0.4 kV, 11 kV

⚠️ Important: Generated voltage is stepped up for transmission to reduce losses.

🔋 4. TRANSMISSION (विद्युत संचरण)

Transmission is the bulk transfer of electrical power from generating stations to substations located near load centers.

Voltage Level	Category	Distance
132 kV, 220 kV	Primary Transmission	100-300 km
400 kV, 765 kV	EHV Transmission	300-800 km
800 kV, 1200 kV	UHV Transmission	800+ km

Transmission Efficiency = (Power Delivered / Power Sent) × 100%
Typical Efficiency: 90-95%

🏗️ 5. TRANSMISSION LINE TYPES

Type	Construction	Advantages	Disadvantages
Overhead Line	ACSR conductors on towers	Cheaper, easier to repair	Weather affected, visual impact
Underground Cable	XLPE/Oil filled cables	No visual impact, safe	Expensive, difficult repair

📐 6. TRANSMISSION LINE PARAMETERS

Resistance (R): Causes I²R loss, depends on conductor material
Inductance (L): Due to magnetic field, causes voltage drop
Capacitance (C): Due to electric field, causes charging current
Conductance (G): Due to leakage current (very small)

Surge Impedance: Zc = √(L/C)
Surge Impedance Loading (SIL): SIL = V² / Zc

🏘️ 7. DISTRIBUTION (विद्युत वितरण)

Distribution is the final stage of power delivery from substations to end consumers.

Type	Voltage	Consumer Type
Primary Distribution	11 kV, 33 kV	Industrial, Commercial
Secondary Distribution	415 V, 230 V	Residential, Small Commercial

📌 Distribution System Configurations:
• Radial System: Simple, cheapest, least reliable
• Ring Main System: More reliable, used in cities
• Interconnected System: Most reliable, highest cost

🔧 8. AC vs DC TRANSMISSION

ParameterAC TransmissionDC Transmission Voltage TransformationEasy (using transformers)Difficult (needs converters) Line LossesHigher (skin effect + reactance)Lower (no skin effect) Number of Conductors3 (3-phase)2 (positive + negative) DistanceUp to 800 km> 800 km (economical) CostLower for short distancesLower for long distances

📊 9. INDIAN & QATAR POWER SYSTEM

ParameterIndiaQatar Frequency50 Hz50 Hz Generation Voltage11 kV, 33 kV11 kV, 33 kV Transmission Voltage132 kV, 220 kV, 400 kV, 765 kV66 kV, 132 kV, 220 kV Distribution Voltage11 kV, 415 V, 230 V11 kV, 415 V, 230 V National GridNATIONAL GRID (One Nation One Grid)KAHRAMAA Grid

📝 10. IMPORTANT FORMULAS

Power (3-phase) = √3 × V_L × I_L × cos φ
Transmission Efficiency = (P_rec / P_send) × 100%
Voltage Regulation = (V_nl - V_fl) / V_nl × 100%
SIL = V² / Zc

🗺️ 11. SINGLE LINE DIAGRAM (SLD)

Single Line Diagram (SLD) is a simplified representation of a power system showing all major components using standard symbols.

📌 Components shown in SLD:
• Generators • Transformers • Circuit Breakers • Isolators
• Bus Bars • Transmission Lines • Loads • Protection Relays

🏭 12. SUBSTATION

Substation is an assembly of equipment that transforms voltage levels and switches circuits.

Type	Purpose	Voltage Level
Step-up Substation	Increases voltage for transmission	11/132 kV, 11/220 kV
Step-down Substation	Decreases voltage for distribution	132/33 kV, 220/66 kV
Distribution Substation	33/11 kV, 11/0.415 kV	Supplies consumers

🔌 13. SUBSTATION EQUIPMENT

Equipment	Function
Transformer	Steps voltage up/down
Circuit Breaker (CB)	Interrupts fault current
Isolator (DS)	Provides visible isolation
Lightning Arrester	Protects against surges
CT & PT	Measures current & voltage
Bus Bar	Common connection point

🔌 14. POWER CABLES

TypeVoltageInsulationApplication LT CableUpto 1 kVPVC/XLPEDistribution HT Cable1 kV to 33 kVXLPEPrimary Distribution EHV Cable66 kV to 400 kVXLPE/Oil FilledTransmission

⚡ 15. INSULATORS

Insulators provide electrical isolation between live conductors and supporting structures.

Type	Voltage Range	Application
Pin Insulator	Upto 33 kV	Distribution lines
Disc Insulator	11 kV to 765 kV	Transmission lines
Strain Insulator	High voltage	Dead ends, corners
Post Insulator	Upto 400 kV	Substations

🏗️ 16. TRANSMISSION TOWERS

Tower Type	Angle	Use
A-Type Tower	0° - 2°	Straight lines
B-Type Tower	2° - 15°	Small deviation
C-Type Tower	15° - 30°	Medium deviation
D-Type Tower	30° - 60°	Large deviation
Dead End Tower	60° - 90°	Termination

📊 17. LOAD CURVE

Load Curve shows variation of load with time.

Daily Load Curve: 24-hour variation
Monthly Load Curve: Load variation over a month
Annual Load Curve: Yearly variation

Load Factor = (Average Load) / (Maximum Load)
Diversity Factor = (Sum of Individual Max Demands) / (Maximum Demand of System)
Plant Capacity Factor = (Actual Energy Generated) / (Max Possible Energy)

⚡ 18. LOAD TYPES

Load Type	Characteristics	Examples
Domestic Load	High in morning/evening	Lights, fans, TV, refrigerator
Commercial Load	High during business hours	AC, lighting, computers
Industrial Load	Continuous, high power	Motors, heaters, furnaces
Agricultural Load	Seasonal, high during day	Pumps, irrigation

💰 19. POWER FACTOR & TARIFF

Power Factor = cos φ = P / S
Low PF Penalty = (Target PF - Actual PF) × Rate

Tariff TypeDescription Simple Tariff Rate per kWh consumed Two-Part Tariff Fixed charge + Energy charge Three-Part Tariff Fixed + Energy + Demand charge Time of Day Tariff Peak hours = higher rate

⚠️ 20. TYPES OF FAULTS

Fault TypeDescriptionOccurrence Symmetric Fault 3-phase short circuit 5% of faults Line to Ground (LG) Single line to ground 70-80% of faults Line to Line (LL) Two lines shorted 15% of faults Double Line to Ground (LLG) Two lines to ground 10% of faults

🛡️ 21. PROTECTION SCHEMES

Overcurrent Protection: For overload and short circuit
Differential Protection: For transformers, generators
Distance Protection: For transmission lines
Buchholz Relay: For transformer internal faults
Lightning Arrester: For surge protection

📊 22. IMPORTANT FORMULAS

Fault Current = Voltage / Impedance
Symmetrical Components: I_a = I₀ + I₁ + I₂
Short Circuit Capacity = √3 × V × I_sc (MVA)
Breaking Capacity = √3 × V × I_breaking (MVA)
Making Capacity = 2.55 × Breaking Capacity

📚 POWER SYSTEM • COMPLETE NOTES