Detection Of Voltage Disturbances Research Articles

Simple and Fast Voltage Disturbance Detection and Voltage Reference Generation Approach for Dynamic Voltage Restorer (DVR) to Compensate Unbalanced Voltage Sag and Swell in Three-Phase System: Simulation and Experimental Testing

The dynamic voltage restorer (DVR) is an important device for coping with voltage sag, swell, and unbalance. However, it is a real-time mechanism and must operate as quickly as possible to protect the sensitive and critical load from supply-side voltage anomalies. Hence, fast detection of voltage disturbances and reference voltage generation is essential for the DVR. This paper proposes a simple and fast voltage disturbance detection approach based on a simple three-phase phasor diagram which is easy to implement. The controller employed for the DVR uses a sliding mode control, making the entire system robust and insensitive to system parameter variations. Three different scenarios are simulated according to arbitrarily imposed supply conditions, verified in laboratory tests using the DSP R&D controller board. The results demonstrate a simpler, faster voltage-anomaly detection process which is easier for implementation compared to the other methods in the literature. The best and worst detection times (DTs) of the proposed approach are 1 and 4 ms, respectively. It yields a rapid response, accurate compensation, and robustness in restoring the load voltage to its nominal value within two cycles.

Quaternions-based detection of power quality events

This paper presents a new method for the detection of voltage disturbances caused by various reasons in households and industries. The aim of the paper is to improve the power quality disturbance methods and implement it in real-time with a very high accuracy and use existing mitigation techniques after classification of the signal. The method involves a novel idea to use the quaternions for the purpose of signal tracking. The envelope formed by Hilbert envelope detection method is used as an input for the quaternions. The quaternions produce a spike whenever there is a deviation from the pure sine wave giving very accurate results in a very short period of time. Combination of SVM and DSmT classifier is used for recognizing and classification of different signals such as sags, swells, transients and other power quality disturbances, hence can be used to monitor the power quality.

Voltage Regulation Using Recurrent Wavelet Fuzzy Neural Network-Based Dynamic Voltage Restorer

Dynamic voltage restorers (DVRs) are one of the effective solutions to regulate the voltage of power systems and protect sensitive loads against voltage disturbances, such as voltage sags, voltage fluctuations, et cetera. The performance of voltage compensation with DVRs relies on the robustness to the power quality disturbances and rapid detection of voltage disturbances. In this paper, the recurrent wavelet fuzzy neural network (RWFNN)-based controller for the DVR is developed. With positive-sequence voltage analysis, the reference signal for the DVR compensation can be accurately obtained. In order to enhance the response time for the DVR controller, the RWFNN is introduced due to the merits of rapid convergence and superior dynamic modeling behavior. From the experimental results with the OPAL-RT real-time simulator (OP4510, OPAL-RT Technologies Inc., Montreal, Quebec, Canada), the effectiveness of proposed controller can be verified.

A Comprehensive Overview of Digital Signal Processing Methods for Voltage Disturbance Detection and Analysis in Modern Distribution Grids with Distributed Generation

A Comprehensive Overview of Digital Signal Processing Methods for Voltage Disturbance Detection and Analysis in Modern Distribution Grids with Distributed Generation

Study of On-Line Detection of Voltage Transient Disturbance Based on DSP and Wavelet

In this paper, a set of voltage disturbance detection device based on DSP2812 was designed and a method of transient voltage disturbance detection based on DSP and Wavelet Transform was studied. The device collects electrical signal through a Hall sensor and the parallel A/D converter and regards TMS320F2812, a kind of high-performance digital signal processor (DSP), as a core data processing unit. Discrete Wavelet Transform (DWT) algorithm on DSP board was carried out to detect transient voltage disturbance. Software modules including the main program module, A/D module, interrupt module, communication module and so on was designed. The DWT algorithm on DSP board which could detect transient voltage disturbance on line was carried out based on the strong operation ability of DSP and the high effectiveness of DWT algorithm. This device can simultaneously realize power acquisition and voltage disturbance analysis in real-time. Contrast tests show that the device is of high-precision, of high-data-processing-speed and has a capability of voltage disturbance detecting in real-time.

Voltage disturbance detection method for HTS tape using electromagnetically coupled coils

This paper represents the detection method of voltage disturbance for high temperature superconducting (HTS) tape using electromagnetically coupled coils. In order to detect the voltage as the superconductor transits from the superconducting state to the normal conduction state, voltage taps are widely used to get the voltage signal. And voltage taps are connected to data acquisition device via signal wires. However this new suggested method can detect the superconducting transition voltage without signal wires between voltage taps and data acquisition device by using electromagnetically coupled coils. This system consists of two electromagnetically coupled coils, the first coil to detect and transmit the voltage of HTS tape and the second coil to pick up the transmitted voltage from the first coil. By using this new suggested method, we can build the `separated voltage-detection system`. HTS tape and first coil are located under liquid nitrogen vessel and the second coil is located under room temperature condition. In this paper, experiments are performed to verify the feasibility of the proposed method. As the result of the experiment, the separated voltage-detection system using electromagnetically coupled coils can successfully observe superconducting-normal transition of HTS tapes.

Research on Voltage Disturbance Detection of PV System Based on Mathematical Morphological and Backward Difference

For the output of photovoltaic generation is of the characteristics of intermittent and uncertainties because of the changes of weather, the application of mathematical morphological and backward difference in voltage disturbance detection of the PV system. In order to overcome the defects caused by using fixed structural elements in general morphological filters, a form of adaptive weighted combination filter combined morphological open and closed operation is put forward. A more effective algorithm is designed by weight adding combination of morphological operation to get better effect. Three cases of examples such as voltage liter, voltage dips and voltage interruption are simulated through Matlab. The result shows the method can quickly and accurately extract the dynamic characteristics of power quality parameters of PV system.

Support Vector Machine Based Voltage Relays for Voltage Disturbance Detection in Micro-Distribution Systems

This study proposes combining fuzzy inference system and support vector machine based voltage relays for voltage disturbance detection in micro-distribution systems (MDSs). Moreover, the coordination characteristic curves of the trigger time versus dynamic errors are proposed for under-voltage and over-voltage protection. Modified coordination characteristic curves use a critical trigger time to isolate the faults. An support vector machine (SVM) is a multi-layer decision-making model, which detects voltage disturbances, such as voltage swell, voltage sag, voltage unbalance, and faults. Computer simulations are conducted, using an IEEE 30-bus power system and micro-distribution systems, to show the effectiveness of the proposed voltage relays.

Detection of Capacitor Switching Transients and L-G Fault Transients by Implementing Wavelet Transform

Abstact: In a electrical power system, whenever the voltage goes below the desired level,there is no need to improve the voltage profile. This increasing voltage can be obtained by using capacitor bank/s, as switching ON a capacitor bank/s causes increase in voltage while switching OFF a capacitor bank/s causes decrease in voltage. But these switching action, if not specifically controlled give rise to transients which are undesirable and hazardous for the power system. This introduces a voltage disturbance detection approach [1] identifies voltage disturbance, and[2] discriminate the type of event which has resulted in the voltage disturbance, e.g. either a fault or a capacitor switching incident. Feasibility of the proposed disturbance detection approach is demonstrated based on digital time domain simulation of a distribution power system using the PSCAD software package. Finally by using wavelet transform discriminate the type of event on the basic of energy levels. The demand for educational and awareness programs are recommended in order to contribute and increase the use of online transaction in the sultanate. Keyword: Capacitor switching,, distribution system, L-G,PSCAD wavelet transform, transient analysis.

Wavelet based on-line disturbance detection for power quality applications

This paper introduces a new online voltage disturbance detection approach based on the wavelet transform. The proposed approach: (1) identifies voltage disturbances; and (2) discriminates the type of event which has resulted in the voltage disturbance, e.g. either a fault or a capacitor-switching incident. The proposed approach is: (1) significantly faster; and (2) more precise in discriminating the type of transient event than conventional voltage-based disturbance detection approaches. The feasibility of the proposed disturbance detection approach is demonstrated based on digital time-domain simulation of a power distribution system using the PSCAD/EMTDC software package.