Maximum technical transmission capacity is the capacity, which is physically available for transmission of natural gas at analyzed entry or exit point. The definition of maximum technical capacity shall take into account the technical capacities of all components of the gas pipeline network involved in the transmission, the configuration and operational characteristics of the gas pipeline network as a whole and its operational boundary conditions.
Analyses of transmission capacities of the gas pipeline network among components of the gas pipeline network, in addition to transmission gas pipelines and accessories, also specifically examine the measurement-control stations and compressor stations.
The technical capacities of the measurement-control stations are defined on the basis of characteristics of used flow-pressure controllers, measuring equipment, accessories, pipelines, heat exchangers, filters, separators and installed heating power of heating devices.
Technical capacities of compressor station depend particularly on the flow-pressure characteristics of gas compressors and operational characteristics of power gas turbines. The examination of compressor stations separately considers also their available operation area and insures that compressor units operate in the area of stable operation.
Gas transport system can be mathematically described by nonlinear partial differential equations. This mathematical model allows us to predict the behaviour of gas network system under different conditions. The simulation process is automated with the help of decicated computer program and runs continuously.
For analyses of transmission capacities Plinovodi d.o.o. uses software packages Pipeline Studio (Energy Solutions) and Simone (LIWACOM). With the aid of these tools, we also carry out analyses within the framework of upgrades of the gas pipeline network, recalculations for preparation of works on gas pipelines and analyses of operational states and transients in the transmission of natural gas.
The above mentioned software packages implement the transient flow analysis, solving the system of partial differential equations. This system allows us to track spatial and temporal changes of various gas properties such as gas composition.
The model of a gas pipeline network is used also for dynamic simulation of gas pipeline network in real time with software package OLS (On-Line Modelling System), which is continually operating in the Dispatch centre connected to the data from the SCADA system. In addition to useable results of the simulation in real time, the OLS system may, based on the current state of the gas pipeline network, also predict its future behaviour depending on the forecasted load and nominated natural gas transmissions, and alarm the operators in case of detection of irregular operational states.
