An anti-power theft method for secondary circuit of energy meter current transformer
At present, power theft ways become increasingly subtle and intelligent. Power theft not only has caused a great loss to the nation and the power sector, but also has brought serious security risks to the equipment and personal health. Although the power theft behavior of the energy meter voltage transformer secondary circuit has been well recognized and effectively suppressed, the anti power theft method for the secondary circuit of the energy meter current transformer is still a weak link. Therefore, this paper proposes a transient method based anti power theft method for the secondary circuit of the energy meter current transformer. This method applied the pulse signal to the secondary circuit of the energy meter current transformer first, then obtained the equivalent resistance and inductance parameter of the circuit by measuring the transient value of the circuit response current. Comparing these parameters with the original parameters of the circuit, we can judge the circuit state and power theft way. The simulation results verify the accuracy and reliability of the proposed method, which is a new anti power theft method of the energy meter.
Research on Measuring Equipment of Single-Phase Electricity-Stealing with Long-Distance Monitoring Function
The power distribution monitor is an important research in electric power system, and electricity-stealing defense is one of the chief steps in distribution network reconstruction. Due to the kind of electricity-stealing and actual demand of defending stealing electricity, based on a digital single-phase electric energy meter, the metering equipment of electricity-stealing with long-distance monitoring function is designed, which adopts a low power consumption MSP430 singlechip as the control core, uses the standard electricity measure module as the basis of accurate measure of the electricity-stealing quantity, takes use of the output impulse of standard electricity measure module and user electric energy meter to calculate and judge whether happen electricity-stealing, transmits the current time and the number of electricity-stealing to the remote terminal facility through GSM network. The system also realizes the user's measuring pocket monitoring, the image acquisition about the illegal on-off state of the user's measuring pocket by using the CMOS image sensor, provides positive proof to handle lawbreakers with the behavior of electricity-stealing. Results of the user application show that the system not only realizes monitoring the behavior of electricity-stealing, accurately recording the time of electricity-stealing occur and finish, the quantity of electricity-stealing and image information of on-spot electricity-stealing, but also realizes long-distance monitor the behavior of electricity-stealing, which is convenient for centralized management .In addition, the system offers a solving method to the data of meter reading. Keywords-electricity-stealing; long-distance monitoring; single -phase; digital electric energy meter
Characterization of ceramic composite membrane filters for hot gas cleaning
Abstract Novel composite ceramic membrane filters suitable for hot gas cleaning operations have been prepared from fly ash and titania particles on stainless steel woven mesh substrates. Both membranes had a structure like a solid packed bed with a thickness of less than 100 μm. In the domain of laminar flow, significant differences in the pressure drop between experimental results and those predicted from the Kozeny-Carman relationship were found, particularly for flow through the titania membrane. Membrane filters with extremely small pores such as the titania membrane are greatly affected by slip up to 80% in permeability at elevated temperatures. Efficiencies of filtration of typical coal fired power station exhaust fly ashes were found to be greater than 909% for both titania and ash membranes, whilst there was greater variation in the pressure drops in the ash membrane than in the titania at typical gas flows.