Ningbo Regional Distribution Network Neutral Point Grounding Modes Of Study And Application

Neutral grounding method of power system is a very comprehensive technical problem. The research subject of this paper is put forward through the study of neutral grounding methods both at home and abroad. This paper studies the neutral point grounding, neutral point via small resistance grounding directly, neutral point via arc suppression coil grounding, neutral point grounding, etc. The advantages and disadvantages of different grounding method, operation characteristics and practicability, and some factors affecting the neutral point grounding way is also analyzed briefly. In this paper, on the basis of comparing various grounding method, in combination with the practical case of work, the way to choose neutral point grounding way in Ningbo area distribution network is discussed and applied.In Ningbo area, the10kV public grid distribution network neutral point uses arc suppression coil grounding approach. The working principle of arc suppression coil and classification is simply analyzed in this article. By the example of Xizhou substation in Ningbo area, bus cable capacitance is calculated and the neutral point grounding way is also chosen. The selection and calculation of coil capacity are also derived in this paper.Due to increasing power supply reliability requirement and the proportion of feeder cables which is widely used, appropriate neutral point grounding way must be applied to ensure a safe and stable operation of the enterprise. In this paper, the practical schemes of petrochemical enterprise resistance grounded system are compared and the selection of capacity of grounding transformer and grounding resistance are discussed. Solutions for neutral grounding mode of large-scale petrochemical enterprises of Ningbo area are solved. The high density load, high reliability requirement, cable line feeder, and flammable issues are also solved in this paper.