[This article belongs to Volume - 46, Issue - 04]

Gas transmission capability curve of natural gas pipeline system

This paper proposes the concept of gas transmission capability curve of natural gas system, which expands the classic gas transmission capability (GTC) index. GTC, defined as the maximum allowable flow rate of a natural gas system, is used to describe the transmission capability limit of the system. However, we find that the complete capability limit should be described by a curve (GTC curve) instead of GTC, because GTC is just one point of the curve and many other critically secure states still exist except for GTC. Based on this finding, firstly, we define and model the GTC curve as the set consisted of all the critically secure states. Secondly, the sampling-based method is proposed to draw the GTC curve. Finally, we propose the related assessment indices of GTC curve. Two typical test systems are used to verify the existence of GTC curve and the proposed methods. In the two systems, there exist about 71% and 77% of critical states on the GTC curve whose total gas volumes are GTC respectively, while 29% and 23% of the critical states are not, their total gas volumes are smaller than GTC with different degrees and the most degree can reach 5.6% and 13.1% respectively. The GTC curve can describe the capability limit of the system completely, which will help the operators better understand the operational limit of the system as well as improve the security and reliability of planning schemes.