An electric power system typically includes a power transmission and/or power distribution network interconnecting geographically separated regions, and a plurality of power transmission and distribution substations. The substations include equipment for transforming voltages and for switching connections between individual lines of the power system. Power generation and load flow to consumers is managed by a central Energy Management System (EMS) and/or supervised by a Supervisory Control And Data Acquisition (SCADA) system. The electric power system may also include multiple phasor measurement units (PMUs). Typically these PMUs are distributed over a large geographic area, i.e. over tens to hundreds of kilometers. These PMUs generate synchronized phasor measurements or snapshots collected across the electric power system. The phasor measurements are time-stamped complex values (amplitude and phase) of local electric quantities, such as, currents, voltages and load flows.
Each of the PMUs may forward respective phasor measurements to a central processing system. The central processing system monitors the power system based upon the phasor measurements. Since the PMUs are distributed over large geographical areas, the PMUs transmit the phasor measurements across large distances to the central processing system. The transmission of phasor measurements to the central processing system results in excess utilization of communication bandwidth and time delays. For these and other reasons, there is a need for embodiments of the present invention.
A real-time distributed wide area monitoring system is presented. The system includes a plurality of phasor measurement units that measure respective synchronized phasor data of voltages and currents, a plurality of processing subsystems distributed in a power system, wherein at least one of the plurality of processing subsystems is configured to receive a subset of the respective synchronized phasor data, process the received subset of the respective synchronized phasor data to determine respective system parameters, wherein the plurality of processing subsystems are time synchronized.
A real-time distributed wide area monitoring system is presented. The system includes a plurality of phasor measurement units that measure respective synchronized phasor data of voltages and currents, a plurality of phasor data concentrators distributed in a power transmission and distribution network, wherein at least one of the plurality of phasor data concentrators is configured to receive a subset of the respective synchronized phasor data from at least one of the plurality of phasor measurement units that is located in a local area network or a neighboring network of a receiving processing subsystem, process the received subset of the respective synchronized phasor data by executing at least one power system application to determine respective system parameters, determine a remedial action based upon the system parameters, and transmit control signals for execution of the remedial action to a control device, wherein the plurality of phasor data concentrators are time synchronized.
A power system is presented. The power system includes a plurality of phasor measurement units that measure respective synchronized phasor data of voltages and currents, a plurality of phasor data concentrators distributed in the power system, wherein at least one of the plurality of phasor data concentrators is configured to receive a subset of the respective synchronized phasor data, process the received subset of the respective synchronized phasor data by executing at least one power system application to determine respective system parameters, a central processing subsystem that is configured to receive one or more of the respective system parameters, process the received one or more of the respective system parameters to determine a remedial action; and transmit control signals to a control device for execution of the remedial action, wherein the plurality of phasor data concentrators are time synchronized.
A method for real-time distributed wide area monitoring of a power system is presented. The method includes the steps of measuring respective synchronized phasor data of voltages and currents by a plurality of phasor measurement units, receiving a subset of the respective synchronized phasor data by a plurality of processing subsystems, and processing the received subset of the respective synchronized phasor data to determine respective system parameters by the plurality of processing subsystems, wherein the plurality of processing subsystems are time synchronized.
These and other features and aspects of embodiments of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
As discussed in detail below, embodiments of the present systems and techniques include a distributed wide area monitoring system that monitors and controls a power system in real time. The distributed wide area monitoring system includes a plurality of phasor measurements units (PMUs) and a plurality of processing subsystems. In one embodiment, the plurality of processing subsystems are phasor data concentrators. The PMUs measure synchronized phasor data at respective locations in the power system. The synchronized phasor data, for example, includes phasor currents and phasor voltages. The processing subsystems receive synchronized phasor data from at least one of the PMUs. Particularly, the processing subsystems receive the synchronized phasor data from at least one of the PMUs that is located in a local area network or a neighboring network of the receiving processing subsystems. The processing subsystems determine one or more respective system parameters by processing the received synchronized phasor data. As used herein, the term “system parameters” may be used to refer to parameters that are used to determine the state, stability and faults in a power system. The determination of the system parameters locally by the processing subsystems result in reduced consumption of communication bandwidth, and reduces time delays.
As previously noted, the DWAMS 11 includes the processing subsystems 22, 24. The processing subsystems 22, 24 are distributed in the power system 10 such that the processing subsystems 22, 24 are located in neighboring networks or local area networks of at least one of the PMUs 12, 14, 16, 18, 20. The processing subsystems 22, 24, for example, may be a phasor data concentrator, a data aggregator, a data concentrator, or combinations thereof. Each of the processing subsystems 22, 24 receives at least one of the synchronized phasor data 27, 28, 30, 32, 34. As shown in
Consequent to the processing of the received synchronized phasor data 27, 28, 30, 32, 34, system parameters 38, 40 are determined. Particularly, the processing subsystem 22 determines system parameters 38, and the processing subsystem 24 determines system parameters 40. Furthermore, the processing subsystems 22, 24 may determine remedial actions based upon the system parameters. The determination of the remedial actions will be explained with an example in
Furthermore, the power system 200 includes a transmission network 214 and a distribution network 216. As shown in
Each of the PMUs 202, 204, 206 measures synchronized phasor data at respective locations. In the presently contemplated configuration, the PMU 202 measures synchronized phasor data 224, the PMU 204 measures synchronized phasor data 226 and the PMU 208 measures synchronized phasor data 228. As previously noted, the synchronized phasor data 224, 226, 228 includes phasor currents and phasor voltages. The PMUs 202, 204, 206 transmit respective synchronized phasor data 224, 226, 228 to at least one of the PDCs 208, 210 that are located in a local area network or a neighboring network of the PMUs 202, 204, 206. In the presently contemplated configuration, the PDC 208 receives the synchronized phasor data 224, 226 from the PMUs 202, 204. Furthermore, the PDC 210 receives the synchronized phasor data 228 from the PMU 206.
In one embodiment, the PDCs 208, 210 are configured to process the received synchronized phasor data 224, 226, 228 to determine system parameters. Particularly, the PDC 208 determines system parameters by processing the received synchronized phasor data 224, 226. Additionally, the PDC 210 determines the system parameters by processing the received synchronized phasor data 228. As previously noted, the system parameters may include a voltage stability index, a voltage stability margin, state of the transmission and distribution network, stability of the transmission and distribution network, oscillations in the transmission and distribution network, local oscillatory modes, faults in respective substations, or the like. In one embodiment, the PDCs 208, 210 may process the synchronized phasor data 24, 26, 28 by executing at least one power system application. Particularly, the PDCs 208, 210 determine the system parameters by executing the power system applications. The power system applications, for example, may include a small signal oscillation detection method, a phase estimation method, a voltage stability determination method, a dynamic stability determination method, a protection settings application, or the like.
In certain embodiments, the PDCs 208, 210 may determine remedial actions based upon the system parameters. Furthermore, the PDCs 208, 210 may transmit control signals to a control device 230 for execution of the remedial actions. As used herein, the term “remedial actions” may be used to refer to actions that may be executed to eliminate faults or retain the stability in a power system. The remedial actions, for example, may include load shedding, generator Re-Dispatch, system reconfiguration controls, a dynamic control of a device, and the like. Additionally, the PDCs 208, 210 may transmit control signals to a control device 230 for execution of the remedial actions. In certain embodiments, the PDCs 208, 210 may transmit the system parameters to the central processing subsystem 212. The central processing subsystem 212 may determine remedial actions based upon the system parameters. The central processing subsystem 212 may determine the remedial actions by execution of at least one power system application.
At step 306, each of the at least one processing subsystem receives the synchronized phasor data. Particularly, each processing subsystem receives synchronized phasor data from PMUs that are located in a local area network or a neighboring network of the processing subsystem. Furthermore, at step 308, each of the processing subsystems determines system parameters by processing the received synchronized phasor data. The processing subsystems process the synchronized phasor data by executing power system applications. Since the system parameters are determined by the processing subsystems that are located in the local area network or neighboring network of the PMUs, the system parameters are determined in real-time. Furthermore, at step 310, it is determined whether remedial actions are required. The requirement of remedial actions may be determined based upon the system parameters. For example, when the system parameters show that a local area network of a processing subsystem is unstable, the requirement of remedial actions may be declared at step 310. Similarly, when the system parameters show that voltage stability index at a point in a local area network is beyond a determined threshold, then a requirement of remedial actions may be declared.
At step 310, when it is determined that remedial actions are required, the control may be transferred to step 312. At step 312, one or more remedial actions may be determined. The remedial actions, for example may be determined by the processing subsystems, such as, the processing subsystems 22, 24, 208, 210. (See
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.