Equivalent Model of Photovoltaic Power Station Considering Different Generation Units’ Fault Current Contributions

The fault current calculation model of photovoltaic (PV) power stations is usually treated as a capacity weighted equivalent model of a single PV generation unit (PVGU). However, in the same PV power station, different PVGUs have various fault current characteristics. As a result, there are significant differences in fault current characteristics between a PVGU and a PV power station. It means that the existing capacity weighted equivalent model cannot be used for accurately describing the fault current contributions from a practical PV power station. In this paper, the fault behaviors of the PVGUs located at different access points of a PV power station are firstly analyzed. The difference in PVGUs’ fault current contributions is identified and reflected with the activation states of current limiters that are employed for PV inverters. The activation states are represented by a theoretical expression so as to distinguish the PVGUs’ fault contributions. Further, based on the proposed theoretical expression, a novel algorithm is developed for sorting all PVGUs included in a PV power station. The multi-machine calculation model is deduced in order to exactly express the fault current contribution from a PV station. Finally, some simulation tests are conducted. The tested results verify the effectiveness of the proposed calculation model. It can provide support for calculating the protection setting of power grid connected with large-scale PV stations.

Method of power consumption calculation of air conditioning systems on the basis of probability-statistic climate model

The article discusses the methodology for calculating the annual, seasonal and monthly consumption of heat, cold, electricity and water for air conditioning systems based on the temperatures and enthalpies of outdoor air averaged for each weather zone during the working day according to a probabilistic-statistical climate model. The article contains a brief description of the engineering methodology for quick manual calculation of resource consumption with a comparison of the results when using simplified tables of climatic information about weather zones of various external air purification in devices of the central air conditioning system. An example of calculating the annual costs for a system controlled by the "optimal modes" method according to the direct flow scheme with a bypass of the humidification chamber and the controlled process in the air cooler is studied. The advantages of the proposed engineering method lie not only in accuracy, but also in that it allows you to consider the operation of the installation during the year with greater detail for each air purifier. It is shown that the simplified procedure is suitable for use, since it gives discrepancies with machine calculation, which is no more than 10%, which is acceptable for engineering practice.

Pembuatan Dan Pengujian Mesin Penumbuk Daging Rendang Suir Kapasitas 1kg/Jam

Rendang is a typical food from Minangkabau that must be present in every custom event in Minangkabau, to improve the quality of the rendang meat, processed rendang meat is processed into processed rendang suir meat to improve the quality of its resistance. At this time the process of making rendang meat still uses a manual process which certainly does not fulfill all the desires of consumers, so the meat rending machine is made with a capacity of 1 kg / minute. This machine functions to pound rendang meat so that fiber from meat looks easier to stir. This machine aims to help the process of pulverizing the rendang meat to become flush. In this machine. The drive system is a fixed clutch, which is connected to one another. Making this frame using ST 37 iron whose dimensions are 350 mm x 550 mm x 700 mm. Whereas for the dimensions of pounding rendang suir meat is 10 mm x 200 mm x 350 mm. How it works rendang meat is placed on the bottom pounder. Then press the male clutch pedal so that there is friction between the male and female coupling so that the pulverization process occurs. After the collision results reach the desired release, step on the clutch pedal, then take the mashed meat. The making of rendang suir meat pounder machine begins with identification and field survey of whatever demands for the needs of producers of rendang suir meat. Then the next stage is the determination of several alternative planning, then the determination of the concept of planning, machine calculation, drawing the planning model.

Platform Policing and the Real-Time Cop

Policing, particularly in the United States, is being progressively datafied. This process has a historical trajectory that is crucial to the analysis and critique of new platform-based security architectures. Predictive policing has already attracted considerable attention, partially due to its seemingly novel fusion of predictive analytics and police work. Hyperbolic early claims—often mobilizing science fiction imagery—that the future could, in fact, be predicted, pointed towards utopic/dystopic imaginaries of seamlessly integrated control. Predictive policing is, however, increasingly only one component of cloud-based data systems that are coursing through police activity. The imaginary of these transformations can be analysed through the security imaginary of policing as a process of real-time data transmission, perpetually self-adjusting and self-augmenting through machine calculation. The historical contextualization of this imaginary suggests useful vectors of inquiry that position platform policing squarely within the mechanisms of contemporary capitalism.

Systems of Imprimitivity for the Clifford group

It is known that if the dimension is a perfect square the Clifford group can be represented by monomial matrices. Another way of expressing this result is to say that when the dimension is a perfect square the standard representation of the Clifford group has a system of imprimitivity consisting of one dimensional subspaces. We generalize this result to the case of an arbitrary dimension. Let k be the square-free part of the dimension. Then we show that the standard representation of the Clifford group has a system of imprimitivity consisting of $k$-dimensional subspaces. To illustrate the use of this result we apply it to the calculation of SIC-POVMs (symmetric informationally complete positive operator valued measures), constructing exact solutions in dimensions 8 (hand-calculation) as well as 12 and 28 (machine-calculation).

Optimization Method of Man-Machine Operating for Multi-Variety and Small Batch Production

According to the characteristics of the multi-variety and small batch production units, the traditional man-machine operating analysis methods can not meet the needs of the optimized manufacturing process. In order to maximize the utilization of man-machine resource, a man-machine combination and mixed flow processing method is proposed in this paper. It involved several integrated application methods. The man-machine operating analysis method can optimized the process of the man-machine operating, and also can acquired the important parameters of the man-machine operating in each species production processing, The integration of gather form, histogram and single people-multi-machine calculation formula made the various products processing parameters analysis and the remaining energy utilization easily. By using this method, the optimized plan of the man-machine combined in various products processing can be determined. The characteristics of the proposed method are that it extends the design program of man-machine combination and mixed flow processing. The test results show that the new method works well in the multi-variety and small batch production model.