Reclose Blocking Automated
Risk Reduction Category
Technology Description
Automatic reclosers improve reliability for customers by allowing the circuit to attempt to clear faults without human intervention. Depending on utility configuration, reclosers may attempt fault clearing two or three times, typically within approximately 30 seconds, before locking out. If these automated attempts fail to clear the fault, then crews must be dispatched to assess the condition. While reclosers are very common, they may pose a risk of wildfire ignition in fire-prone regions of the country. Utilities who operate in these regions may temporarily disable the reclose feature of specific automated reclosers during the fire season.
Thus, the term reclose blocking refers to the prevention of automatic reclosing. This can be done remotely via communications (wired, wireless) or through sending a troubleshooter (or crew) to change the configuration of the recloser controls. This type of adjustment is termed manual reclose blocking in that it is either an ON (block reclosing) or OFF (allow reclosing) via a ‘command’ to the recloser and the setting will persist until changed. Further, the decisions on where and when to make these adjustments are based on utility policy and/or operators’ assessment of risk. In contrast to manual reclose blocking, where a decision to enter (and exit) a period of reclose blocking is done on a seasonal basis, automated reclose blocking is more aligned with current conditions.
Because wind, humidity, and other risk drivers for wildfires are dynamic in nature, protection schemes should also be dynamically controlled and responsive. Operators need to quickly disable reclosing and sectionalize areas of high fire risk based on changing conditions. Operators can use real-time fire risk models to make these decisions.
Technical Readiness (Commercial Availability)
Manual control of reclose blocking is a common practice in fire-prone areas. California utilities in fire-risk areas are operationally blocking reclosing seasonally and within specific rural areas of their service territory. When intelligent and communicating reclosers are installed, manual reclose blocking is fairly straightforward. However, some rural circuits may have non-communicating reclosers, requiring truck rolls. Automated reclose blocking is emergent and can be practiced in various forms, where the frequency, duration, and thresholds may vary widely from one utility to another. There is currently no standard for implementation, and doing so is ultimately driven by the risk posture of the utility. Any automated reclose equipment that communicates over SCADA can be used to implement an automated reclose blocking use case, including the following and many others:
Eaton
https://www.eaton.com/us/en-us/products/medium-voltage-power-distribution-control- systems/reclosers.html
G&W Electric
https://www.gwelectric.com/products/distribution-reclosers-and-overhead-switches
S&C Electric
https://www.sandc.com/en/products--services/products/?c=326
Schweitzer Engineering Labs (SEL)