摘要:
A feedforward voltage series compensator based on complimentary use of wind, solar, and electric power comprising a controller, a rectifier unit, an H bridge inverter, a series transformer, a wind-power DC voltage sensor, a wind-power DC current sensor, an AC voltage transducer, a DC boost unit, a PV DC voltage sensor, a PV DC current sensor, and a grid-connected inverter. The compensator makes use of wind-electric and photovoltaic-electric complimentary interactions to solve the traditional energy issue for series compensator, and as the grid-connected inverter is feedforward, there is extra capacity for the series transformer and the series complimentary inverter unit, and hence it enjoys the feedforward and quick voltage complimentary characteristics of the wind and solar power generation.
摘要:
A method for designing cascaded multi-level inverters with minimization of large-scale voltage distortion, based on KKT (Karush-Kuhn-Tucker) conditions and with simplified computation of conduction angles, simplifies the computation process, and is conducive to on-line calculation. Meanwhile, its fundamental voltage is adaptive, minimization of total harmonic is realized for cascaded multi-level inverters at high-voltage, and voltage power quality at grid connected nodes is improved.
摘要:
A method for detecting and locating faulty line on the distribution network circuit based on full waveform information, which uses the current data on the fault occurrence and whole-process operation of the compensation device to effectively solve such common problems as low fault current, poor reliability and low sensitivity in case of single-phase grounding fault to the low-current system through precise GPS synchronization. It improves the sensitivity and reliability of the grounding fault detection, which does not interfere with the system and is applicable to high-resistance grounding.
摘要:
Power distribution network early failure detection method comprising: a waveform is decomposed into an approximation part and detail parts by wavelet transform, wherein the approximation part is referred to as an approximate shape primitive, and the detail parts are referred to as distortion primitives; the distortion primitives are divided into three primitives including harmonics, pulses and other distortions based on extreme points; characteristics of the primitives and time relationships between the primitives are extracted; probability distribution of the waveform is constructed according to the characteristics of the primitives and the time relationships between the primitives; and a judgment result of the waveform is obtained according to probability distribution of waveforms of different types.
摘要:
A maximum power output circuit for EHC and its design method are presented. The circuit is comprised of a magnetic core, that is, a primary coil and a secondary coil, with a load resistor and a capacitor parallel connected at the two ends of the secondary coil. The circuit enables the EHC to be always working at the maximum power output, s thus realizing maximum power output of the energy harvesting power source.
摘要:
A parallel connection method and a device for multi-channel partial discharge (PD) signals have input sources of pre-processed and amplified signals received by multiple PD sensors. Then isolation and processing are provided to the signals to ensure that each signal is able to be self-triggered and unidirectional transmitted. Finally, processed signals of each channel are outputted. For ultra-high frequency (UHF) PD signal, the delay transmission is realized by a surface acoustic wave (SAW) delay line method. The present invention makes the amplified multi-channel PD signals self-trigger and unidirectional transmit though isolation processing and then realizes parallel connection without interference. The method also decreases signal transmission loss. Meanwhile, all the detected PD signals transmit on one signal bus through parallel connection method, so as to use only one set of acquisition unit to monitor and acquire the signals received by multiple sensors, which obviously lowers the system cost.
摘要:
A maximum power output circuit for EHC and its design method are presented. The circuit is comprised of a magnetic core, that is, a primary coil and a secondary coil, with a load resistor and a capacitor parallel connected at the two ends of the secondary coil. The circuit enables the EHC to be always working at the maximum power output, thus realizing maximum power output of the energy harvesting power source.
摘要:
A method for identifying a lightning fault of an overhead transmission line (OTL) comprising determining a polarity of a travelling wave of each of three ABC phases subsequent to a single phase outage of the OTL. If the polarity of each phase is the same, the outage is a lightning fault and its type a back flashover; if not the same, proceed to the second step to determine a current change rate R of the fault phase. If R is larger than a threshold value, the outage is a lightning fault and its type a shielding failure; otherwise, the outage is a single-phase grounding fault. A system for identifying the lightning fault which comprises successively at least a group of fault detectors, a wireless communication module, a remote monitoring master station which adopts the above method to determine the fault type of the overhead transmission line.
摘要:
A parallel connection method and a device for multi-channel partial discharge (PD) signals have input sources of pre-processed and amplified signals received by multiple PD sensors. Then isolation and processing are provided to the signals to ensure that each signal is able to be self-triggered and unidirectional transmitted. Finally, processed signals of each channel are outputted. For ultra-high frequency (UHF) PD signal, the delay transmission is realized by a surface acoustic wave (SAW) delay line method. The present invention makes the amplified multi-channel PD signals self-trigger and unidirectional transmit though isolation processing and then realizes parallel connection without interference. The method also decreases signal transmission loss. Meanwhile, all the detected PD signals transmit on one signal bus through parallel connection method, so as to use only one set of acquisition unit to monitor and acquire the signals received by multiple sensors, which obviously lowers the system cost.