Abstract: Systems and method are disclosed for monitor long-term voltage stability in a power system by estimating post-contingency operating point(s) considering PV-PQ transitions based on the current operating point; predicting a sensitivity based Thevenin index (STI) for each contingency using the estimated operating condition; and determining a voltage stability assessment (VSA) considering N?1 contingency.

Abstract: A control system is disclosed with a control strategy for autonomous multi-bus hybrid microgrids based on Finite-Control-Set Model Predictive Control (FCS-MPC). The control loops are expedited by predicting the future states and determining the optimal control action before switching signals are sent to converters/inverters. The method eliminates PI and PWM components, and offers 1) accurate PV maximum power point tracking (MPPT) and battery charging/discharging control, 2) DC and AC bus voltage/frequency regulation, and 3) precise and flexible power sharing control among multiple DERs.

Abstract: Systems and methods for energy distribution for one or more grid-scale Energy Storage Systems (ESSs), including generating one or more time series models to provide forecasted pricing data for one or more markets, determining battery life and degradation costs for one or more batteries in or more ESSs to provide battery life and degradation costs, optimizing bids for the one or more markets to generate optimal bids based on at least one of the forecasted pricing data or the battery life and degradation costs, and distributing energy to or from the one or more ESSs based on the optimal bids generated.

Abstract: Data quality of Phasor Measurement Unit (PMU) is receiving increasing attention as it has been identified as one of the limiting factors that affect many wide-area measurement system (WAMS) based applications. In general, existing PMU calibration methods include offline testing and model based approaches. However, in practice, the effectiveness of both is limited due to the very strong assumptions employed. This invention presents a novel framework for online error detection and calibration of PMU measurement using density-based spatial clustering of applications with noise (DBSCAN) based on much relaxed assumptions. With a new problem formulation, the proposed data mining based methodology is applicable across a wide spectrum of practical conditions and one side-product of it is more accurate transmission line parameters for the energy management system (EMS) database and protective relay settings. Case studies are presented to demonstrate the effectiveness of the proposed method.

Abstract: A method and system are provided. The method includes collecting, from a plurality of phasor measurement units, a plurality of synchronized phasor measurements from different portions of a power system. The method further includes estimating, by a controller, oscillation modes of the plurality of synchronized phasor measurements. Each estimated oscillation mode specifies, for each of the plurality of synchronized phasor measurements, two or more of an amplitude, a phase, a frequency, and damping coefficients. The method also includes performing, by the controller, a modal analysis of the oscillation modes of the plurality of synchronized phasor measurements to identify critical modes based on critical mode identifying criteria. The method additionally includes constructing, by the controller based on the critical modes, a power system oscillation dampening control signal for controlling a grid-scale storage portion of the power system to dampen one or more oscillations of the power system at any given time.

Abstract: A controller used in microgrid systems that includes a primary control module and a secondary control module. The primary control module may employ a primary consensus control to control at least one of a real power and reactive power sharing in at least one distributed generator system of a microgrid. The secondary control module may employ a secondary consensus control to maintain at least one of voltage and frequency in the microgrid to a nominal value.

Abstract: Systems and methods for voltage control in an energy distribution system (EDS), including measuring voltage and current at a node in the EDS where a Grid Energy Storage (GES) device is located. A simplified equivalent of the EDS is generated by identifying parameters for the equivalent and calculating phasors corresponding to the measured voltage and current. At least one of a voltage stability index or a voltage sensitivity factor of the EDS is calculated using the equivalent, and at least one of charging or discharging of the EDS is adjusted based on at least one of the voltage stability index or the voltage sensitivity factor to regulate and stabilize voltage of the EDS.

Abstract: Methods and systems for power management include determining a voltage level of a grid; if the voltage level is below a lower voltage threshold, setting power outputs for one or more distributed generators on the grid to maximum; and if the voltage level is above the lower voltage threshold and below an upper voltage threshold, determining power outputs for one or more distributed generators on the grid using sensitivity-based distributed Q compensation.

Abstract: A method and system are provided. The method includes synchronously reconnecting a microgrid to a main grid after islanding of the microgrid. The synchronously reconnecting step includes calculating a phase angle difference between synchrophasor measurements collected from a common coupling on the main grid and synchrophasor measurements collected from a common coupling on the microgrid. The synchronously reconnecting step further includes calculating, by a controller, a frequency reference deviation based on the phase angle difference. The synchronously reconnecting step also includes adjusting a frequency of the diesel generator based on the frequency reference deviation.

Abstract: A hybrid ultracapacitor-battery energy storage system is integrated with a photovoltaic system to help solve fluctuations. A fuzzy-logic-based adaptive power management system enables optimization of the power/energy distributions and a filter-based power coordination layer serving as a rudimentary step for power coordination among the hybrid storage system and a fuzzy-logic-based control adjustment layer that keeps monitoring the operation status of all the energy storage devices, taking into account their dynamic characteristics, and fine-tuning the control settings adaptively.

Abstract: A method and system are provided. The method includes synchronously reconnecting a microgrid to a main grid after islanding of the microgrid. The synchronously reconnecting step includes calculating a phase angle difference between synchrophasor measurements collected from a common coupling on the main grid and synchrophasor measurements collected from a common coupling on the microgrid. The synchronously reconnecting step further includes calculating, by a controller, a frequency reference deviation based on the phase angle difference. The synchronously reconnecting step also includes adjusting a frequency of the diesel generator based on the frequency reference deviation.

Abstract: A method and system are provided. The method includes collecting, from a plurality of phasor measurement units, a plurality of synchronized phasor measurements from different portions of a power system. The method further includes estimating, by a controller, oscillation modes of the plurality of synchronized phasor measurements. Each estimated oscillation mode specifies, for each of the plurality of synchronized phasor measurements, two or more of an amplitude, a phase, a frequency, and damping coefficients. The method also includes performing, by the controller, a modal analysis of the oscillation modes of the plurality of synchronized phasor measurements to identify critical modes based on critical mode identifying criteria. The method additionally includes constructing, by the controller based on the critical modes, a power system oscillation dampening control signal for controlling a grid-scale storage portion of the power system to dampen one or more oscillations of the power system at any given time.

Abstract: System and methods are disclosed to handle power imbalance in one or more distributed generation (DG) units: detecting islanding at time t1; selecting Phasor Measurement Unit (PMU) measurements during a pre-defined time window [t1-?, t1]; checking the time window for an abrupt voltage change; if no sudden change of voltage is detected, determining an average value of sPMUt between t1-? and t1 and using the average as a best estimate of a system power imbalance; if a sudden change of voltage is detected at time instant t2, determining the average value of sPMUt between t1-? and t2 and using the average as a best estimate of the system power imbalance; and adjusting a power reference of the DG units based on the best estimated system power imbalance.

Abstract: Systems and methods for voltage control in an energy distribution system (EDS), including measuring voltage and current at a node in the EDS where a Grid Energy Storage (GES) device is located. A simplified equivalent of the EDS is generated by identifying parameters for the equivalent and calculating phasors corresponding to the measured voltage and current. At least one of a voltage stability index or a voltage sensitivity factor of the EDS is calculated using the equivalent, and at least one of charging or discharging of the EDS is adjusted based on at least one of the voltage stability index or the voltage sensitivity factor to regulate and stabilize voltage of the EDS.

Abstract: Systems and methods for energy distribution for one or more grid-scale Energy Storage Systems (ESSs), including generating one or more time series models to provide forecasted pricing data for one or more markets, determining battery life and degradation costs for one or more batteries in or more ESSs to provide battery life and degradation costs, optimizing bids for the one or more markets to generate optimal bids based on at least one of the forecasted pricing data or the battery life and degradation costs, and distributing energy to or from the one or more ESSs based on the optimal bids generated.

Abstract: A controller used in microgrid systems that includes a primary control module and a secondary control module. The primary control module may employ a primary consensus control to control at least one of a real power and reactive power sharing in at least one distributed generator system of a microgrid. The secondary control module may employ a secondary consensus control to maintain at least one of voltage and frequency in the microgrid to a nominal value.

Abstract: Systems and methods are disclosed for distributed cooperative control strategy between a microgrid and a main grid by providing distributed synchronization and reconnection of the distributed generators with sparse communication channels, wherein each distributed generator only receives information from neighboring generators; receiving a voltage phase angle difference and a voltage magnitude difference by a proportional integration (PI) controller to adjust the output of the distributed generator at a leader node, wherein each distributed generator shares an output frequency and a voltage with neighbors; achieving a consensus behavior between all the distributed generators; sharing power generation among the distributed generators; and synchronizing the microgrid with the main grid for a seamless reconnection after islanding.

Abstract: Methods and systems for power management include determining a voltage level of a grid; if the voltage level is below a lower voltage threshold, setting power outputs for one or more distributed generators on the grid to maximum; and if the voltage level is above the lower voltage threshold and below an upper voltage threshold, determining power outputs for one or more distributed generators on the grid using sensitivity-based distributed Q compensation.

Abstract: A method for voltage regulation of a power distribution grid includes integrating a photovoltaic (PV) system with a distributed energy storage system (ESS); monitoring voltage and current phasors at a point of common coupling (PCC) to establish a real-time Thevenin equivalent of the distribution grid; and adaptively dispatching the ESS in response to network fluctuations.

Abstract: A hybrid ultracapacitor-battery energy storage system is integrated with a photovoltaic system to help solve fluctuations. A fuzzy-logic-based adaptive power management system enables optimization of the power/energy distributions and a filter-based power coordination layer serving as a rudimentary step for power coordination among the hybrid storage system and a fuzzy-logic-based control adjustment layer that keeps monitoring the operation status of all the energy storage devices, taking into account their dynamic characteristics, and fine-tuning the control settings adaptively.