Integrating solar generation brings about unique challenges in power system protection. Previous studies have found inverter-based resources featuring distinct fault responses compared to conventional generators. The reduction in fault current magnitude and lack of negative and zero sequence currents can fundamentally impact the way that the power system is protected. This letter studies the negative-sequence current injection from transmission-connected solar farms. Using field recorded data, this letter reveals the negative-sequence current injection behaviors of solar farms by analyzing how inverters respond to faults. In addition, the paper studies how the negative-sequence current can impact negative-sequence directional elements used in protective relays. The response of protective relays’ is evaluated by replaying field events using actual relay settings applied on conventional systems.

中文翻译：

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输电太阳能发电场的负序电流注入

集成太阳能发电给电力系统保护带来了独特的挑战。先前的研究发现，与传统发电机相比，基于逆变器的资源具有不同的故障响应。故障电流幅值的降低以及负序和零序电流的缺失会从根本上影响电力系统的保护方式。这封信研究了来自传输连接的太阳能发电场的负序电流注入。这封信使用现场记录的数据，通过分析逆变器如何响应故障，揭示了太阳能发电场的负序电流注入行为。此外，本文还研究了负序电流如何影响保护继电器中使用的负序方向元件。