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State Estimaton Technique for Impedance Matching in Distribution Feeder Reconfiguration

Thesis Info

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Author

Mahmood, Tahir

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2007

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2890/1/337S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727234377

Similar


State estimation has been adopted by the power system researchers in the late 1960’s. Later on, state estimation was applied to the transmission system. Recently state estimation has become cornerstone among the modern control centers tools for the automation of distribution system. In this research work, state estimation has been implemented for automatic feeder reconfiguration. Automatic feeder reconfiguration can be accomplished by matching the impedances of two different feeders. Once the impedances are matched, static transfer switch perform the feeder reconfiguration effectively and efficiently. The liability of power distribution companies is to provide reliable and good quality power to the customers. Due to the technological advancement and the large scale production, usage of the sensitive equipment has been increased. The sensitive equipment requires quality power through reliable power delivery system. Power delivery system includes feeders and laterals to transfer power from the substation to the consumer end. As the feeders and the laterals are radially operated, therefore the chances of power interruption always exist. Power interruption may occur either due to faults or due to the maintenance or replacement of any components of the distribution system e.g. a distribution transformer. Voltage sag is another cause of interruption of sensitive equipment. To overcome this problem, sensitive equipment should be fed through two independent feeders. If the preferred feeder fails, the sensitive load should be transferred to the alternate feeder. A fast and efficient transfer switch can complete this transfer. Static transfer switch (STS) system has been developed to transfer the load from the preferred feeder to the alternate feeder when voltage sag or fault occurs on the preferred feeder. The most important parameter of the STS-system is the speed of operation or the transfer time so that the load should not be interrupted. To reduce the transfer time and hence to expedite the transfer process, it is necessary that both feeders have the same voltage angle at the point-of-installation (PoI) of the STS. If the impedances of both the feeders are identical then voltage phase difference will be zero. To match the impedance, state estimator has been designed to estimate the voltage angle of both the feeders. To mitigate the voltage phase difference, shunt capacitor has been installed and consequently the transfer time of the STS has been reduced. However, the control logic strategy of the STS-system also affect the transfer time. Two different control logic techniques namely delay logic and forced commutation technique, have been developed and simulated using PSCAD/EMTDC software. If the delay logic technique is utilized then the voltage phase angle of both feeders must be identical. The developed state estimation technique can be implemented to match the impedances and hence the voltage angle to reduce the STS transfer time. However, forced commutation technique can accommodate the phase difference by commutating the outgoing thyristor forcefully. But forced commutation technique require more components e.g. capacitor, inductor, auxiliary thyristors etc. Both techniques are implemented to solve the problems related to the feeder overloading. The problem of overloading has been solved through feeder reconfiguration. STS-system installed at critical location, transfer the sensitive load to the lightly loaded alternate feeder. This phenomenon can be termed as feeder reconfiguration using load-balancing. The development of the STS-system has solved the problem of load interruption. The reliability of the power distribution system has been improved and the sensitive load now operates without power interruption.
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67. Al-Mulk/The Sovereignty

I/We begin by the Blessed Name of Allah

The Immensely Merciful to all, The Infinitely Compassionate to everyone.

67:01
a. Blessed is HE WHO holds the reins of Sovereignty over all existence in HIS Hand,
b. and HE Manifests Sovereignty over all existence.

67:02
a. The One WHO created the phenomenon of the death and the life.
b. So that HE may test you between life and death to see which one of you would be most virtuous in deeds that pleased HIM.
c. And HE is The Almighty, The Ever-Forgiving.

67:03
a. It is also HE WHO created the seven celestial realms, one above the other in full harmony with one another.
b. You will not see any imperfection in this creation of The Immensely Merciful.
c. Then turn up your sight again!
d. Can you see any discrepancy or flaw?

67:04
a. Then turn up your sight again and again!
b. Your sight will come back to you bewildered and fatigued, unable to find any discrepancy
or flaw.

67:05
a. And, indeed, WE adorned the lowest sky to the earthly life with lamps,
b. and WE made such shooting stars/meteors that would fend off every approaching satanic evil force,
c. and, additionally, WE have prepared for them the punishment of the Blazing Fire.

67:06
a. And for those who disbelieve in their Rabb- The Lord is the punishment of Hell.
b. And it is going to be an awful and woeful destination!

67:07
a. As they would be flung into it, they will hear its furor - as it boils up,

67:08

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