Suppression of the high-frequency disturbances in low-voltage circuits caused by disconnector operation in high-voltage open-air substations

1986 ◽  
Vol 133 (5) ◽  
pp. 293 ◽  
Author(s):  
M.S. Savic
Keyword(s):  
High Voltage ◽  
High Frequency ◽  
Low Voltage ◽  
Low Voltage Circuits

scholarly journals Adapter-Transceiver for HF Equipment PLC Technology

2020 ◽  
Vol 20 (3) ◽  
pp. 97-109
Keyword(s):  
High Voltage ◽  
Power Supply ◽  
Low Voltage ◽  
Radio Channel ◽  
Power Line ◽  
Ferrite Core ◽  
Information Signal ◽  
Fire Alarm System ◽  
Low Voltage Circuits ◽  
Easy Integration

The paper analyses the features of PLC technologies and describes the circuitry solutions for HF equipment adapters used and their operation modes. It also proposes a new type of transceiver adapters based on a new construction principle that implements a magnetoelectric effect in the structure of a composite. One of the main components of the proposed adapters, which actually translates the HF information signal into the phase wires of the power line, is a ferrite core. The physical effects underlying the operation of the proposed transceiver adapter are analyzed. The main distinguishing feature of the proposed adapter is the absence of transformer and galvanic connections between the high-voltage power line of the power supply network and low-voltage information circuits, which ensures that the effect of the operational high voltage of the power supply line on the low-voltage circuits of HF equipment is blocked. This allows for an easy integration of the proposed version of the adapter-transceiver into standard HF equipment for PLC technologies, boosting the level of its function. The developed new types of adapter-transmitter and adapter-receiver were experimentally tested as part of an experimental fire alarm system, which uses two types of transmission channels: based on wireless technologies employing a radio channel and a PLC technologies-based one.

scholarly journals Behavior of Residual Current Devices at Frequencies up to 50 kHz

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1785
Author(s):  
Stanislaw Czapp ◽  
Hanan Tariq
Keyword(s):  
Electric Shock ◽  
High Frequency ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Residual Current ◽  
Indirect Contact ◽  
Additional Protection ◽  
Operating Current ◽  
Low Voltage Circuits ◽  
Frequency Components

The use of residual current devices (RCDs) is obligatory in many types of low-voltage circuits. They are devices that ensure protection against electric shock in the case of indirect contact and may ensure additional protection in the case of direct contact. For the latter purpose of protection, only RCDs of a rated residual operating current not exceeding 30 mA are suitable. Unfortunately, modem current-using equipment supplied via electronic converters with a pulse width modulation produces earth fault currents composed of high-frequency components. Frequency of these components may have even several dozen kHz. Such components negatively influence the RCDs’ tripping level and, hence, protection against electric shock may be ineffective. This paper presents the results of the RCDs’ tripping test for frequencies up to 50 kHz. The results of the test have shown that many RCDs offered on the market are not able to trip for such frequencies. Such behavior was also noted for F-type and B-type RCDs which are recommended for the circuits of high-frequency components. Results of the test have been related to the requirements of the standards concerning RCDs operation. The conclusion is that these requirements are not sufficient nowadays and should be modified. Proposals for their modification are presented.

Study on Sine-Wave Driving Circuits for EMCCD and its Electron Multiplication Gain

2011 ◽  
Vol 317-319 ◽  
pp. 1062-1067 ◽  
Author(s):  
Yu Gui Zhang ◽  
Tao Li ◽  
Zhi Kuan He ◽  
Zhi Xue Han
Keyword(s):  
High Voltage ◽  
High Frequency ◽  
Low Voltage ◽  
Light Level ◽  
Sine Wave ◽  
Low Light ◽  
Analog Device ◽  
Multiplication Gain ◽  
Electron Multiplication ◽  
The Relationship

A sine wave with high frequency and high voltage is a key driving signal for EMCCD to realize electron multiplication. According to signal requirements, DDS technique based on FPGA is employed and then sine-formed code-stream is converted to low-voltage sine wave by a digital/analog device. Afterwards, filtering and high-voltage amplification are used to acquire the sine wave with high frequency and high voltage. For the high-voltage amplification, the transfer function of the circuit system is used to correct the circuit parameters, and at last linear amplified sine wave signal with the functions of phase adjusting and amplitude controlling is obtained. By using the sine-wave to drive the EMCCD, low light level imaging is well acquired by the camera and the relationship between sine-wave amplitude and multiplication gain is tested.

Respiratory and blood pressure responses to stimulation of peripheral afferent nerves

1965 ◽  
Vol 208 (5) ◽  
pp. 993-999 ◽  
Author(s):  
S. Katz ◽  
J. H. Perryman
Keyword(s):  
Blood Pressure ◽  
Peripheral Nerve ◽  
High Voltage ◽  
High Frequency ◽  
Low Voltage ◽  
Low Frequency ◽  
Minute Volume ◽  
High Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Of

Experiments on cats anesthetized with pentobarbital sodium indicate that a change in the frequency of peripheral nerve stimulation will alter the direction of the blood pressure and respiratory response only after a certain intensity of stimulation is attained. Low voltage-high frequency (1–3 v, 60/sec), high voltage-low frequency (15 v, 10/sec) and low voltage-low frequency stimulation of the tibial and/or peroneal nerves initially produces a decrease in blood pressure (20–50 mm Hg) and a decrease in respiratory minute volume (13–92%). However, high voltage-high frequency stimulation generally produces an increase in blood pressure of 10–65 mm Hg and an 8–14% increase in minute volume. In decerebrate cats, low-voltage, high-frequency as well as high-voltage, high-frequency stimulation of the tibial nerve results in an increase in blood pressure, minute volume, and/or rate and amplitude of phrenic nerve discharge. Frequency and intensity are therefore interrelated. Anatomical specificity of limb peripheral nerve fibers into pressor and depressor afferents is not substantiated.

Low-Voltage Variable Gain Current Amplifier for High-Voltage Signal Processing

2009 ◽  
Vol 129 (8) ◽  
pp. 1511-1517
Author(s):  
Nicodimus Retdian ◽  
Jieting Zhang ◽  
Takahide Sato ◽  
Shigetaka Takagi
Keyword(s):  
Signal Processing ◽  
High Voltage ◽  
Low Voltage ◽  
Current Amplifier ◽  
Variable Gain ◽  
Voltage Signal

Analysis and Design of 3.3 kV IGBT Based Three-Level DC/DC Converter with High-Frequency Isolation and Current Doubler Rectifier

2009 ◽  
Vol 25 (25) ◽  
pp. 103-108
Author(s):  
Dmitri Vinnikov ◽  
Tanel Jalakas ◽  
Indrek Roasto
Keyword(s):  
High Voltage ◽  
High Frequency ◽  
Power Converter ◽  
Rolling Stock ◽  
Analysis And Design ◽  
Auxiliary Power ◽  
Igbt Modules ◽  
Isolation Transformer ◽  
New Generation ◽  
Generation Power

Analysis and Design of 3.3 kV IGBT Based Three-Level DC/DC Converter with High-Frequency Isolation and Current Doubler RectifierThe paper presents the findings of a R&D project connected to the development of auxiliary power supply (APS) for the high-voltage DC-fed rolling stock applications. The aim was to design a new-generation power converter utilizing high-voltage IGBT modules, which can outpace the predecessors in terms of power density, i.e. to provide more power for smaller volumetric space. The topology proposed is 3.3 kV IGBT-based three-level neutral point clamped (NPC) half-bridge with high-frequency isolation transformer and current doubler rectifier that fulfils all the targets imposed by the designers. Despite an increased component count the proposed converter is very simple in design and operation. The paper provides an overview of the design with several recommendations and guidelines. Moreover, the simulation and experimental results are discussed and the performance evaluation of the proposed converter is presented.

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