A Way to Evaluation the Process Immunity Time of Customers’ Sensitive Industries Processes

Abstract

The premise of voltage sag mitigation for sensitive industrial processes is to reasonably assess the economic losses caused by voltage sag. And the process immunity time is the key information in the process of economic loss assessment. Existing research usually obtains process immunity time through monitoring systems or overall testing. However, in the actual situation, due to various constraints, the traditional method of obtaining the process immunity time is inconvenient. To get PIT more conveniently, a sensitive process immunity evaluation method based on response information flow is proposed in this paper. This method regards sensitive industrial processes as a composite system. According to the function of each part of the system and the response characteristics of voltage sag, it can be divided into three modular combinations, which are delayed structure, competitive structure, and conductive structure. According to the delay time and module combination characteristics of module response to the voltage sag, the propagation path of response information flow caused by sag can be determined, and the process immunity time can be evaluated.Finally, a case study of the painting process of a car factory in southern China shows that the proposed method can be applied to the sensitive process immune time assessment.