Combined digital measuring current and voltage transformers (DCVTs), developed at Ivanovo State Power engineering University (ISPEU), are innovative products. The researchers have accumulated some operating experience...
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The study investigated the influence of electromagnetic absorber (EA) thickness on the time and frequency characteristics of a two-conductor microstrip transmission line (TL). The structure with EA applied as a coatin...
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In this article, we investigate the problem of fast finite-time target tracking control of the inertially stabilized platform (ISP) with a camera that mounted on a mobile robot. At first, the kinematics of the onboard...
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One of the primary challenges for Unmanned Aerial Vehicle (UAV) developers is to improve their endurance while in the air, as their typical flight time is limited to a few hours. One widely used technology to enhance ...
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Electromagnetic current transformers, invented more than 100 years ago, are today the most widespread type of preliminary current converters, used in organizing metrological channels for commercial and technical elect...
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ISBN:
(纸本)9798331501105
Electromagnetic current transformers, invented more than 100 years ago, are today the most widespread type of preliminary current converters, used in organizing metrological channels for commercial and technical electricity metering, measuring and relay protection systems. Despite their relatively simple design and modest price, today the question of using unconventional preliminary current converters (Rogowski coils, optical transformers, galvanic-magnetic sensors) is being increasingly raised [1]. This situation is due to the shortcomings of electromagnetic current transformers (CT): large weight and dimensions), explosion and fire hazard, and also saturation of their magnetic conductor in transient modes with the presence of an aperiodic component in short circuiting (SC) current. The phenomenon of saturation leads to significant distortion of the transmitted secondary signal, which in turn may become the cause of overprotection with external SC or delayed protection with internal SC. Russian and international practice in coordinating CT characteristics and relay protection requirements presuppose ensuring correct operation of relay protection systems not only in steady, but also in transient modes with possible saturation of CT magnetic conductors [2]-[5]. At present, testing the correct operation of relay protection and automation devices (RPAD) in transient modes is carried out using the CT saturation time, which under the specific conditions of the location of the CT should be more than the exact current conversion time required for correct operation of the connected RPAD. This time is calculated by special approved methods [2]. Such use of two extreme CT magnetic conductor conditions (saturated/unsaturated), without regard to the current waveform itself may lead to significant inaccuracies in evaluating the correctness of RPAD operation. Fig 1 shows two instances of saturation in one and the same CT in different operating conditions and with the same time be
One of the most important goals of theoretical ecologists is to find a strategy for controlling the chaos in ecological models to maintain healthy ecosystems. We investigate the influence of fear and the supply of add...
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The paper deals with the design and implementation of safety functions for a CNC milling machine. It is a relatively small CNC milling machine that does not pose a great danger to trained persons. Because it is used i...
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controlling an active distribution network(ADN)from a single PCC has been advantageous for improving the performance of coordinated Intermittent RESs(IRESs).Recent studies have proposed a constant PQ regulation approa...
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controlling an active distribution network(ADN)from a single PCC has been advantageous for improving the performance of coordinated Intermittent RESs(IRESs).Recent studies have proposed a constant PQ regulation approach at the PCC of ADNs using coordination of non-MPPT based ***,due to the intermittent nature of DGs coupled with PCC through uni-directional broadcast communication,the PCC becomes vulnerable to transient *** address this challenge,this study first presents a detailed mathematical model of an ADN from the perspective of PCC regulation to realize rigidness of PCC against ***,an H_(∞)controller is formulated and employed to achieve optimal performance against disturbances,consequently,ensuring the least oscillations during transients at ***,an eigenvalue analysis is presented to analyze convergence speed limitations of the newly derived system ***,simulation results show the proposed method offers superior performance as compared to the state-of-the-art methods.
In the development of secondary systems of stations and substations, including relay protection, automation, control, electric power metering and other features, there have recently been qualitative changes related to...
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The interaction effects among individual loops and multiple time delays are the prime reasons for degrading the closed-loop performance of multivariable systems. For highly interacting systems, decouplers are used to ...
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