In a power system, consider that all the bus's are connected with a PMU from which we get the magnitude of voltage and angle, then is there any use of performing State Estimation again?
Dear, if each bus is equipped with a PMU there is not need to perform the SE: you already have the system state.
Yes, but for a special function which is the checking of correctness and integrity of the measurements as well as for estimating the health conditions of the PMU, and WAM hardware.
I am sure PMUs are devices among others used to determine the state of network. With PMUs and other control and communication devices at each bus, you have access to real time and accurate system data which are used for state estimation.
If you have in all buses PMU why you need the use State estimation programs, since all data are in PMU and SCADA system in DATA centers ?
Agree with Mohamed EL-Shimy. State from PMU is not always perfect. Hardware, firmware, software could malfuction. Communication lines could be interfered. SE garantee you perfect power balance for other applications, a set of PMUs - not.
And you are sure that State estimation software is better then measurements of PMUs in "unknown" busbars?
Usually measurements and states are needed for dispatchers to realize the situation and for applications for on-line markets, other on-line applications. All those applications take as an input data - results of SE. SE use data from SCADA and Topology Processor. All mentioned SW applications use common information model, where Power System elements, including busbars, are known.
Dear Prof Srete,
The situation is not about which of them is more accurate. As explained by Mr. Mikhail in his two valuable comments, measurements and SE verify each other in case of installing PMUs everywhere. Consequently, the knowledge about the real-time conditions of the system will be highly reliable in comparison with the reliance on PMUs only. Fortunately, the SE methods are well developed to the level that allows the operators to check the measurements using the SE and vice versa.
In other words, one can say that neither the PMUs nor the WAM components are 100% reliable components. They may fail on the levels of subassemblies or higher. Therefore, the SE in the mentioned situation of the question can be considered as a tool for checking the overall PMUs based operation and control.
Thank you to the to prof. Mikhail and prof. Mohamed. I accept your explanation. Maybe i thought on the old way of using SE for computing unknown parameters in m -unknown busbars of n (known) +m busbars. So if in all are PMUs , SE in that situation can be considered as a tool for checking the overall PMUs based operation and control and vice versa. But I think it is high cost investments
Exactly, Prof. Serte. It will be a huge investment and may be unnecessary to install PMUs at all locations. There are many excellent research on placement optimization of PMUs. None of those I read recommended installing PMUs at all locations.
of course state estimation will be useful in correcting the error if any in measuring voltage and current using PMUs and also if there is any chance of unavailability of data (due to communication failure) at control center, state estimation values can be used in place of unavailable measurements.
I real power system or transmission system, state estimator is used in control room not only for system in responsibility of one Transmission system operator, TSO, and then it is used for wider system in neighboring TSOs. In addition, you used many measurements from distribution side or generation side. Usually in real, we do not have on all busses PMUs devices nor transmission side and even on distribution side or generators. Also on some specific and important lines we have two measurements sources from substation RTU and from others system. Therefore, for business process in control room you need to have estimator.
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