Analysis of Flywheel Energy Storage Devices
Added on 2021-04-16
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Electrical power 1ELECTRICAL POWER By NameCourseInstructorInstitutionLocationDate
Electrical power 2 Question three High Voltage Direct Current has some comparison with the High Voltage Alternating Current isbasically done by the use of the advantages and disadvantages as seen in the analysis below;Advantages of HVDC over HVAC i. There is reduced cost of transmission since there are only two cables used for transmission as compared to three or four cables of transmission used in HVAC ii.Transmission losses are highly reduced since there is no reactive power in HVDC. iii.Because of high transmission voltage, in the same power the current is less, therefore the power loss due to I2R is very small[ CITATION Ang12 \l 1033 ]. iv.When there are faults, power levels in HVDC system can be easily be managed electronically v.HVAC has skin effect which is lacking in the HVDCvi.The cost of installation is very small as compared to HVAC since there are only two cables required for the HVDC vii.HVDC is preferred in power transmission via cables because it needs no reactive power and no charging current. viii.It is possible to connect two AC systems with different frequencies using HVDC transmission line and this is not possible in HVAC.Disadvantages of HVDC over HVAC i. It is very complex to operate and design multi-terminal HVDC system as compared to AC systems. ii.Power faults always occur on the inverter output side in the HVDC transmission system.iii.It is very difficult and very complex to ground the Dc power transmitted through HVDC. iv.There is radio noise which is caused by high-frequency constituents present in DC transmission systems[ CITATION Jer \l 1033 ].
Electrical power 3v.There is the high cost of inverting and converting components needed for the HVDC transmission, therefore, it is uneconomical.vi. There is high installation cost due to the additional filters needed in various stages of HVDC transmission systems[ CITATION Chr121 \l 1033 ]. vii.The movement of current via the ground in monopole systems can lead to theelectro-corrosion of underground metal installations, especially in pipelinesQuestion four Power quality is in many cases defined as the ability of the electrical grid to supply a very stableand a clean power flow as a perfect power is constantly present and has a pure noise-free sine wave shape, and is continually within frequency tolerance and voltage[ CITATION Ang12 \l 1033 ]. But in most cases, there are some power quality parameters. And these power quality parameters include the following;i.Harmonic ii.Reactive poweriii.Flickeriv.Transients v.Voltage variation vi.Oscillationvii.Network unbalance These parameters result in excessive losses and disturbances in the power quality. i.Harmonic Several supplies of frequency, for example, the fifth harmonic may be about 250 Hz when the supply frequency is 50 Hz which is caused by power electronic loads like undisputable power supply (UPS) and variable power supply[ CITATION Mon13 \l 1033 ]. The pollution caused by the harmonic creates extra stress on the network and ensures installation run less efficacy[ CITATION Sam12 \l 1033 ]. The pollution due to harmonic is always characterized by the THD (total
Electrical power 4harmonic disturbance). And this THD is the same to the ratio of the RMS harmonic content to the fundamental[ CITATION Ire16 \l 1033 ]. THDV = √VRMS2−V12V1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1The equation 1 above can be simplified further to equation 2 as seen below THDV= √∑K−2Vk2V1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Historically passive filters are being suggested to help mitigate this pollution of harmonic. While the active filter which is based on the power electronics mitigation in low voltage uses[ CITATION Dav13 \l 1033 ]. This can be illustrated in the diagram below;Fig 1: Showing the harmonic pollution [ CITATION Sam12 \l 1033 ]As a whole, minor frequency harmonics are highly severe than a higher frequency, since there is more energy in the lower frequencies than in higher frequency[ CITATION Mic121 \l 1033 ]. Nevertheless, high harmonic distortion may result in glitches with control equipment and communication.
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