Q & A in the Fundamentals of Electrical Power Systems

This unique approach to teaching and the important questions have been designed to cater to all engineering and technical levels, starting from university students in engineering and various technical institutes to specialized engineers with extensive experience in power and distribution systems.

The course presents practical questions and answers, focusing on simple theoretical concepts while placing greater emphasis on images and explanations from real-life applications. This way, we can link theoretical academic study with what exists in practical applications after completing this course.

Our course is closely related to electrical power systems and electrical distribution systems, and in this course, we present ideal answers to the following questions:

(1) What is the difference between alternating current (AC) and direct current (DC)?

(2) What are the components of the electrical power system?

(3) What is the main source of voltage (V), current (I), and frequency (F) in the electrical power system?

(4) What is the meaning of resistance (R)? Give examples and explain the type of current passing through it.

(5) What is the meaning of inductive reactance (X_L)? Give examples and explain the type of current passing through it.

(6) What is the meaning of capacitive reactance (X_C)? Give examples and explain the type of current passing through it.

(7) What are the types of electrical loads?

(8) What is the importance of power stations in the electrical power network and system?

(9) What are the types of power stations in the electrical power network and system?

(10) What are the different voltage levels present in the electrical power network and system?

(11) How is the frequency (50Hz / 60Hz) obtained in the electrical power network and system?

(12) What is the practical meaning of the phase angle (ϕ)? Does it differ in a 50Hz system compared to a 60Hz system?

(13) What is the difference between frequency and power frequency?

(14) What is the unit of measurement for each of the following:

electric voltage (V), electric current (I), electric power (P), electric energy (E), frequency (F), resistance (R), inductive reactance (X_L), capacitive reactance (X_C), capacitance (C), and inductance of the coil (L)?

(15) What is the relationship between electric current (I), electric voltage (V), conductor and insulator?

(16) What is the difference between electric current and leakage current?

(17) What is the relationship between electric current (I) and both voltage (V) and voltage drop (V.D)?

(18) Which is more dangerous for humans, AC or DC?

(19) What is the difference between the electric field and the magnetic field?

(20) What causes current to lag in a coil, lead in a capacitor, and be in-phase in a resistor?

(21) What are the types of electrical power and the measurement unit for each type?

(22) What is the difference between electrical power and electrical energy?

(23) What are the units of measurement for: active power, reactive power, apparent power, active energy, reactive energy, and apparent energy?

(24) What is meant by the power triangle and power factor (P.F)?

(25) What is the power factor (P.F) for capacitors, resistors, and coils?

(26) What is meant by the skin effect? What causes it, and what are its dangers? What are the best ways to mitigate it?

(27) What is the relationship between resistance in AC and DC?

(28) Calculate the rated current (A) and rated power (kVA) of the load.

(29) Calculate the rated current (A) and rated power (kW & kVA) of the motor.

(30) Calculate the reactive power of the capacitor (kVAR) needed to correct the power factor from 0.8 lag to 0.9 lag.

(31) What is the relationship between electrical resistance (R) and temperature (C°)?

(32) What is the importance of using transformers in electrical power systems and networks?

(33) What are the types of electrical transformers?

(34) Why is motor power measured in HP, but transformers are not?

(35) What are the main components of a power/distribution transformer?

(36) Why do transformers operate on AC and not on DC?

(37) What is the importance of oil in electrical transformers?

(38) What do the terms (ONAN) and (ONAF) mean, and what is the difference between them?

(39) What is the importance of the tap changer in transformers? What are its types, and where is it installed in the transformer?

(40) What does the symbol (Z%) mean in electrical transformers?

(41) What does the term Dyn11 refer to?

(42) What are the main conditions for connecting transformers in parallel?

(43) What is the difference between line voltage (V_line) and phase voltage (V_phase), as well as line current (I_line) and phase current (I_phase)?

(44) What is the difference between nominal voltage and rated voltage?

(45) What are the main components of power cables?

(46) What are the main metallic materials used in power cables? Mention their advantages and disadvantages and which is better.

(47) What are the main insulating materials used in power cables? Mention their advantages and disadvantages and which is better.

(48) What is the difference between transmitting electrical energy using underground cables and overhead lines (OHTL)?

(49) What are the types of power cables?

(50) What is the difference between the neutral point (N) and the earth point (E)?

(51) What are the types of earthing and the importance of each type?

(52) What is the difference between touch voltage and step voltage?

(53) What are the essential components of any earthing system?

(54) What is the value of the earth resistance (E) in H.V substations and distribution networks?

(55) What are the measuring transformers in the electrical network?

(56) What is the importance of installing current transformers (CTs) in the electrical network?

(57) What is the importance of installing voltage transformers (VTs) in the electrical network?

(58) How are current transformers (CTs) and voltage transformers (VTs) connected to the electrical network?

(59) What are the main installation points for current transformers (CTs) in the electrical network?

(60) What are the main installation points for voltage transformers (VTs) in the electrical network?

(61) What is the problem of opening the secondary circuit of a current transformer (CT)?

(62) What are the main measuring devices connected with current transformers (CTs)?

(63) What are the main protection devices connected with current transformers (CTs)?

(64) What are the main measuring devices connected with voltage transformers (VTs)?

(65) What are the main protection devices connected with voltage transformers (VTs)?

(66) What are the main measuring devices connected with both current transformers (CTs) and voltage transformers (VTs)?

(67) What are the main protection devices connected with both current transformers (CTs) and voltage transformers (VTs)?

(68) What is the fundamental difference in the working principle of power transformers, voltage transformers (VTs), and current transformers (CTs)?

(69) What are the types of faults that may occur in the electrical network?

(70) What is the difference between symmetrical and unsymmetrical faults?

(71) What is the difference between earth faults & phase faults?

(72) What are the essential elements and components of any protection system?

(73) What are the main measuring devices present on power transformers?

(74) What are the main protection devices present on power transformers?

(75) What is the principle of operation of the differential protection device on transformers?

(76) What are the main protection devices found on transmission lines?

(77) What is meant by Symmetrical Components?

(78) What is the importance of short-circuit current calculations (S.C calculations) and the related factors?

(79) What is the most dangerous and severe type of fault (S.C)?

(80) What is a circuit breaker (C.B), and why is it used in the electrical network?

(81) What is meant by an isolating switch (disconnecting switch)?

(82) What is the difference between an Isolating Switch and a Circuit Breaker (C.B)?

(83) What are the main types of circuit breakers (C.B) present in the electrical network?

(84) What is the difference between overload and overcurrent?

(85) Where are circuit breakers (C.B) mainly installed in the electrical network?

(86) Why are high and extra-high voltages used to transmit electrical energy through overhead transmission lines (OHTL)?

(87) What are the main components of overhead transmission lines (OHTL)?

(88) What are the main accessories for overhead transmission lines (OHTL)?

(89) What types of towers are used in overhead transmission lines (OHTL)?

(90) What is the importance of using transposition towers in overhead transmission lines (OHTL)?

(91) What is the primary function of insulators used in overhead transmission lines (OHTL), and what are their types?

(92) Name two types of conductors used in overhead transmission lines (OHTL).

(93) What is the Ferranti effect? What causes it, what are its dangers, and what are the best ways to mitigate it?

(94) What is the difference between high voltage direct current (HV-DC) and high voltage alternating current (HV-AC)?

(95) What is the corona phenomenon? What causes it, what are its dangers, and what are the best ways to mitigate it?

(96) What is the difference between linear loads and non-linear loads?

(97) What are harmonics? What are their types, and what are their sources?

(98) What is the importance of substations in the electrical network?

(99) What are the types of substations in the electrical network?

(100) What is the difference between AIS substations and GIS substations?

(101) What is the difference between transmission substations & distribution substations?

(102) What are the main electrical equipment in various substations?

(103) What is meant by the term (BIL)?

(104) What are the main types of insulation materials used in various equipment in the electrical power system?

(105) What is the importance of electrical interconnection between different countries?

(106) What is the importance of using surge arresters in electrical power networks?

(107) What is meant by the term SCADA system?

(108) What is meant by the term SAS?

(109) What is the importance of using a DC System in substations?

(110) Why is the 50/60Hz frequency specifically used, and why aren’t higher frequencies used in the power system?

(111) Why is there always concern about changing the grid frequency from the 50/60Hz values?

(112) What is the importance of using Earthing Transformers in substations?

(113) What are Reactive Power Compensators? And what is meant by the term FACTS?

(114) What is meant by the term ATS?

(115) What is meant by the term IP68?

(116) What are the main advantages and disadvantages of using SF6 gas in the power system?

(117) What is the difference between an Insulator and a Dielectric?

(118) What is the difference between a Synchronous Motor and an Induction Motor? And why does the former act as a source of reactive power (leading P.F.), while the latter consumes reactive power (lagging P.F.)?

(119) What is the main difference between a Circuit Breaker (C.B.) and an Overload Relay (OL) used in motor protection?

(120) Both a Capacitor and a Battery store electrical energy. What is the difference between them?