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The Monte Carlo method (MCM) is the most widely used statistical approach to evaluate the lightning performance (LP) of overhead transmission lines (OTLs). However, the MCM has a very high computational burden, making LP studies time consuming. To overcome this difficulty, this letter proposes a new alternative approach for calculating the the lightning overvoltages (LOs) using the unscented transform

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This article proposes a graphical method to evaluate the feasibility of intentional islanding of distributed synchronous generators. The approach is based on the combination of the performance and restriction curves. These curves are based on the islanding detection capability of the frequency-based protection at the point of common coupling and on the generator protection at its terminals. When relating

The availability of accurate and cost-effective solutions for the real-time monitoring of overhead covered conductors (CC) is now becoming an important tool for the reliability and condition assessments of this class of electrical lines. This is even more crucial due to the possibly large number of conductors and the wide geographical spread of the electrical network. This letter proposes a smart and

Wide-area fault location (WAFL) refers to the estimation of fault distance on the faulted line using PMU data. A system of linear equations is formulated for WAFL, taking advantage of both voltage and current synchrophasors. This results in a generalized closed-form solution for the fault distance using the weighted least-squares method. The main contribution of the letter is the rigorous derivation

Inverter-based resources are proliferating in distribution systems across the globe, along with battery energy storage systems. This in part is attributed to a descending trend observed in their costs. These inverter-based resources, however, create new problems for electrical utilities planners and engineers. One such issue is how to measure, test, and manage load rejection overvoltage. This phenomenon

The presence of overvoltage can cause the insulation deterioration and excite the partial discharges (PD) in gas-insulated switchgear (GIS), and it is necessary to detect the overvoltage and PDs simultaneously to evaluate the insulation performance. A novel GIS internal composite sensor for PD detection and overvoltage measurement is proposed in this paper. The proposed sensor is mainly formed with

This letter presents a novel parameter-free fault location algorithm for a two-terminal single circuit untransposed line with flat and delta conductor configurations while considering unsynchronized measurements. It improves the existing works by introducing unequal angles of synchronism mismatch in pre-fault and fault conditions. EMTP-RV based simulation results corroborate the validity and accuracy

The intermittent nature of renewable energy sources (RESs) hamper their integration to the grid. The stochastic and rapid-changing operation of RES technologies impact on power equipment reliability. Transformers are key integrative assets of the power grid and it is crucial to monitor their health for the reliable integration of RESs. Existing models to transformer lifetime estimation are based on

The traditional fault control strategy of converter-interfaced renewable energy sources (CIRESs) may bring about a lower sensitivity level or misoperation of fault component-based directional elements. To overcome this problem, a new control scheme is proposed to adjust sequence impedance angles of CIRESs by computing suitable current references of the CIRES controller. Meanwhile, these current references

With the coupling of the DC metro network and urban power grid, the DC metro stray currents flowing into transformers have caused serious DC bias. There is, therefore, a need to evaluate transformer neutral direct currents caused by the DC metro stray current. To achieve this, an evaluation model considering the coupling of DC metro network and urban power grid is proposed. In the modeling principle

This paper discusses the series of tests performed to demonstrate that for SF 6 and other gas switchgear, the inrush current frequency on capacitor energization or pre-restrike is much less important than the current magnitude and often does not need to be limited. Also, the inrush current magnitude alone may not need to be limited. The limiting parameter is the ICI (Inrush Current Integral) during

The existing standard current-temperature calculations for overhead line (OHL) conductors have been adequate for conventional conductors and their operating temperatures. However, these calculations make assumptions and include simplifications about conductor geometry and aero-thermal-dynamics, introducing an error in the High-Temperature Low-Sag conductors operating temperatures. To quantify the error

This article presents a cascaded packed U cell (CPUC) converter tied to solar photovoltaic (PV) system. Here, a set of 25 levels in output voltage provides excellent harmonic performance and give a new approach for the solar-grid tied system. The nearest level modulation strategy (NLMS) is considered for fundamental switching at 50 Hz. One solar PV source is used at the high side directly connected

Cascading failures of relay operations in power systems are inherently linked with the propagation of wide-area power system blackouts. In this paper, we consider a power system cascading failure as an indicator matrix encoding: what power system relays operated within a cascading failure inherently capturing the component and the sequence of tripping events. We propose that this matrix may then be

This paper proposes an optimization-based size reduction methodology for Modular Multilevel Converters (MMC), focusing on minimizing the converter's sub-module capacitor $C_{SM}$ . The analysis is performed considering both the converter's current and voltage limitations and the Transmission System Operator (TSO) Fault Ride Through (FRT) requirements. By means of a steady-state analysis, the time-domain

Regarding power system dispatch decisions, the current-carrying limits of transmission lines in each dispatch period in the look-ahead time horizon should be represented by the intra-period minimum thermal rating (IMTR) for the sake of security. In this paper, the IMTR prediction issue of the overhead conductor is raised, and the predictability of the IMTR is investigated. Specifically, for the overhead

When the microgrid operates in grid-tied mode, the voltage ride-through (VRT) capability presents a challenge in its inverter controller design. This letter proposes an effective method to support the VRT capability of an inverter-based grid-tied microgrid during grid fault. In addition, the inverter control is implemented by a combined method to mitigate its output current harmonics under normal or

The aim of this paper is to develop a detailed model and investigate its importance for capturing load behavior in both dynamic and harmonic simulations. A detailed electromagnetic transient (EMT) type model of a mixed residential-commercial load is developed using a component-based technique, and its dynamic characteristic is validated against existing field measurements. The model is subsequently

In an islanded hybrid ac/dc microgrid (IHMG), ac and dc subgrids are connected via interlinking converters (ICs). For reliable operation of an IHMG, achieving distributed generators’ power sharing (DGPS) throughout the entire IHMG and ICs’ power sharing (IPS) is the main objective in an IHMG. To improve efficiency of an IHMG, minimizing operating costs of DGs is required and thus cost-minimized DGPS

The original model-based wide-area damping control (WADC) is difficult to obtain good damping performance due to the complex structure of interconnected power systems. In this paper, an improved data-driven model-free adaptive control (ID-MFAC) algorithm is proposed to design WADC for interconnected power systems with stochastic communication delays. First, the multiple-input multiple-output power

Control of circulating current can help modular multilevel converters (MMCs) improve the internal performance, but only the conventional circulating current suppression control has been considered in impedance models to investigate MMC-grid interactions. In this paper, the sequence impedance responses of circulating current injection methods based on instantaneous information are modeled for stability

Situational awareness (SA) is critical to properly operating active power distribution systems during normal and outage conditions. Appropriate SA tools should provide an accurate estimate of system voltage and current variables, the operational network topology, and the power injections from distributed energy sources (DERs), including behind-the-meter (BTM) photovoltaics (PVs). Obtaining an accurate

In the digital era, the secondary equipment of power system is becoming more and more sensitive to electromagnetic interference. Gas insulated switchgear (GIS) in substations will generate very fast transient overvoltage (VFTO) after switching action. The VFTO will generate transient electromagnetic fields and cause interferences to the secondary side cables. In recent years, the anti-interference

Power distribution in remote areas with low density load is usually performed with Single Wire Earth Return (SWER) systems. These systems have been shown to be insufficient to meet not only the growing demand but also three-phase loads. The Three-Phase-Two-Wire (TPTW) system is a non-conventional low-cost alternative system for repowering the SWER, as both of them use the ground as conductor. The TPTW

This paper presents an analysis of the value that can be realized by medium-voltage back-to-back (MVB2B) converters in terms of the increased utilization rate of distributed energy resources (DERs) and the improvement in operational conditions. A systematic, transferrable, and scalable methodology has been designed to analyze and quantify the increased DER value from three perspectives: 1) curtailment

Many elder tunnels often lack waterproofing facilities, and water can easily accumulate in tunnel bottom or even on cable surface. Using the finite element method (FEM), the three-dimensional tunnel cable model, which couples the fluid field, the heat transfer and the moisture transport, is developed in our study. The coupling effects especially the phase change behavior are comprehensively considered

Distribution of network repair scheduling after disasters (DNRSD) is important for developing a reasonable repair strategy and improving the efficiency of distribution of network repair after disasters. This study considers two cooperative relationships in the repair model, namely, simultaneous cooperation (SC) and ordered cooperation (OC), and proposes a new post-disaster distribution network repair

A restricted earth fault (REF) protection element provides sensitive detection of ground faults near the neutral of a transformer or a generator. The sensitivity gains from the REF element are especially more valuable when the equipment is low-impedance grounded when the transformer phase differential element (87T) is ineffective. However, the REF element faces several challenges in low-impedance grounded

In recent years, harmonic current levels have increased in residential distribution networks due to the growing penetration of nonlinear loads at customer premises. To properly model the harmonic current injection of residences, probabilistic models that account for the stochastic behavior of domestic loads are needed. As a part of the study reported in this paper, a field measurement campaign was

Condition monitoring of generators is one of the main keys to reduce outages and keep the system stable during disturbances. The partial discharge (PD) test is among the most reliable tools for diagnosing generator insulation defects in the early stages. However, various studies show that it is impossible to correlate the measurement results with the apparent charge of the occurred PD in the generator

The scheme of configuring the Petersen coil after actively measuring the capacitive current of a network has been largely adopted, but the feedback of the compensation state is not usually used. This paper proposes a new method of adjusting the Petersen coil by using the information obtained after arc extinction. Using the equivalent circuit of a single-phase grounding fault in the resonant grounding

Monitoring, operation, and protection of distribution power grids fundamentally rely on the accurate estimation of line impedances. However, line impedance estimation is challenging due to the difficulties in modeling the dependence on line temperature and aging. This paper proposes a new data-driven strategy to estimate low-voltage (LV) and medium-voltage (MV) line impedances using an advanced metering

High-impedance faults are a challenging problem in power distribution systems. They often do not trigger protection devices and can result in serious hazards such as igniting fires when in contact with vegetation. The current research field dedicated to studying these faults is extensive but suffers from a constraining bottleneck of a lack of real experimental data. Many works set to detect and localize

The voltage-current characteristic of metal-oxide varistors is experimentally investigated for a wide frequency range. Concave exponential and rectangular impulse currents that resemble lightning current field records are employed to investigate their energy coordination with transient voltage suppression diodes, commonly integrated into printed circuit boards to protect sensitive electronic components

This paper proposes a novel framework for modular multilevel converter (MMC) current harmonic emission estimation from medium voltage (MV) charging stations. The framework is enlightened by wave decomposition, exploiting an analytical derivation of the emission, without a time-domain model. Accordingly, voltage harmonic distribution in grids can be estimated with a frequency-domain model, using the

When concerning the installation and operation costs, it is always desirable to protect an overhead distribution network with a limited quantity of surge arresters (SAs). This paper presents a novel procedure for designing differentiated protection against lightning, by identifying appropriate positions for those SAs on the overhead line. Rather than the traditional flashover rate of a whole line,

Fault detection is one of the most important research topics till today in the field of VSC-HVDC grids protection. In this subject, fast and reliable identification of faults is the most demanding issue, which still requires further study. In this respect, this paper proposes an index for fault detection, which is based on correlation between the powers of DC-link capacitor and the protected line.

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The paper “Complete Provision of MPC-Based LFC By Electric Vehicles With Inertial and Droop Support from DFIG-Based Wind Farm,” [1] contains two errors which are detailed as follows:

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Infrared camera can be used to monitor the condition of substation electrical equipment. Fast and accurate target detection algorithm is the key for infrared intelligent on-line routing inspection. However, the performance of traditional detection algorithm is poor due to the complex background of substation. To solve this problem, this paper proposes a target detection model based on the improved

This paper presents systematic research of a grounding down-lead design and its optimization for a novel Y-shaped composite pylon. A grounding down-lead inside the cross-arm is proposed as a potential grounding method. The transient response to lightning surges is modeled in PSCAD/EMTDC for a flash of lightning striking at the tip of the pylon. Aiming at the characteristic of the pylon structure, we

Accurate tower models for fast transients are essential for the insulation design of overhead lines, since lightning may produce temporary or even permanent faults. The aim of the work is to further investigate the nature of the electromagnetic modes supported by the tower, and on the applicability of the transmission line approaches, originally inspired by the model proposed by Jordan. The influence

The commutation failure immunity index (CFII) recommended by CIGRE is an useful indicator for quantifying the immunity of LCC-HVDC inverters to the CF. It should be calculated by the electromagnetic transient (EMT) simulations under the worst fault condition that doesn't cause the CF as per its definition. Moreover, the symmetrical three-phase line-to-ground fault has been empirically claimed by CIGRE

The applicability of existing single aging indicator-based lifespan prediction methods needs further improvement during different aging stages. Considering the aforementioned challenges, this work proposes a two-stage residual lifespan prediction model based on both methanol and furfural. Firstly, the changes in methanol and furfural contents in oil are examined concurrently with the aging duration

The data-driven models have achieved remarkable advancements in diagnosing gas-insulated substation (GIS) insulation defects on specific massive datasets. However, restricted by field operating conditions and sample scarcity of GIS, the above methods are difficult to achieve high-precision and robust diagnosis of GIS insulation defects on-site. To settle these problems, we propose an innovative domain

This paper presents a control system of an active power filter (APF) based on vibrating reference frame transformation. The proposed vibrating reference frame provides a representation of non-sinusoidal quantities (here the active filter current vector) in the form of sinusoidal signals in a stationary frame, and thanks to that, DC signals are achieved in a dq synchronously rotating frame. The article