Severe damage to distribution poles, transmission towers, and substations can result. Especially in the West, the central Mississippi valley, the coastal area of South Carolina, and southern Alaska and Hawaii ( Figure 3.3), the potential for disruption of major power system equipment by earthquake is significant.
Moving through Figure 3.1 from left to right, the first point is labeled E for earthquake. REVIEWING THE CAUSES OF OUTAGES Earthquake The chapter then makes a number of general findings and recommendations related to both human and natural threats to the power system. The next section reviews the major causes of outages depicted in Figure 3.1, beginning with those for which operators have the least warning and ending with those for which they have the most. Systems-both human and technical-must be built prior to grid failure to allow the responders to assess the extent of failure and damage, dispatch resources effectively, and draw on established component inventories, supply chains, crews, and communications. Good planning and preparation are essential to mitigating, ameliorating, and recovering from major outages effectively. For example, repairs can begin immediately after a tornado has passed, but flooding following a hurricane can delay the start of repairs for weeks and impede restoration efforts. The timing of repairs is different depending on the cause. Similarly, concrete poles may be more resistant to wind but offer no clear advantage or disadvantage in restoration. Of course a coffer dam does nothing to guard against the effects of earthquake or cyber attack. Building a coffer dam around a transformer may make it more resistant to flooding, but by limiting access for heavy equipment it can also make it harder to complete repairs when it actually fails.
For example, good substation design with clear separation of functions makes the substation more resistant to damage and helps repair crews.
Some actions serve both strategies, some serve one but not the other, and some serve one while inhibiting the other. It is also important to differentiate between actions designed to make the grid more robust and resilient to failure (e.g., wind resistant steel or concrete poles rather than wood poles opaque fences around substations to protect against damage from firearms) and those that improve the effectiveness of recovery (e.g., preemptive powering down of select pieces of the system to minimize damage). Strategies must be crafted with awareness and understanding of the temporal arc of a major outage, as well as how this differs from one type of event to another. DIFFERENT CAUSES REQUIRE DIFFERENT PREPARATION AND HAVE DIFFERENT CONSEQUENCESīuilding a strategy to increase system resilience requires an understanding of a wide range of preparatory, preventative, and remedial actions and an awareness of how these actions impact planning, operation, and restoration over the entire life cycle of different kinds of grid failures. Figure 3.2 categorizes the range of damages that may result after a disruption occurs. Figure 3.1 categorizes disruptions by the amount of advance warning that operators and others are likely to receive and the amount of time it takes to recover. Two of the most important differences are as follows: (1) how much warning system operators have that a disruption is coming so they can take protective action, and (2) how much of the physical and cyber control systems that make up the power system remain operative once the disruption has passed. The causes of outages differ in a number of important ways. As noted in Chapter 1, given the numerous and diverse potential sources of disruption, it is impressive that relatively few large-area, long-duration outages have occurred. The Many Causes of Grid Failure INTRODUCTIONĪ wide variety of events can cause disruption of the power system.
0 kommentar(er)
