User:Seoul Laing Win/sandbox

Power Transients and Synchronous Machines

Soe Hlaing Win HND-1332EEE

9 April 2015

MANDALAY CHINDWIN COLLEGE

Contents Executive Summary Task How surge occurs? Surge arrestors Surge suppressor Types Of Surge arrestor Devices most effective in controlling Surge arrestor Devices most effective in controlling Comment Three lamp methods V-curve and Inverted V-curve Using MATLAB, simulate synchronous machine and attach the simulation results Conclusion References

Executive Summary The report prepared by the construction ofA Sichuan company in the PRC and Myanmar electric power authorities signed a contract in Yangon onprovision of equipment to the Myanmar side for a double circuit transmission line project.This report is mainly including problems solved for power systems to join from Shweli power plant in northern [Shan state] to Mandalay, how they operate, how they areemployed as an electrical engineer in planning and design department, which provides analysis on powers systems transients and synchronous machines used in the power system.

TASK eG (t) = Eu-1(t) eG (S) = E/ S ZR= 4ZC ZG=1/3ZC ΓR(S) = ((ZR(S))/ZC-1)/((ZR(S))/ZC+1)= (4-1)/(4+1)= 3/5 ΓS(S) = ((ZG(S))/ZC-1)/((ZG(S))/ZC+1)= (1/3-1)/(1/3+1)= - 1/3 V(x,s)=E/S [Zc/(2Zc+Zc)][(e-sx/v+ ΓR(S)e s[(x/v)-2τ])/(1-ΓR(S)ΓS(S)e-2sτ)] =E/S [Zc/(2Zc+Zc)][(e-sx/v+3/5 e s[(x/v)-2τ])/(1+3/5×1/3 e-2sτ)] =E/S [Zc/(2Zc+Zc)][(e-sx/v+3/5 e s[(x/v)-2τ])/(1+1/5 e-2sτ)] To solve1/( 1+1/5 e-2sτ), By using geometric series. 1/ 1+y = 1 - y + y2 - y3 + y4……. So, y = 1/5 e-2sτ So,1/( 1+1/6 e-2sτ) = 1 - 1/5 e2Sτ + 1/25e4Sτ –1/125 e6Sτ +………… = E/S [e-SX/V–½ es[(x/v)-2τ]– 1/5es[(x/v)+2τ]+ 1/10es[(x/v)-4τ]+1/25es[(x/v)+4τ]– 1/50es[(x/v)-6τ]+…….] Taking Inverse Laplace transform, V(x,t) = E/3 [ u-1 (t-x/v) – ½ u-1 (t+x/v-2τ) – 1/5 u-1 (t-x/v -2τ) + 1/10 u-1 (t+x/v-	4τ) + 1/25 u-1 (t-x/v-4τ) – 1/50 u-1 (t+x/v-6τ)……..]

By using Voltage division, VSs(x) = (E × ZR)/(ZG + ZR) = (E(4Zc))/(Zc/3+4Zc) = 12/13

For the Bewleylattic diagram, the vertical scale represent time and is scale in units τ, the transient time of the line. The horizontal scale represents line position x, the diagonal lines represent travelling waves. Each reflection is determined by multiplying the incident wave arriving at an end. ZR= 4ZC ZG=1/3ZC ΓR(S) = ((ZR(S))/ZC-1)/((ZR(S))/ZC+1)= (4-1)/(4+1)= 3/5 ΓS(S) = ((ZG(S))/ZC-1)/((ZG(S))/ZC+1)= (1/3-1)/(1/3+1)= - 1/3

How surge occurs? Generally, surge linking is inactive. Nevertheless, if a larger than normal voltage appears, & produces too much current, the excess current is preoccupied safely downcast the side road to ground. That means no more current than normal flows into the appliance, so it's better protection. Essentially that device is termed thevaristor (voltage-dependent resistor), made from a substance named a metal-oxide semiconductor. It is generally a bad conductor (carrier) of electricity. If an excessive voltage appears, the semiconductor in the varistor becomes a good conductor and starts to carry electricity normally. For given that the surge voltage lasts, the semiconductor channels harmful current to ground. Once things return to normal, the semiconductor switches back again. http://gemstateelectric.com/wp-content/uploads/2012/09/Services_surgetest.jpg Surge arrestors

There are many surge arrestors. They are •	The Low-voltage surge arrester is apply in Low-voltage distribution system, exchange of electrical appliances protector, low-voltage distribution transformer windings. •	Distribution arrester is applying in 3KV, 6KV, and 10KV AC power distribution system to keep distribution transformers, cables and power station equipment. •	The station type of common valve arrester can use to protect the 3 ~ 220KV transformer station equipment and communication system. •	The Magnetic blow valve station arrester applies to 35 ~ 500KV protect communication systems, transformers and other equipment. •	The Protection of rotating machine using magnetic blow valve arrester applies to protect the AC generator and motor insulation. •The Line Magnetic blow valve arrester applies to protect 330KV and above communication system circuit equipment insulation. •	The DC blowing valve-type arrester applies to protect the DC system’s insulation of electrical equipment. •	The Neutral protection arrester applies in motor or the transformer’s neutral protection. •	The Fiber-tube arrester applies in the power station’s wires and the weaknesses protection in the insulated. •	The Plug-in Signal Arrester applies to twisted-pair transmission line in order to protect communications and computer systems. •	The High-frequency feeder arrester uses to protect the microwave, mobile base stations satellite receiver, etc. •	Receptacle-type surge arrester uses to protect the terminal Electronic equipment •	Signal Arrester applies in MODEM, DDN line, fax, phone, process control signal circuit etc. •	Network arrester applies in servers, workstations, interfaces etc. •	Coaxial cable lightning arrester uses on the coaxial cable to protect the wireless transmission and receiving system. Surge suppressor

One of the most important things to prevent damage from power disturbances is to attach your electronic equipment to point-of-use surge suppressors. Surge suppressors are available at home improvement stores or at stores that sell or repair computers, stereos and other electronic devices. Here are a few tips on buying a surge suppressor: • The surge suppressor should have an indicator light or some other feature that shows you it is functioning properly. • The surge suppressor must have the three modes of protection — line to line, line to neutral, and line to ground. This will be listed in the manufacturer’s literature. • The surge suppressor should be tested and have received the UL listing for the following tests: IEEE standard 587A, 587B and UL1449. These will be verified on the back of the device by the presence of a UL sticker. • Look for substantial product and equipment damage warranties. The best units typically have an unconditional lifetime product warranty and a substantial equipment replacement warranty. • For critical computer applications where data loss can cost you money, a UPS (Uninterruptible Power Supply) should be seriously considered. Most modern households use state-of-the-art appliances and electronics. Any appliance with electronic components or microchips is highly susceptible to power spikes.

Types Of Surge arrestor Devices

The Leviton’s 50240-MSASurge arrestor is against external power surges, such as those caused by lightning or when your power company switches capacitor banks on your power grid. Leviton’s 50240-MSA is installed on the “line side” of the main service entrance, between the utility pole and your power meter, right where power comes into your house. Leviton 50240-MSA Type 1 Surge arrestor

A Leviton’s 51120-1 Panel is installed at “branch panel”. It’s termedthe branch panel because it “branches” the power coming from your service panel out to all the circuits in your house. A Leviton’s 51120-1 Panel wires directly to a dual-pole breaker in the panel, and can protect all the circuits in that panel, as well as any sub-panels that might be connected “downstream.” Leviton 51120-1 Surge arrestor

The RCA PSAPP1Ris the one you’re probably already familiar with, such as a surge strip or battery backup unit with surge protection. The RCA PSAPP1R is used at the “point of use,” meaning you plug the device(s) can want to protect directly into an outlet onthe RCA PSAPP1R, then plug the surge arrestorinto a standard power outlet. Most people useRCA PSAPP1R devices as their first and only protection for devices against power surges, but they’re actually designed to be the third and final chance to protect your device against a power surge.

RCA PSAPP1R

Surge arrestor Devices effective in controlling

The voltage or power is unexpectedly too short high voltage happens between the blink of an eye. The Voltage spikes are too high motor units can be spoiled and ruin of sensitive electronic equipment. When it fails due to lightning if we can purchase a inexpensive surge protector, we generally get one of the leads, and it is better to use it to ensure a more expensive model. Plus we need to protect the devices we use such as fax machines, computers. It is better to stop the breaker surge before it gets into the house. However the most effective surge does not provide a guarantee in case of lightning. Lightening can get into the power line and destroy switches and network ports. To stop that from happening we need to provide surge suppressor and give clean power to the products we are using. Comment

I think of two primary benefits to combining a Type 3 device (like a surge strip or a UPS unit) with a Type 2 device and/or Type 1 device. First, their effectiveness at preventing damage to your equipment is dramatically increased, because any surges on your system will be partially suppressed by the Type 2 device before it even reaches the Type 3. Second, your Type 3 surge protectors will last longer, because they’ll be required to kick in far less often, and under far less severe conditions, which will extend their service life. Because they’re so inexpensive, I recommend using some sort of Type 3 device for all your major appliances, as well as for any and all other electronic devices in your house.

Three lamp methods Illustrates a circuit used to parallel two three-phase alternators. Alternator G2 is connected to the load circuit. Alternator G1 is to be paralleled with alternator G2 Three lamps rated at double the output voltage to the load are connected between alternator G2 and the load circuit as shown. When both machines are operating, one of two effects will be observed: 1. The three lamps will light and go out in unison at a rate which depends on the difference in frequency between the two alternators. 2. The three lamps will light and go out at a rate which depends on the difference in frequency between the two machines, but not in unison. In this case, the machines are not connected in the proper phase sequence and are said to be out of phase. To correct this, it's necessary to interchange any two leads to alternator G1. The machines are not paralleled until all lamps light and go out in unison. The lamp method is shown for greater simplicity of operation. By making slight adjustments in the speed of alternator G1 the frequency of the machines can be equalized so that the synchronizing lamps will light and go out at the lowest possible rate. When the three lamps are out, the instantaneous electrical polarity of the three leads from G1 is the same as that of G2 At this instant, the voltage of G1 is equal to and in phase with that of G2 Now the paralleling switch can be closed so that both alternators supply power to the load. The two alternators are in synchronism, according to the three dark methods. 2 Synchronization of alternators The three dark method has certain disadvantages and is seldom used. A large voltage may be present across an incandescent lamp even though it's dark (burned out). As a result, it's possible to close the paralleling connection while there is still a large voltage and phase difference between the machines. For small capacity machines operating at low speed, the phase difference may not affect the operation of the machines. However, when large capacity units having low armature reactance operate at high speed, a considerable amount of damage may result if there is a large phase difference and an attempt is made to parallel the units.

Two Bright, One Dark Method Another method of synchronizing alternators is the two bright, one dark method. In this method, any two connections from the synchronizing lamps are crossed after the alternators are connected and tested for the proper phase rotation. (The alternators are tested by the three dark methods.). The connections for establishing the proper phase is rotation by the three dark methods. The lamp connections are required to synchronize the alternator by the two bright, one dark method. When the alternators are synchronized, lamps 1 and 2 are bright and lamp 3 is dark. Since two of the lamps are becoming brighter as one is dimming, it's easier to determine the moment when the paralleling switch can be closed. Furthermore, by observing the sequence of lamp brightness, it's possible to tell whether the speed of the alternator being synchronized is too slow or too fast. Synchroscope A synchroscope is recommended for synchronizing two alternators since it shows very accurately the exact instant of synchronism. The pointer rotates clock wise when an alternator is running fast and counterclockwise when an alternator is running slow. When the pointer is stationary, pointing upward, the alternators are synchronized. The synchroscope is connected across one phase only. For this reason it cannot be used safely until the alternators have been tested and connected together for the proper phase rotation. Synchronizing lamps or other means must be used to determine the phase rotation. In commercial applications, the alternator connections to a three-phase bus through a paralleling switch are permanent. This means that tests for phase rotation are not necessary. As a result, a synchroscope is the only instrument required to bring the machines into synchronization and thus parallel them; however, a set of lights is often used as a double-check system. Diagram of synchroscope connection Photo of synchroscope meter face and synchronizing lights Prime Movers In industrial applications, alternators are driven by various types of prime movers such as steam turbines, water turbines, and internal combustion engines. For applications on ships, alternators often are driven by dc motors. Regardless of how alternators are driven, speed variation is a factor in paralleling the machines. Thus, the electrician should have knowledge of speed governors and other speed regulating devices. This text, how ever, does not detail the operation of these mechanical devices. PARALLELING ALTERNATORS Since apprentices are likely to be required to parallel alternators driven by dc motors sometime in their instruction, the following steps outline the procedure for paralleling these machines. ill. 5 illustrates a typical circuit for paralleling two three-phase alternators. V-curve and Inverted V-curve V curve is the graph showing the relation of armature current as a function of field current in synchronous machines. The purpose of the curve is to show the variation in the magnitude of the armature current as the excitation voltage of the machine is varied. The synchronous motor "V Curves" shown above illustrate the effect of excitation (field amps) on the armature (stator) amps and on system power factor. There are separate "V" Curves for No-Load and Full-Load and sometimes the motor manufacturer publishes curves for 25%, 50%, and 75% load. Note that the Armature Amperage and Power Factor "V" Curves are actually inverted "V's". Assume it is desired to determine the field excitation which will produce unity power factor operation at full motor load. Project across from the unity power factor (100%) is operating point on the Y-Axis to the peak of the inverted Power Factor "V" Curve (blue line). From this intersection, project down (red line) from the full-load unity power factor (100%) operating point to determine the required field current on the X-Axis. In this example the required DC field current is shown to be just over 10 amps. Note at unity power factor operation the armature (stator) full-loadamps is at the minimum value. Increasing the field amps above the value required for unity power factor operation will cause the machine to run with a leading power factor, while field weakening caused the motor power factor to become lagging. When the motor runs leading or lagging, the armature (stator) amps are increases above the unity power factor value. To obtained V curve and Inverted V curve Stator is connected by the top three phase supply during wattmeter and ammeter. To measure the input motor of the power the method of two watt meters is used. The current line is reading by the ammeter which is the same as stator current. Voltage line is reading by Voltmeter. The figure shows an experimental setup to obtain V-curves and Inverted V-curves of synchronous motor.

http://3.bp.blogspot.com/Xuk5CnT5nVE/TnkKnBwRNWI/AAAAAAAABfs/2YZ_9qScu2A/s1600/ABB138.jpeg

1) Ia Vs If → V-curve 2) cosΦ Vs If  → Inverted V-curve The entire procedure can be repeated for various load conditions to obtain family of V-curves and Inverted V-curves. Using MATLAB, simulate synchronous machine and attach the simulation results

Conclusion

Consequently we know about the analysis on powers systems transients and synchronous machines used in the power system. References:

what is the best in surge arrestor in controlling - Google Search. 2015. what is the best in surge arrestor in controlling - Google Search. [ONLINE] Available at: https://www.google.com/search?rls=org.mozilla:en-US:official&q=what+is+the+best+in+surge+arrestor+in+controlling&ei=4yQmVf_1B8-LuATN5oEI. [Accessed 09 April 2015]. http://wiki.answers.com/Q/What_are_v_and_inverted_v_curves assessed on 13.7.2014 http://www.industrial-electronics.com/elecy3_13.html#sthash.CUgLcAYP.dpuf[Accessed 09 April 2015]. https://www.clarkpublicutilities.com/index.cfm/your.../surge Arrestor.pdf[Accessed 09 April 2015]. What's the "Best" Whole-House Surge Arrestor? - Steve Jenkins' Blog. 2015. What's the "Best" Whole-House SurgeArrestor? - Steve Jenkins' Blog. [ONLINE] Available at: http://www.stevejenkins.com/blog/2014/10/whats-the-best-whole-house-surge-arrestor/. [Accessed 09 April 2015].

 End  MANDALAY CHINDWIN COLLEGE

Next ——————————————— Introduction In this report, I will talk about the surge, different types of surge arrester, most effective type of surge arrester, three lamp methods and synchroscope, V and inverted V curves, and simulate. Problem Solving e_G (S)=E/S Z_R=4Z_C Z_G=Z_C/3 ΓR(S)= ( ZR(S)/ZC-1)/(ZR(S)/ZC+1)=(4-1)/(4+1)=  3/5 ΓS(S)= ( ZG(S)/ZC-1)/(ZG(S)/ZC+1)=(1/3-1)/(1/3+1)=-1/2 V(x,s)=E/S [Zc/(2Zc+Zc)][(e-sx/v+ ΓR(S)e s[(x/v)-2τ])/(1-ΓR(S)ΓS(S)e-2sτ)]=E/S [Zc/(2Zc+Zc)][(e-sx/v+3/5 e s[(x/v)-2τ])/(1+3/5×1/2 e-2sτ)] To solve,1/( 1+3/10 e-2sτ)

By using geometric series 1/ 1+y = 1 - y + y2 - y3 + y4……. y=3/10 e^(-2sτ) 1/( 1+3/10 e-2sτ) =1-3/10 e^2sτ+9/100 e^4sτ-27/1000 e^6sτ+⋯⋯⋯⋯ = E/S [e-SX/V– 1/2es[(x/v)-2τ]– 3/10es[(x/v)+2τ]+ 6/20es[(x/v)-4τ]+  9/100es[(x/v)+4τ]– 18/200es[(x/v)-6τ]+…….] Taking Inverse Laplace transform, V(x,t) = E/3 [ u-1 (t-x/v) – 1/2 u-1 (t+x/v-2τ) – 3/10 u-1 (t-x/v -2τ) + 6/20u-1 (t+x/v-4τ) + 9/100u-1 (t-x/v-4τ) – 18/200 u-1 (t+x/v-6τ)……..] By using Voltage division, VSs(x)=(E × Z_R)/(Z_G + Z_R )=(E×4Z_C)/(Z_C/3+4Z_C )=12E/13 Bewley lattice diagram for the line and termination

Z_R=4Z_C Z_G=Z_C/3

ΓR(S)= ( ZR(S)/ZC-1)/(ZR(S)/ZC+1)=  3/5 ΓS(S)= ( ZG(S)/ZC-1)/(ZG(S)/ZC+1)=-  1/2

Occurring of surges There are two origins sources for the surges that occur in power system, lightning surges and switching surges. Lightning surges happen when a lightning secure attacks between a cloud and objects on this planet. The effect can be direct injection of the lightning current into the objects, or indirect voltage into electrical tour. Switching surges happen when electric sufficiently are switched on or off within home, as well as by the normal functions of the usefulness. And other incident can make surges like pole broken down by vehicles. Different types of surge arrester Station Class Station class arrester is generally operated in high voltage places such as construction, electrical power plants, and substations. This arrester is designed to protect a wide range of equipment above 20 MVA range. Intermediate Class The intermediate class is designed for occupation in high pressure device of under 20 MVA range. Distribution Class Distribution class arresters is most often loaded with fluid loaded and all, discovered in the transformer. It is use in AC power distribution system to protect transformer, cable and other equipment in station. This arrestor causes in the estimation devices in less than 1000 kVA. Secondary Class Secondary class surge arresters are designed mostly protect to homes and businesses from lightning strikes. Secondary class arrester protects the least amount of systems, and generally it not protects solid state technology. Surge suppressor One of the most important things you can do to prevent damage from power disturbances is to attach your electronic equipment to point-of-use surge suppressors. Surge suppressors are available at home improvement stores or at stores that sell or repair computers, stereos and other electronic devices. Station Class	Intermediate class Distribution class Secondary class Surge suppressor

Voltage	Above 20MVA	Under 20MVA	1~1000kVA	160~170v	110~120V Application	construction, electrical power plants, and substations	Occupation in high pressure device	discovered in the transformer	protect homes and businesses	Protect electronic equipment

Most effective type of surge arrester I think the station class is best because it can protect from many voltage. By using this class the surge cannot destroy the expensive devices. Three lamp methods The three lamps will light and go out at a rate which depends on the difference in frequency between the two machines, but not in unison. In this case, the machines are not connected in the proper phase sequence and are said to be out of phase. The machines are not paralleled until all lamps light and go out in unison. The lamp method is shown for greater simplicity of operation. By making slight adjustments in the speed of the frequency of the machines can be equalized so that the synchronizing lamps will light and go out at the lowest possible rate. The two alternators are in synchronism, according to the three dark methods. Reference: http://www.industrial-electronics.com/elecy3_13.html Synchroscope A synchroscope is recommended for synchronizing two alternators since it shows very accurately the exact instant of synchronism. The pointer rotates clock wise when an alternator is running fast and counterclockwise when an alternator is running slow. When the pointer is stationary, pointing upward, the alternators are synchronized. The synchroscope is connected across one phase only. For this reason it cannot be used safely until the alternators have been tested and connected together for the proper phase rotation. Synchronizing lamps or other means must be used to determine the phase rotation. In commercial applications, the alternator connections to a three-phase bus through a paralleling switch are permanent. This means that tests for phase rotation are not necessary. As a result, a synchroscope is the only instrument required to bring the machines into synchronization and thus parallel them; however, a set of lights is often used as a double-check system. Prime Movers In industrial applications, alternators are driven by various types of prime movers such as steam turbines, water turbines, and internal combustion engines. For applications on ships, alternators often are driven by dc motors. Regardless of how alternators are driven, speed variation is a factor in paralleling the machines. Thus, the electrician should have knowledge of speed governors and other speed regulating devices. This text, however, does not detail the operation of these mechanical devices. PARALLELING ALTERNATORS Since apprentices are likely to be required to parallel alternators driven by dc motors sometime in their instruction, the following steps outline the procedure for paralleling these machines. ill. 5 illustrates a typical circuit for paralleling two three-phase alternators. V-curve and Inverted V-curve V curve is the chart displaying the regards of armature present as a operate of area present in synchronous devices. The purpose of the curve is to show the difference in the scale of the armature present as the excitation volts of the device is different. The synchronous engine "V Curves" proven above demonstrates the effect of excitation (field amps) on the armature (stator) amplifiers and on system energy aspect. There are individual "V" Shapes for No-Load and Full-Load and sometimes the engine producer posts curves for 25%, 50%, and 75% fill. Observe that the Armature Amperage and Power Factor "V" Shapes are actually upside down "V's". Assume it is preferred to figure out the area excitation which will generate oneness energy aspect operate at complete engine fill. Venture across from the oneness energy aspect (100%) is working factor on the Y-Axis to the optimum of the upside down Power Factor "V" Curve (blue line). From this intersection, project down (red line) from the full-load unity power factor (100%) operating point to determine the required field current on the X-Axis. Increasing the area amplifiers above the value needed for oneness energy aspect operate will cause the device to run with a major energy aspect, while area decline triggered the engine energy aspect to become lagging. When the engine operates major or lagging, the armature (stator) amplifiers is improves above the oneness energy aspect value. Stator is connected by the top three phase supply during wattmeter and ammeter. To measure the input motor of the power the method of two watt meters is used. The current line is reading by the ammeter which is the same as stator current. Voltage line is reading by Voltmeter. The figure shows an experimental setup to obtain V-curves and Inverted V-curves of synchronous motor. Block diagram of synchronous machine using with MATLAB simulate Synchro diagram Synchro and Synchro wave diagram Reference: https://www.clarkpublicutilities.com/index.cfm/your.../surgeProtect.pdf (Accessed on 9.4.2015) http://www.industrial-electronics.com/elecy3_13.html#sthash.CUgLcAYP.dpuf (Accessed on 9.4.2015)
 * http://electrical-engineering-portal.com/complete-overview-of-lightning-arresters-part-2. (Accessed on 9.4.2015)