The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper employs impedance-model-based frequency domain analysis to detect subsynchronous resonances (SSR) in Type 3 wind farms with Thyristor Controlled Series Capacitor (TCSC). The contributions of this paper are (i) the derivation of dynamic phasor based TCSC impedance model and (ii) the application of such impedance model in Type 3 wind energy systems for SSR analysis. Impedance models for TCSC...
This paper investigates the influence of control bandwidth on the stability of loads, which are interfaced through power electronic converters and are fed from a dc power source. When tightly regulated, these loads exhibit a constant power load (CPL) behavior. It is shown here that the ideal CPL assumption, prevalent in literature, may not represent the worst case in real-life applications. If the...
A new high impedance fault (HIF) detection method using time-frequency analysis for feature extraction is proposed. A pattern classifier is trained whose feature set consists of current waveform energy and normalized joint time-frequency moments. The proposed method shows high efficacy in all the detection criteria defined in this paper. The method is verified using the real-world data, acquired from...
This paper presents the load flow modeling and steady-state capabilities of the bundle-controlled Line Impedance Modulator (LIM). This distributed FACTS device is under development for the management of power flows. In particular, the paper presents the back-to-back interconnection of two Bundle-Controlled Line (BCL) segments. The LIM configuration is very interesting from an economic and operational...
Well planned and adjusted protection devices increase the reliability of the system against fault events. The directional overcurrent relays, for example, play an important role in the protection of meshed transmission systems. They are usually employed as backup protection of distance relays. However, even as backup protection, the correct coordination can be set to speed up the fault mitigation...
The voltage surge due to fast switching insulated gate bipolar transistor (IGBT) and resonance can introduce voltage surge and distort the inverter output voltage/current waveforms. This may cause premature failure to sensitive loads and introduce harmonics in the grid voltage/current waveforms. This paper investigates the impacts of voltage surge and resonance on power electronic converter-fed grid-connected...
This work studies the modeling and control of a six-phase generator and rectifier unit in MVDC systems. The design approach for the generator's automatic voltage regulator (AVR) is developed based on the generator's linearized models. The dc terminal impedance of the generator-rectifier unit is derived based on system analysis and numerical approximation. Further, the dc terminal impedance of the...
Monitoring the long term voltage stability of the power grid is necessary to ensure its secure operation. In this paper, a voltage stability index that is linear with the power demand, called the M-index, based only on angles is proposed. The linearity of the M-index can be utilized to estimate the load margin directly. The linearity of the M-index is proved for the two-bus system and a method to...
Direct current transmission based on Voltage Source Converters (VSC-HVDC) has a number of advantages compared with traditional HVDC systems. However, VSC-HVDC systems are subjected to high short circuit currents due to faults in the DC line, which may contribute negatively to the dissemination and advances of this technology. In this context, this paper analyzes the impact of superconducting fault...
One big challenge raised by frequent topology change in today's power system is assessing the system protection security and dependability afterwards. This paper reviews the setting algorithm for the distance relays and proposes an automated setting calculation module. The calculation procedure is broken down into blocks which could be processed in parallel in order to improve the computation speed...
Interaction between fixed series compensation and doubly-fed induction generator (DFIG)-based wind farms can cause a new type of subsynchronous resonance (SSR) problem, which is also named as subsynchronous control interaction (SSCI). To explain its basic mechanism as well as to evaluate the risk, this paper proposes a small-signal impedance method, based on which, a practical series-compensated power...
A modified forward backward sweep load flow algorithm for unbalanced radial distribution systems is proposed in this paper. The proposed algorithm modifies branch current calculation approach in backward sweep by using three matrices. They are matrices A, B and C. These matrices are used in identifying downstream buses and also in calculating branch current or power flow in an easy manner. For accurate...
This paper proposes a new strategy to achieve voltage regulation in distributed power systems in the presence of solar energy sources and battery storage systems. The goal is to find the minimum size of battery storage and its corresponding location in the network based on the size and place of the integrated solar generation. The proposed method formulates the problem by employing the network impedance...
Growing penetrations of distributed PV generation in electrical distribution systems has a range of impacts including, notably, voltage rise in the network. This poses new challenges for electricity industry operation and planning. Existing planning tools are not necessarily appropriate in this changing context. This paper presents a novel tool for estimating the maximum PV generation that can be...
Integration of large numbers of distributed photovoltaic (PV) systems in electric distribution circuits often requires advanced functions (e.g. volt-VAR, frequency-Watt etc.). However, significant concerns have been raised about potential for PV inverters with such controls to interact with one another in a way that could cause grid instability. The lack of standardized inverter models makes it hard...
The inherently fluctuating nature of sea waves can be reflected to a significant extent in the power output of tidal turbines. However, these fluctuations can give rise to power quality issues such as flicker. Hence, it is important to assess the impact which tidal farms may have on their local network before such power plants are allowed to connect to the grid. This paper describes the influence...
This paper presents basic guidelines on design considerations for large utility-scale photovoltaic (PV) solar power plant (SPP) substation and collector grounding systems for safety aspects. While SPP grounding design is similar to both traditional power plants and substations, it's much larger scale allows and requires design optimization for an economical approach. This paper highlights items unique...
Microgrid protection presents challenges because of the presence of inverter interfaced resources which results in insufficient separation between fault and load currents. This paper uses the Dynamic State Estimation (DSE) based protection (EBP) method for the protection of microgrid components. The paper demonstrates that this method provides a reliable protection system as opposed to traditional...
Power Line carrier system works at a much higher frequency than the electricity fundamental frequency. Normally the working bandwidth is carefully selected to prevent interferences from communications on neighboring lines or possible antenna phenomenon due to the line topology. In this paper a relay misoperation caused by transfer trip when the line was taken out for construction is discussed and...
This paper proposes an online tracking algorithm to allocate and track the optimal charging frequency for lithium-ion (Li-ion) batteries in real time under any condition. The optimal frequency refers to the frequency of the sinusoidal component of the charging current at which the internal AC impedance of the battery cell is minimal. The AC impedance depends on the physical properties of the battery's...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.