scholarly journals Secured wired BPL voice transmission system

2020 ◽  
Vol 198 (4) ◽  
pp. 947-955
Author(s):  
Grzegorz Debita ◽  
Przemysław Falkowski-Gilski ◽  
Marcin Habrych ◽  
Bogdan Miedziński ◽  
Jan Wandzio ◽  
...  
Keyword(s):  
American English ◽  
Mechanical Damage ◽  
Transmission System ◽  
Operating Conditions ◽  
Ideal Solution ◽  
Voice Transmission ◽  
Critical Data ◽  
Subjective Study ◽  
Phase Conductors ◽  
Partial Damage

Designing a secured voice transmission system is not a trivial task. Wired media, thanks to their reliability and resistance to mechanical damage, seem an ideal solution. The BPL (Broadband over Power Line) cable is resistant to electricity stoppage and partial damage of phase conductors, ensuring continuity of transmission in case of an emergency. It seems an appropriate tool for delivering critical data, mostly clear and understandable voice messages. This paper describes such a system that was designed and evaluated in real-time operating conditions. It involved a two-way transmission of speech samples in American English and Polish. The efficiency of the designed solution was evaluated in the subjective study on a group of 15 people.

scholarly journals Quality Evaluation of Voice Transmission Using BPL Communication System in MV Mine Cable Network

2019 ◽  
Vol 25 (5) ◽  
pp. 43-46 ◽  
Author(s):  
Grzegorz Debita ◽  
Przemyslaw Falkowski-Gilski ◽  
Marcin Habrych ◽  
Bogdan Miedzinski ◽  
Janusz Wandzio ◽  
...  
Keyword(s):  
Communication System ◽  
Quality Evaluation ◽  
Mechanical Damage ◽  
Work Conditions ◽  
Evaluation Study ◽  
Capacitive Coupling ◽  
Power Cable ◽  
Voice Transmission ◽  
Cable Network ◽  
Phase Conductors

This article presents results of a quality evaluation study, considering voice transmission in a 6 kV medium voltage cable network using the BPL (Broadband over Power Line) communication system. The tests are carried out under real mining conditions for the selected power cable without voltage, earthed at both sides. Such a method of monitoring work conditions is of great importance, especially during a disaster. Power cables are potentially resistant to mechanical damage and, thus, ensure continuity of transmission, also, in cases of electricity stoppage and partial damage (interruption) of the phase conductors. The voice transmission quality is tested for a relatively low bitrate of 8 kbps–48 kbps using both induction and mixed induction-capacitive coupling with the power cable. Such a solution should provide both reliable and high-quality services, considering clear and understandable voice messages to people. The quality evaluation is carried out on a group of 15 people aged between 25–35 years old. The tested signal samples consist of voice messages in British English, German, and Polish. On the basis of the investigated results, respective conclusions are formulated.

Optimal Placement of FACTS Devices for Voltage Stability Improvement with Economic Consideration Using Firefly Algorithm

2019 ◽  
Vol 14 (1) ◽  
pp. 5-11
Author(s):  
S. Rajasekaran ◽  
S. Muralidharan
Keyword(s):  
Power Systems ◽  
Voltage Stability ◽  
Firefly Algorithm ◽  
Transmission System ◽  
Operating Conditions ◽  
Optimal Placement ◽  
Voltage Collapse ◽  
Facts Devices ◽  
The Cost ◽  
Bus System

Background: Increasing power demand forces the power systems to operate at their maximum operating conditions. This leads the power system into voltage instability and causes voltage collapse. To avoid this problem, FACTS devices have been used in power systems to increase system stability with much reduced economical ratings. To achieve this, the FACTS devices must be placed in exact location. This paper presents Firefly Algorithm (FA) based optimization method to locate these devices of exact rating and least cost in the transmission system. Methods: Thyristor Controlled Series Capacitor (TCSC) and Static Var Compensator (SVC) are the FACTS devices used in the proposed methodology to enhance the voltage stability of power systems. Considering two objectives of enhancing the voltage stability of the transmission system and minimizing the cost of the FACTS devices, the optimal ratings and cost were identified for the devices under consideration using Firefly algorithm as an optimization tool. Also, a model study had been done with four different cases such as normal case, line outage case, generator outage case and overloading case (140%) for IEEE 14,30,57 and 118 bus systems. Results: The optimal locations to install SVC and TCSC in IEEE 14, 30, 57 and 118 bus systems were evaluated with minimal L-indices and cost using the proposed Firefly algorithm. From the results, it could be inferred that the cost of installing TCSC in IEEE bus system is slightly higher than SVC.For showing the superiority of Firefly algorithm, the results were compared with the already published research finding where this problem was solved using Genetic algorithm and Particle Swarm Optimization. It was revealed that the proposed firefly algorithm gives better optimum solution in minimizing the L-index values for IEEE 30 Bus system. Conclusion: The optimal placement, rating and cost of installation of TCSC and SVC in standard IEEE bus systems which enhanced the voltage stability were evaluated in this work. The need of the FACTS devices was also tested during the abnormal cases such as line outage case, generator outage case and overloading case (140%) with the proposed Firefly algorithm. Outputs reveal that the recognized placement of SVC and TCSC reduces the probability of voltage collapse and cost of the devices in the transmission lines. The capability of Firefly algorithm was also ensured by comparing its results with the results of other algorithms.

scholarly journals Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2330
Author(s):  
Andrzej Grzegorz Lange ◽  
Grzegorz Redlarski
Keyword(s):  
Reactive Power ◽  
Second Harmonic ◽  
Transmission System ◽  
Operating Conditions ◽  
Arc Furnace ◽  
Steel Mill ◽  
Nonlinear Loads ◽  
Higher Harmonics ◽  
Current Harmonics ◽  
Arc Furnaces

This article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under various operating conditions, and an algorithm for selecting the parameters of a third-order C-type filter (for suppressing the second harmonic) and two second-order LC-type filters (for suppressing the third harmonic) was proposed. The filtering system was tested in an arc furnace with the highest rated power, and harmonics in the current spectrum were evaluated. The results of the measurements were used to analyze the effectiveness of the compensation system comprising two passive C-type and LC-type filters at different system configurations. C-type filters significantly influenced current harmonics. The influence of the changes in the number of arc furnace transformers on the true Root Mean Square (RMS) of the currents injected into the 110 kV transmission system and on the voltages of the 110 kV busbars was discussed.

On-line determination of nitrite in wastewater treatment by use of a biosensor

2002 ◽  
Vol 45 (4-5) ◽  
pp. 69-76 ◽  
Author(s):  
M. Nielsen ◽  
N.P. Revsbech ◽  
L.H. Larsen ◽  
A. Lynggard-Jensen
Keyword(s):  
Activated Sludge ◽  
Mechanical Damage ◽  
Operating Conditions ◽  
Bacterial Populations ◽  
Operational Lifetime ◽  
On Line ◽  
Low Levels ◽  
In The Beginning

A newly developed biosensor for nitrite having a 90% response time of about 1 min was used to monitor nitrite concentration in activated sludge exposed to oxic/anoxic cycles. The NO2− biosensor contains bacteria that reduce NO2−, but not NO3−, to N2O that is subsequently monitored by a built-in electrochemical sensor. Nitrite plus nitrate (NOx−) was simultaneously monitored by a NOx− biosensor. The maximum operational lifetime of the NO2− biosensor was 6 weeks, but much longer lifetimes can be expected as malfunctioning by the 3 sensors used for longer periods was due to either mechanical damage or ineffective internal sterilization during the construction. Insufficiently sterilized sensors became sensitive also to NO3− after some time due to development of NO3−-reducing bacterial populations within the sensor. The fraction of NO2− as compared to NO3− in the activated sludge was very dependent on prehistory, actual loading, and aeration. During balanced operation with NH4+ being exhausted during the later parts of the aerobic cycle, NO2− increased in concentration up to about 50 μM during the early part of the aeration cycle until NH4+ became limiting. At that time the NO2− concentration decreased to low levels. Under some operating conditions a peak of NO2− also appeared in the beginning of the anoxic period. NO2− and NO3− were depleted simultaneously during the anoxic period.

An Approach to Improving Performance of the dc Filter in HVDC Transmission System

2011 ◽  
Vol 48-49 ◽  
pp. 183-186 ◽  
Author(s):  
Ming Li
Keyword(s):  
South China ◽  
Transmission System ◽  
Operating Conditions ◽  
Hvdc System ◽  
Hvdc Transmission ◽  
Filter Performance

The Gui-Guang HVDC system in south china scheme with interconnections to the 500kV transmission to Guizhou and to Guangdong can exhibits, under certain operating conditions, the percussion of the dc filters impedance resonance problems. The analysis explains the dc filters impedance resonance. The influence of changing the dc filter parameters is also studied. Finally, an assessment is made for improve the dc filter performance

Synchro Phasor Measurement Based Fault Analysis of a Parallel Transmission Line

2014 ◽  
Vol 984-985 ◽  
pp. 996-1004
Author(s):  
D. Miruthula ◽  
Ramachandran Rajeswari
Keyword(s):  
Transmission Line ◽  
Transmission System ◽  
Fault Analysis ◽  
Operating Conditions ◽  
Measurement Unit ◽  
Fault Identification ◽  
Parallel Transmission ◽  
Inference System ◽  
Fault Type ◽  
Phasor Measurement

This paper presents a new method to classify transmission line shunt faults and determine the fault location using phasor data of the transmission system. Most algorithms employed for analyzing fault data require that the fault type to be classified. The older fault-type classification algorithms are inefficient because they are not effective under certain operating conditions of the power system and may not be able to accurately select the faulted transmission line if the same fault recorder monitors multiple lines. An intelligent techniques described in this paper is used to precisely detect all ten types of shunt faults that may occur in an electric power transmission system (double-circuit transmission lines) with the help of data obtained from phasor measurement unit. This method is virtually independent of the mutual coupling effect caused by the adjacent parallel circuit and insensitive to the variation of source impedance. Thousands of fault simulations by MATLAB have proved the accuracy and effectiveness of the proposed algorithm. This paper includes the analysis of fault identification techniques using Artificial Neural Network and Adaptive Neuro-Fuzzy Inference System based protection schemes. The performances of the techniques are examined for different faults on the parallel transmission line and compared with the conventional relay scheme. The results obtained shows that ANFIS based fault identification gives better performance than other techniques.

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