Question

Can someone help me make this basic feasibilty study about Electrical System Design particular on System Planning. following these...
1. Basic Design Considerations
2. Planning guide or the supply and distributuion system
3. Power System Modernization
4. Voltage Consideration
5. Voltage Control In Electricl Power Systems
6. Voltage Selection
7. Voltage Drop Calculations in Locating LV/HV side
8. Calculation of Voltage Drops

Thank in advance!

Answer 1

Solution:- Generally the Electrical system design is defined as “Electrical system design is the design of electrical systems. This can be as simple as a flashlight cell connected through two wires to a light bulb or as involved as the space shuttle. Electrical systems are groups of electrical components connected to carry out some operation." And now we can write bout the considerations which are mentioned as shown below 1) Basic Design Considerations:- The function of the electric power distribution system in a building or an installation site is to receive power at one or more supply points and to deliver it to the lighting loads, motors and all other electrically operated devices. The importance of the distribution system to the function of a building makes it imperative that the best system be designed and installed. The basic principles or factors requiring consideration during design of the power distribution system include: 1. Functions of structure, present and future 2. Life and flexibility of structure 3. Locations of service entrance and distribution equipment,locations and characteristics of loads, locations of unit substations 4. Demand and diversity factors of loads 5. Sources of power, including normal, standby and emergency 6. Continuity and quality of power available and required 7. Energy efficiency and management 8. Distribution and utilization voltages 9. Busway and/or cable feeders 10. Distribution equipment and motor control 11.Power and lighting panelboards and motor control centers 12. Types of lighting systems 13. Installation methods 14. Power monitoring systems 15.Electric utility requirements These are all the basic design considerations in design of Electrical system.

2)Planning guide or the supply and distributuion system:- A successful electrical power and lighting project depends on effective planning in the form of drawings, schedules, and contract specifications. This contract documentation provides a concise picture of the objectives for the electrical project work to be done. Depending on the overall scope of the project, a design can include the following components: 1. General electrical requirements (e.g., general purpose receptades) 2. Specialized electrical requirements (e.g., spe-cialized office equipment or machinery) 3. Lighting systems 4. Electrical distribution systems And now let us define the each defined above as below 1. General electrical requirements:- General electrical requirements should be defined first on any electrical design project. General elec-trical requirements are items such as the 120-volt general purpose receptacle outlets located through-out the commercial or industrial building. These receptacles are usually not specified to serve any particular load but rather are for general purpose use such as for desktop devices, standard wall re-ceptacles, and desktop computer equipment with no special electrical requirements. 2. Specialized electrical requirements:- Certain projects may indude specialized electri-cal equipment that requires separate or dedicated electrical circuitry that serves only the specialized equipment. This equipment may be of the following types: 1.Computers and/or network servers 2. Photocopiers 3.Microwave ovens and other lunchroom ap-pliances 4. Vending machines Because of their electrical load requirements, as per the manufacturer's requirements, these pieces of equipment may require individual circuitry and special grounding methods

3. Lighting systems:- Because of their complexity, lighting systems are the part of the design process that generally requires the greatest amount of time to develop. These systems include all the lighting fixtures and their controls. Lighting systems have very detailed requirements as per the NEC and require documentation showing that the system incorporates all required energy-saving technologies. 4. Electrical distribution systems:- An electrical distribution system is the installed equipment that provides for the distribution of elec-trical wiring throughout the facility. It includes the main switchboard, which receives the power source from the serving utility, and all the associated components such as panelboards that distribute all the required branch circuits through-out the facility. Part of the process of designing the distribution system is calculating the facility's amperage load and short-circuit val-ues; these calculations determine the total electrical demand requirements of the facility based on the individual parts of the electrical distribution system These are the power planning considerations in Electrical syatem design 3)Power System Modernization:- The U.S. electric power system has provided highly reliable electricity for more than a century, yet much of the current electric grid was designed and built decades ago using system design models and organizational principles that must be restructured to meet the needs of a low-carbon, digital economy. The traditional architecture was based on large-scale generation remotely located from consumers, hierarchical control structures with minimal feedback, limited energy storage, and passive loads. This traditional system was not designed to meet many emerging trends, such as greater adoption of relatively low inertia generation sources, growing penetration of distributed generation resources, and the need for greater resilience. As described in several recent studies, a modern grid must be more flexible, robust, and agile. It must have the ability to dynamically optimize grid operations and resources, rapidly detect and mitigate disturbances, integrate diverse generation sources, integrate demand response and energy-efficiency

resources, enable consumers to manage their electricity use and participate in markets, and provide strong protection against physical and cyber risks. These features must be incorporated as the electric grid transitions from the traditional design to the design of the future. This traditional system was not designed to meet many emerging trends, such as greater adoption of relatively low inertia generation sources, growing penetration of distributed generation resources, and the need for greater resilience. As described in several recent studies, a modem grid must be more flexible, robust, and agile.It must have the ability to dynamically optimize grid operations and resources, rapidly detect and mitigate disturbances, integrate diverse generation sources, integrate demand response and energy-efficiency resources, enable consumers to manage their electricity use and participate in markets, and provide strong protection against physical and cyber risks. These features must be incorporated as the electric grid transitions from the traditional design to the design of the future. The electric power grid is evolving to include more distributed control; two-way flows of electricity and information; more energy storage; and new market participants, including consumers as energy producers. 4) Voltage Consideration:- The power station generated direct current and operated at a single voltage. Direct current power could not be transformed easily or efficiently to the higher voltages necessary to minimise power loss during long-distance transmission, so the maximum economic distance between the generators and load was limited to around half a mile (800 m). Most refrigerators, air conditioners, pumps and industrial machinery use AC power whereas most computers and digital equipment use DC power (digital devices plugged into the mains typically have an intemal or external power adapter to convert from AC to DC power). AC power has the advantage of being easy to transform between voltages and is able to be generated and utilised by brushless machinery. DC power remains the only practical choice in digital systems and can be more economical to transmit over long distances at very high voltages The ability to easily transform the voltage of AC power is important for two reasons: Firstly, power can be transmitted over long distances with less loss at higher voltages. So in power systems where generation is distant from the load, it is desirable to step-up (increase the voltage of power at the generation point and then step-down (decrease) the

voltage near the load. Secondly, it is often more economical to install turbines that produce higher voltages than would be used by most appliances, so the ability to easily transform voltages means this mismatch between voltages can be easily managed. A final consideration with loads has to do with power quality. In addition to sustained overvoltages and undervoltages (voltage regulation issues) as well as sustained deviations from the system frequency (frequency regulation issues), power system loads can be adversely affected by a range of temporal issues. These include voltage sags, dips and swells, transient overvoltages, flicker, high-frequency noise, phase imbalance and poor power factor. Power quality issues occur when the power supply to a load deviates from the ideal: For an AC supply, the ideal is the current and voltage in-sync fluctuating as a perfect sine wave at a prescribed frequency with the voltage at a prescribed amplitude. For DC supply, the ideal is the voltage not varying from a prescribed level. Power quality issues can be especially important when it comes to specialist industrial machinery or hospital equipment. 5) Voltage Control In Electric Power Systems:- Before learning the methods of voltage control in power system, we must first understand why do we need to control voltage. In power systems, voltage is supposed to be constant which is obviously not. So we have to control it in such a way that it remains constant. But why does the voltage need to be constant at all? Because, most of the devices, apparatus, electrical machines, consumer appliances etc. are all designed to work at a specified voltage. Wide variations of voltage may cause errors in operation, malfunctioning or performance deterioration. It is desirable that the consumers receive power at substantially constant voltage. In many countries, including India, the statutory limit of voltage variation is 16% of the declared voltage at consumers' end. Therefore, it is important to apply certain techniques, certain methods to control the power system voltage to keep it constant. Following are the methods of voltage control in power system. Methods of voltage control in power system:- 1. Using excitation control or voltage regulators at generating stations 2. By using tap changing transformers 3. Using induction regulators 4. By using shunt reactors

L 5. By using shunt capacitors 6. Using synchronous condensers 1.Excitation control or voltage regulators at generating stations:- Induced emf (E) of a synchronous generator depends on the excitation current (field current). The terminal voltage of an altemator can be given as V=E - IZ. As the load current, and hence the armature current, increases, voltage drop in the armature also increases. The field current must be increased to compensate this voltage drop, such that the terminal voltage is at the target value. For this purpose, altemators are provided with excitation control or automatic voltage regulator systems. There are two main types of automatic voltage regulators (AVR): 1.Tīrril regulator 2.Bidwn-Boveri regulator An automatic voltage regulator detects the terminal voltage and compares it with the reference voltage. The difference between detected voltage and given reference voltage is called as the error voltage. The regulator then controls the excitation voltage of the alternator to cancel out the error voltage. Thus, an automatic voltage regulator controls the voltage by controlling the excitation. Excitation control method is satisfactory only for short lines. For longer lines, the terminal voltage of alternator has to be varied widely for the voltage at far ends to remain constant. Obviously, this method is not feasible for longer lines. 2.By using tap changing transformers:- The voltage control in transmission and distribution systems is usually obtained by using tap changing transformers. In this method, the voltage in the line is adjusted by changing the secondary EMF of the transformer by varying the number of secondary tums. Secondary voltage of a transformer is directly proportional to the number of secondary turns. Thus, the secondary voltage can be adjusted by changing the turns ratio of the transformer. Secondary number of turns can be varied with the help of tappings provided on the winding. Basically, there are two types of tap changing transformers. 1.off-load tap changing transformers 2.on-load tap changing transformers

3. Voltage control using off-load tap changing transformers:- In this method, the transformer is disconnected from the supply before changing the tap. Off load tap changing transformers are relatively cheaper. But the main drawback with them is that the power supply is interrupted while changing the tap. 4. Voltage control using on-load tap changing transformers:- In modem power system, continuity of the supply is important. Therefore, on-load tap changing transformers are preferred to control the voltage. 5. By using induction voltage regulators:- An induction regulator is basically an electrical machine somewhat similar to an induction motor except that the rotor is not allowed to rotate continuously. The rotor of induction regulator holds primary excitation) winding which is connected across (parallel) the supply voltage. The stationary secondary winding is connected in series with the line which is to be regulated. From electrical point of view, it is immaterial whether primary winding is rotating or secondary winding is rotating. The magnitude of voltage in the secondary winding depends upon its position with respect to the primary winding. Thus, the secondary voltage can be adjusted by rotating the primary winding. Induction voltage regulators were used to control voltage of electrical network in earlier days, but they are now replaced by tap changing transformers. 6. Voltage control by using shunt reactors:- Shunt reactors are basically inductive elements that are provided at sending end and receiving end of long EHV and UHV transmission lines. When a transmission line is not loaded or lightly loaded, the line capacitance predominates and receiving end voltage becomes greater than the sending end voltage. This effect is known as Ferranti effect. In such situation, shunt reactors are switched in the line. Shunt reactors compensate the line capacitance and, hence, control the voltage. 7. Voltage control by using shunt capacitors:- Shunt capacitors are usually installed at the receiving end substations or near industrial loads. Most of the industrial loads draw inductive current and therefore the power factor is lagging (usually 0.3 to

0.6 lag). The line experiences IX, drop due to this lagging current. Switching in shunt capacitors compensate this inductive reactance, thereby, decreasing the IX, dip. Thus, shunt capacitors can be used to control the line voltage when the load is highly inductive. 8. Voltage control by using synchronous condenser:- A synchronous condenser is basically an over-excited synchronous motor running on no-load. Synchronous condensers are also called as synchronous phase modifiers. A synchronous condenser is located near the load end and can inject or absorb reactive power. And, thus, a synchronous phase modifier improves the voltage profile. This is the all information about voltage control methods in electrical system design 6. Voltage Selection:- 250 V or less - LV 251 V to 650 V - MV 651 V to 33 kV - HV Above 33 kV - EHV Distribution System:- Single phase AC supply using a 2-wire system Three phase AC aupply using a 3-wire system Supply of three phase and neutral using a 4-wire system DC supply:- A two wire system at 220V A three wire system with 440 V between the two outer conductors and 220V between the outer conductors and center wire. Supply Voltage:- - Single Phase : 240V,50 Hz, 2 wire -Three Phase : 415V ,50 Hz, 4 wire Consumers with load requirement more than 250 kVA are provided with supply at high voltage with a substation installed in the consumers premisis where voltage is stepped down to 415/240 V

7. Voltage Drop Calculations in Locating LV/HV side:- To calculate voltage drop: 1. Multiply current in amperes by the length of the circuit in feet to get amper-feet. Circuit length is the distance from the point of origin to the load end of the circuit. 2. Divide by 100. 3. Multiply by proper voltage drop value in tables. Result is voltage drop. Voltage Regultion is to maintain a fixed voltage under different load. Voltage regulation is limiting factor to decide the size of either conductor or type of insulation. In circuit current need to be lower than this in order to keep the voltage drop within permissible values. The high voltage circuit should be carried as far as possible so that the secondary circuit have small voltage drop. % Voltage Regulation = (1.06 x P x L x PF)/(LDF x RC x DF) P-Total Power in KVA L - Total Length of Line from Power Sending to Power Receiving in KM. PF - Power Factor in p.u RC- Regulation Constant (KVA-KM) per 1% drop. RC = (KV x KV x 10)/( RCosó + X sino) LDF - Load Distribution Factor. LDF = 2 for uniformly distributed Load on Feeder. LDF > 2 If Load is skewed toward the Power Transformer. LDF = 1 To 2 If Load is skewed toward the Tail end of Feeder DF - Diversity Factor in p.u

L The voltage variations in 33 kV and 11kV feeders should not exceed the following limits at the farthest end under peak load conditions and normal system operation regime. Above 33kV (-) 12.5% to (+) 10%. • Up to 33kV (-) 9.0% to (+) 6.0%. • Low voltage (-) 6.0% to (+) 6.0% In case it is difficult to achieve the desired voltage especially in Rural areas, then 11/0.433 kV distribution transformers (in place of normal 11/0.4 kV DT's) may be used in these areas. This is the information about voltage drop at Hvand LV sides 8. Calculation of Voltage Drops:- Voltage drop means the reduction in voltage or voltage loss. Due to the presence of the impedance or passive elements there will be some loss in voltage as the current moves through the circuit. That is, the energy supplied from the voltage source will get reduced as the current flows through the circuit. Too much voltage drop may result in damage and improper function of the electrical and electronics apparatus. Basically, the voltage drop calculation is done by Ohm's law. Voltage Drop in Direct Current Circuits:- Working with single phase, three-phase and DC (direct current circuits) and you quickly need to reference formulas for voltage drops and power calculations for a given conductor? The table below provides a quick reference for these calculations. Voltage Drop and Power Calculation Formulas For Single Phase Circuits:- Voltage Drop - AV=2*I*L*(Cos$+xSino) % Voltage Drop - % AVEAVVr*100

L Voltage Drop and Power Calculation Formulas For Three-Phase Circuits:- Voltage Drop - AV=3-V*I*L*(Cos$+xSino) % Voltage Drop - % AV=AWp*100 Voltage Drop and Power Calculation Formulas For Direct Current (DC) Circuits:- Voltage Drop - AV=2*I*L* % Voltage Drop - % AV-AVVr*100 Where L = Total length of conductor r=Resistance of conductor per unit length x= Reactance of conductor per unit length AV = Voltage drop P = Active power Q = Reactive power I = Current These are the requirements according to the given question.