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Voltage and current waveforms contain the most authentic and granular information on the behaviors of power systems. In recent years, it has become possible to synchronize waveform data measured from different locations. Thus large-scale coordinated analyses of multiple waveforms over a wide area are within our reach. This development could unleash a set of new concepts, strategies, and tools for monitoring, protecting, and controlling power systems and apparatuses. This paper presents an in-depth review and analysis of the advancements in synchronized waveform data, including measurement devices, data characteristics, use cases, and comparisons with synchrophasor data. Based on the findings, five strategies are proposed to discover and develop synchronized waveform based applications over multiple application areas. The paper also presents three complementary measurement platforms and two data screening algorithms for application implementation. It further discusses committee activities and standard developments useful to explore the full potential of the data. [ABSTRACT FROM AUTHOR]

Identifying sources of subsynchronous resonance (SSR) is crucial for understanding and mitigating incidents. Recent studies have shown that SSR impedance and power are effective indicators that can identify an SSR source. However, the calculation of two indexes requires SSR voltage and current phasors as the inputs, which are not directly available from existing online monitoring systems. To address this issue, this paper presents a novel method to calculate SSR impedance/power based on synchrophasors provided by a wide-area monitoring system. As a result, the online detection of SSR sources is enabled. Through mathematical derivation, it is revealed that a synchrophasor under SSR is dominated by four modes: two from the fundamental frequency and two from the SSR frequency. The problem thus can be transformed to a modal parameter extraction (MPE). Two classic MPE algorithms, Prony analysis and the matrix pencil method, are employed in this paper to extract the SSR parameters and calculate the SSR impedance/power. Their performances are verified using synthetic signals and electromagnetic transient simulations. Furthermore, the method is applied to an actual SSR incident involving 23 wind farms. The findings suggest that 17 of 23 wind farms did not contribute negative damping to the oscillation. [ABSTRACT FROM AUTHOR]

Harmonic phasor estimation can be used both in power system protection and monitoring applications, such as islanding detection, high-impedance fault location, and harmonic state estimation. A key challenge for harmonic phasor estimation is that different harmonics have different harmonic frequency bandwidths. As a result, a harmonic phasor estimator (HPE) that can adapt to such variations is needed. Although the sinc interpolation function-based estimator (SIFE) has such ability, it has disadvantages that: 1) it needs numerous simulations to select the model parameter and 2) it cannot obtain zero-error results under nominal frequency condition. In this article, a novel HPE is proposed based on the frequency-domain sampling theorem, where the harmonic phasor is modeled based on several imaginary exponential functions. The proposed HPE is compared with the SIFE in frequency response, model parameter selection scheme, and simulation tests. The results show that the proposed HPE has the following three advantages: 1) it has an easier scheme for model parameter selection; 2) it has zero-error results under nominal frequency condition; and 3) it has higher accuracy under harmonic frequency deviation and harmonic modulation conditions. [ABSTRACT FROM AUTHOR]

With the increasing penetration of converter based renewable generators into the modern power systems, subsynchronous control interaction (SSCI) phenomenon is jeopardizing the equipment safety and system stability. For the analysis and prevention, it is critically important to identify the source of such sub/super-synchronous oscillation caused by the SSCI. This article first develops three criteria for determining the SSCI sources based on sub/super-synchronous powers and impedances. One of the criteria takes into account the coupling effects between sub- and super-synchronous frequencies. Then, a general framework for the SSCI source identification is established, which is based on wide-area monitoring of the sub/super-synchronous power flows obtained from measured voltage and current phasors. Finally, the proposed identification criterion and framework are verified on the electromagnetic transient model of the Hami wind power system, which has experienced an actual SSCI incident. The results indicated that the wind farms based on type-4 wind turbine generators were the main sources of oscillation, while nearby thermal power plants were the sinks. [ABSTRACT FROM AUTHOR]

The existing phasor‐measurement unit (PMU) and wide‐area measurement system (WAMS) based on thefundamental synchrophasors are insufficient to accurately capture the dynamicsof sub/super‐synchronous resonance or oscillation (SSR/SSO). To address thisissue, this study proposes a new method for the simultaneous and precisemeasurement of the fundamental and multiple sub/super‐synchronous harmonicphasors. It improves the classic discrete Fourier transform (DFT)‐based methodby adding adaptive frequency detection, modal filtration and phasor correctionand compensation. Thus, in the context of SSR/SSO, the phasors of bothfundamental and interharmonic components can be precisely obtained at local PMUsand the control/data centre of WAMS. The basic procedures and the prototypeimplementation of the method have been elaborated, and the performance has beenexamined with simulation signals as well as the field data recorded from anactual SSO incident. The results have verified its high precision, noiseimmunity and fast response. [ABSTRACT FROM AUTHOR]

Electromagnetic transient (EMT) and transient stability hybrid simulations are predominantly used to analyze the interactions between HVDC systems and the ac grids. However, the dynamics of the converters will be greatly affected by the waveforms of adjacent ac systems. Waveform distortion as well as time delay caused by interfacing can significantly increase interface errors, resulting in the decrease of the overall accuracy of the simulations. To solve such problems, a dynamic phasor based interface model (DPIM) is proposed in this paper to improve the accuracy of interfaces, especially when the fault occurs near the converters. In doing so, the whole system is partitioned into three parts: the transient stability (TS) subsystem, the EMT subsystem, and the DPIM. During each iteration, the interfaces between the TS subsystem and DPIM are represented by their Norton equivalents at the fundamental frequency and Thevenin equivalents in the dynamic phasor form. Similarly, the interfaces between DPIM and EMT subsystems are represented by their three-phase Norton equivalents and Thevenin equivalents in dynamic phasors, respectively. The effectiveness concerning the accuracy and the efficiency of the proposed method is validated by simulating a practical HVDC Project. [ABSTRACT FROM AUTHOR]

Due to the interactions between the generators/power electronic devices and the grids, wideband oscillation events have occurred frequently in renewable power systems with frequencies from several Hz to several kHz. Wideband oscillation monitoring techniques have been emerging in recent years to identify and analyze these events. Unlike existing review papers that concentrate on fundamental synchrophasor technology, this paper reviews the wideband monitoring technology. Specifically, the synchronized wideband phasor measurement techniques and the synchronized waveform measurement techniques are first reviewed. Next, the measurements' applications on wideband oscillation identification, early warning, and mitigation, and other applications in power system operation are carefully introduced. Also, the challenges in wideband phasor estimation and waveform data compression are discussed, and possible solutions are highlighted. Finally, future research opportunities on new applications in wideband oscillation and power quality are highlighted. [Display omitted] • This review focuses on wideband phasor and waveform measurements and applications. • This is the first paper that concentrates on the wideband oscillation monitoring. • The challenges on wideband measurements are discussed. • Future researches on new applications of wideband measurements are highlighted. [ABSTRACT FROM AUTHOR]

• A multi-modal damping control (MADC) is proposed to damp multiple oscillation modes independently. • A general design framework for damping multiple oscillation modes is given. • MADC is validated to damp sub-synchronous and super-synchronous oscillations in Type-4 wind farms. Type-4 wind farms connected to weak AC grids have the risk of sub-synchronous oscillation/interaction (SSO/SSI) with multiple oscillation modes, which can lead to unplanned outages and system destabilization. This paper first presents the magnitude and frequency characteristics of the oscillations followed by the control design requirements. Then, it gives a general design of grid-side multi-modal adaptive damping control (MADC) to stabilize multiple oscillation modes. The MADC utilizes an FFT-based inter-harmonic phasor measurement algorithm, which can detect and track multiple oscillation modes simultaneously. The MADC uses bus voltages and line currents as inputs to extract and control each oscillation mode without considering the coupling of the modes due to the frequency coupling effect. The unstable modes are stabilized by injecting phase-shifted currents with multiple frequencies such that the impedance response of the whole system around the concerned frequencies is reshaped. Notable features of the proposed damping control include automatic and independent detection, tracking and suppression of multiple oscillation modes. The proposed MADC's damping performance is validated through extensive electromagnetic transient (EMT) simulations of type-4 wind farms connected to a weak ac grid causing super-/sub-synchronous oscillations. The system model and the proposed damping control are designed and tested in commercial EMT software. [ABSTRACT FROM AUTHOR]

Short‐term voltage stability (STVS) issue poses a significant threat to receiving‐end power systems with high penetration of induction motors. To improve STVS of a receiving‐end system in a limited geographic area, this study proposes a local‐area STVS control system (LVCS). LVCS consists of phasor measurement units (PMUs), a local‐area centralised controller (LCC), generator‐level actuators (GLAs) and high‐speed communication networks. The PMUs or GLAs are pre‐deployed according to the observability or controllability of STVS. LCC receives and processes voltage measurements from PMUs to generate supplementary excitation control signals (SECSs). The SECSs are next forwarded to and executed by GLAs. Simulation studies on a practical receiving‐end system in China Southern Power Grid demonstrate that: once the target system suffers a serious fault, LVCS can 'feel' the voltage sag at critical buses and enforce the excitation control of generators to inject more dynamic var into the receiving‐end system. As a result, the increasing var demand is met locally and STVS can be improved considerably. Time delay caused by synchrophasor transmission has also been considered in the design of LVCS to make it feasible in practice. Thus, the proposed LVCS offers a new and effective solution to the STVS problem. [ABSTRACT FROM AUTHOR]