132 results about "Flow computation" patented technology

A pressure and flow calculation technique can be used in a distributed process network simulation system that uses the sequential solving method to perform better or faster simulations of a process flow, especially with respect to process junction nodes at which flow either converges or diverges. The pressure and flow variable determination technique uses a grouped node identification technique that identifies a local set of nodes for each junction node of the process network to use when solving for the pressure at the junction node, a grouped node iteration technique that uses the grouped set of nodes at each junction node to perform iterative pressure calculations at the junction node, and a flow-based pressure calibration technique at each junction node to enable the system to perform highly accurate pressure and flow variable determination at each junction node in real-time.

The invention belongs to the field of maintenance scheduling evaluation and optimization in the power system and relates to a maintenance scheduling safety evaluation method based on power generation loss and load supply adequacy. The method comprises the following steps: firstly integrating network topology data and planning data into flow data, extracting the missing data from the reference flow data to form complete flow, simultaneously carrying out sensitivity analysis based on network topology and computing the generating capacity loss and the load supply adequacy according to the results of sensitivity analysis and flow computation, wherein evaluation based on the generating capacity loss is to compute the sensitivity of a generator to all the branches by system network topology and compute the normalized value of the generating capacity loss according to the formula; and evaluation based on the load supply adequacy is to compute the adequacy of bus load supply according to the flow computation result, the sensitivity computation result and the branch operating limit restraint. The method solves the problems in the existing methods.

A shock absorption device and a control method thereof for a small swing radius (SSR) excavator are provided, which can relieve shock generated on a boom cylinder by controlling only the discharge flow rate of hydraulic pumps, being supplied to the boom cylinder, even without controlling a main control valve when a boom of the excavator ascends at its maximum height through manipulation of a control level. The shock absorption device for an SSR excavator includes first and second hydraulic pumps, a control lever, a boom cylinder coupled to the first hydraulic pump, a main control valve for controlling a start, a stop, and a direction change of the boom cylinder, a boom-up manipulation amount detection means, a hydraulic pump flow computation means, a boom confluence means for making hydraulic fluid discharged from the first and second hydraulic pumps confluent together, a boom deceleration region detection means for detecting a boom deceleration region, and a flow controller for controlling the discharge flow rate of the first and second hydraulic pumps.

The invention provides a flexible high-voltage direct-current (HVDC) load flow computational model and a computational method thereof. The model is arranged in an alternative-current / direct-current composite electric network and comprises a control system, a converter transformer 1, a converter transformer 2, a filter 1, a filter 2, a commutation reactor 1, a commutation reactor 2, a virtualization service client (VSC) current converter 1, a VSC current converter 2, a direct-current capacitor and a direct-current power transmission circuit as well as an alternative-current electric network 1 and an alternative-current electric network 2, which are accessed by a direct-current system; and the method comprises steps of (1) increasing parameters of the converter transformer and a filter in the data of the alternative-current electric network; (2) inputting flexible HVDC systematic parameters and performing per-unit processing for the systematic parameters; (3) calculating VSC equivalent power generation active power controlled by constant direct-current voltage; (4) setting a type and a running parameter for a VSC equivalent power generator; and (5) starting the alternative-current / direct-current composite load flow computation. Due to the adoption of the model and the method, the flexible HVDC alternative-current / direct-current composite electric network load flow computation can be realized, the development and maintenance of a great amount of codes are not needed, the load flow status of the composite electric network can be high-efficiently solved, and an initial value can be provided for the dynamic property simulation of the composite electric network.

The invention discloses a valve flow function optimization method based on unit operation data. According to the method, operation data of a thermal power generating unit is processed to obtain actual valve flow performance data of the thermal power generating unit; finally, an ideal valve flow function is established on basis of the actual valve flow performance data; configuration of a digital electro-hydraulic system of the thermal power generating unit is set with the ideal valve flow function so that an actual valve flow function is consistent to the ideal valve flow function, and the valve flow function is optimized. Compared with the prior art, the method has the advantages that the valve flow function can be optimized without performing a valve flow performance test, optimization time is shortened, and optimization efficiency is improved; the influence of main steam pressure is fully considered in the calculation of theoretical steam flow, a calculation error caused by fluctuation of the main steam pressure is avoided, and optimization precision is improved.