Electrical Distribution System Question & Answers June 27, 2023 By Wat Electrical This article lists 75 Electrical Distribution System MCQs for engineering students. All the Electrical Distribution System Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of Electrical Distribution System. An Electrical Distribution System is a network of electrical components and devices used to deliver electrical power from the generation source to various end users or loads. It plays a crucial role in the transmission and distribution of electricity across residential, commercial, and industrial areas. The electrical distribution system typically starts at a power generation plant, where electricity is produced through various means such as fossil fuel combustion, nuclear reactions, hydroelectric dams, wind turbines, or solar panels. The generated electricity is then transmitted at high voltages (usually in the range of thousands of volts) to minimize transmission losses over long distances. The transmission system consists of high-voltage power lines, transformers, and switchgear that help in stepping up or stepping down the voltage levels for efficient transmission and distribution. At substations, the voltage is stepped down to lower levels for further distribution. Overall, the electrical distribution system forms a critical infrastructure that enables the reliable and safe supply of electricity to meet the diverse needs of residential, commercial, and industrial users. 1). In an electrical distribution system, the voltage level at which electricity is generated is typically ___________________? Low voltage Medium voltage High voltage Extra-high voltage Hint 2). The purpose of a substation in an electrical distribution system is to ___________________? Generate electricity Transmit electricity Distribute electricity Transform voltage levels Hint 3). The primary function of a circuit breaker in an electrical distribution system is to ___________________? Generate electricity Transmit electricity Control electricity flow Measure electricity consumption Hint 4). Overhead power lines in an electrical distribution system are commonly supported by ___________________? Insulators Transformers Capacitors Fuses Hint 5). The main advantage of an underground distribution system compared to an overhead system is ___________________? Lower installation costs Easier maintenance Greater reliability Higher transmission capacity Hint 6). In a radial distribution system, power flows ___________________? In multiple directions From the source to the load In a looped path Only in high voltage lines Hint 7). The device used to measure electrical energy consumption in a distribution system is called a ___________________? Transformer Circuit breaker Wattmeter Relay Hint 8). In a three-phase distribution system, the number of conductors required is ___________________? 1 2 3 4 Hint 9). The purpose of a distribution transformer is to ___________________? Generate electricity Transmit electricity Control electricity flow Step down voltage levels Hint 10). The main component of a distribution panelboard is ___________________? Circuit breaker Transformer Fuse Capacitor Hint 11). Voltage drop in a distribution system is primarily caused by ___________________? High resistance Low resistance Capacitive reactance Inductive reactance Hint 12). Which scientist is credited with the discovery of electricity? Thomas Edison Nikola Tesla Benjamin Franklin James Watt Hint 13). Who invented the alternating current (AC) system of electrical distribution? Thomas Edison Nikola Tesla Alexander Graham Bell George Westinghouse Hint 14). What is the standard frequency for AC power distribution in most countries? 50 Hz 60 Hz 25 Hz 30 Hz Hint 15). What is the formula to calculate apparent power? S = P / V S = I^2 * R S = V * I S = P * I Hint 16). What is the formula to calculate power factor? PF = P / S PF = S / P PF = P * S PF = P / V Hint 17). What is the formula to calculate three-phase power? P = √3 * V * I * PF P = √3 * V * I * PF P = V / I * PF Hint 18). What is the formula to calculate line current in a three-phase system? I = P / (V * PF) I = P / V I = P / (V * √3) I = P / (V * √3 * PF) Hint 19). What is the formula to calculate power loss in a transmission line? PL = I^2 * R PL = V * I PL = P / V PL = P * I Hint Read more about Loss Power Factor 20). What is the formula to calculate power in a three-phase system? P = V * I P = √3 * V * I * PF P = I^2 * R P = P / (V * √3) Hint 21). What is the formula to calculate voltage drop in a single-phase system? VD = I * R VD = V / I VD = P * I VD = V – I Hint 22). What is the formula to calculate power factor correction? PFC = P / S PFC = S / P PFC = P * S PFC = Q / S Hint 23). What is the formula for calculating total resistance (RT) in a parallel circuit? 1/RT = 1/R1 + 1/R2 RT = R1 + R2 RT = R1 * R2 1/RT = 1/R1 * 1/R2 Hint 24). Which formula is used to calculate line voltage (VL) in a three-phase system? VL = √3 * VP VL = VP/√3 VL = VP * √3 VL = VP/3 Hint 25). What is the formula for calculating apparent power (S) in a three-phase system? S = √3 * VL * IL S = √3 * VP * IP S = √3 * VP * IL S = √3 * VL * IP Hint Electrical Distribution MCQ for Quiz 26). The formula Z = R + jX represents __________________? Impedance Admittance Conductance Reactance Hint 27). What is the primary function of an electrical distribution system? Generating electricity Transmitting electricity Distributing electricity Storing electricity Hint 28). What is the most commonly used voltage level for residential distribution? 11 kV 33 kV 66 kV 230 V Hint 29). Which of the following is a common problem in electrical distribution systems? Overvoltage Voltage stabilization Perfect power factor Balanced loads Hint 30). What is the classification of loads based on their power consumption patterns? Active and reactive loads Residential and commercial loads Linear and non-linear loads Inductive and capacitive loads Hint 31). Which of the following is an example of a linear load? Incandescent bulb Induction motor Personal computer Electronic ballast Hint 33). What type of load is an electric motor? Resistive load Reactive load Non-linear load Active load Hint 34). Which classification of loads represents devices that produce magnetic fields? Resistive loads Inductive loads Capacitive loads Non-linear loads Hint 35). What type of load is a power factor correction capacitor? Resistive load Reactive load Non-linear load Active load Hint 36). Which classification of loads represents devices that produce harmonics? Resistive loads Inductive loads Capacitive loads Non-linear loads Hint 37). What is the classification of loads based on their usage characteristics? Residential, commercial, and industrial loads Active and reactive loads Balanced and unbalanced loads Linear and non-linear loads Hint 38). Which type of load is typically found in homes and apartments? Residential load Commercial load Industrial load Agricultural load Hint 39). What type of load is commonly found in office buildings, shops, and restaurants? Residential load Commercial load Industrial load Agricultural load Hint 40). Which type of load is associated with heavy machinery and manufacturing processes? Residential load Commercial load Industrial load Agricultural load Hint 41). What type of load is related to agricultural activities like irrigation and livestock operations? Residential load Commercial load Industrial load Agricultural load Hint 42). What is the purpose of load forecasting in an electrical distribution system? To estimate the power generation capacity required To optimize the power transmission efficiency To predict the future load demand To calculate the power factor of loads Hint 43). What is harmonics in an electrical distribution system? Fluctuations in voltage magnitude Fluctuations in frequency Distortions in the waveform of current or voltage Distortions in the phase angle of current or voltage Hint 44). What is a voltage sag in an electrical distribution system? A temporary decrease in voltage magnitude A temporary increase in voltage magnitude A permanent decrease in voltage magnitude A permanent increase in voltage magnitude Hint 45). Load modeling is important in electrical distribution systems because it helps to _________________? Predict power outages Optimize power generation Determine load characteristics Improve transmission efficiency Hint 46). In load modeling, diversity refers to _________________? Variation of loads over time Variation of loads in different locations Variation of loads based on power factor Variation of loads based on harmonics Hint 47). The load curve is a graphical representation of ___________________? Power factor variation over time Load variation over time Voltage variation over time Current variation over time Hint 48). The purpose of load forecasting is to ________________? Determine the maximum demand on the system Estimate future electricity prices Predict natural disasters affecting the system Calculate the total energy consumed Hint 49). The load duration curve is used to determine ________________? Load shedding requirements Power factor correction measures Voltage regulation techniques Load priority scheduling Hint 50). Demand response programs are designed to ________________? Reduce electricity prices Increase renewable energy generation Manage peak demand on the system Improve voltage stability Hint Electrical Distribution MCQ for Exams 51). The power factor of an electrical load determines the ________________? Reactive power consumption Apparent power consumption Real power consumption All of the above Hint 52). The main objective of voltage regulation in distribution systems is to ________________? Reduce power losses Stabilize frequency Control harmonics Maintain voltage within specified limits Hint 53). What is the load factor of an electrical distribution system? The ratio of average load to maximum demand The ratio of peak demand to minimum demand The ratio of average demand to peak demand The ratio of maximum demand to total demand Hint 54). What is the loss factor of an electrical distribution system? The ratio of power losses to total power generated The ratio of power losses to peak demand The ratio of power losses to average demand The ratio of power losses to maximum demand Hint 55). What effect does an increase in load factor have on the loss factor? Increases the loss factor Decreases the loss factor No effect on the loss factor Depends on the load type Hint 56). A distribution system has a load factor of 0.8. What is the loss factor? 0.2 0.5 1.0 1.25 Hint 57). If the load factor of a distribution system is 1.2, what can be said about the loss factor? It is greater than 1.2 It is less than 1.2 It is equal to 1.2 It cannot be determined Hint 58). How can a higher load factor benefit an electrical distribution system? Reduces losses Increases losses Has no effect on losses Depends on the load type Hint 59). Which of the following factors can influence the load factor of a distribution system? Seasonal variations Load diversity Load management strategies All of the above Hint 60). What is the relationship between load factor and energy efficiency? Higher load factor implies higher energy efficiency Higher load factor implies lower energy efficiency Load factor has no impact on energy efficiency Load factor and energy efficiency are unrelated Hint 61). What can be inferred about a system with a low load factor and high loss factor? It is energy-efficient It is energy-inefficient Load factor and loss factor are unrelated Load factor and loss factor have an inverse relationship Hint 62). Which of the following methods can help improve the load factor of a distribution system? Load balancing Load shedding Load scheduling All of the above Hint 63). The load factor of a distribution system is 0.6. What can be inferred about its utilization level? High utilization Low utilization Optimal utilization Cannot be determined Hint 64). What is the primary function of a distribution feeder in an electrical distribution system? To supply power to transformers To distribute power to end-users To regulate voltage levels To protect against overcurrent Hint 65). Which of the following is not a typical type of distribution feeder configuration? Radial Loop Mesh Star Hint 66). The distribution feeder voltage is typically _________________? High voltage Medium voltage Low voltage Extra-high voltage Hint 67). What is the typical frequency of distribution feeder voltage in most countries? 50 Hz 60 Hz 25 Hz 100 Hz Hint 68). Distribution feeders are usually operated as _________________? Single-phase Two-phase Three-phase Multi-phase Hint 69). Which of the following is a disadvantage of a radial distribution feeder? Easy to expand Higher reliability Limited fault tolerance Better voltage regulation Hint 70). A loop distribution feeder ________________? Has only one source of power Has multiple sources of power Operates at lower voltage levels Is used in industrial applications only Hint 71). The purpose of sectionalizing switches in a distribution feeder is to ________________? Protect against overvoltage Control power flow direction Isolate faulty sections Increase system capacitance Hint 72). Voltage drop in a distribution feeder can be minimized by ________________? Increasing the feeder length Decreasing the conductor size Using higher voltage levels Adding more load Hint 73). Which of the following is a characteristic of an underground distribution feeder? Lower installation cost Easier maintenance Higher fault susceptibility Hint 74). What is the primary purpose of reclosers in a distribution feeder? Maintain constant voltage Provide backup power supply Automatically restore power after a temporary fault Protect against lightning strikes Hint 75). A mesh distribution feeder configuration offers ________________? Higher reliability Lower fault current capacity Limited load capacity No voltage regulation Hint Time's up
