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Publicado: 1 de abril de 2011
Actions Before... and After a Flood
Substation Protection and Recovery from Weather-Related Water Damage
Nicholas Abi-Samra and Wayne Henry
Digital Object Identifier 10.1109/MPE.2010.939950 Date of publication: 23 February 2011
52
IEEE power & energy magazine
©iSTOCKPHOTO.COM/ED HUGHES
1540-7977/11/$26.00©2011 IEEE
march/april 2011
F
FLOODING CAN CAUSE SEVERE DAMAGE TOSUBSTAtion equipment and lead to interruptions in service continuity and widespread outages. This article covers some of these impacts and how to harden substations against them. It also discusses field-proven means of recovering from such events. We include a detailed discussion of a case history: a 1993 flood that resulted in US$10–15 billion in losses. The best practices that emerged from theefforts of the major U.S. utility that dealt with it, Union Electric (UE, now known as AmerenUE), are also described. Weather can have a significant impact on the asset management, planning, and operation of transmission and distribution systems, especially in the case of a utility with a large footprint that can be affected by different types of extreme weather. Of these extreme weather events, fewinflict more punishing damage on substation equipment than floods. Flooded substations are affected very differently than those hit by other extreme weather events, such as ice and windstorms. Restoring flooded substations takes much longer than restoring a downed power line damaged by ice or wind and requires different restoration procedures and personnel. Even minute quantities of moisture and dirtcontamination can render some electric equipment inoperable or lead to catastrophic failure. Given the large amounts of water, rust, and mud left trapped in a piece of substation equipment following total submersion, repair of that equipment becomes a sizable task. Flooding becomes a problem for substations when the amount of water reaching drainage network exceeds its capacity. The aim of thisarticle is to present a sampling of hardening and restoration measures for substations subjected to flooding.
Case History: The 1993 Union Electric Flood
Background
The summer of 1993 was exceptionally wet in the midwestern United States. Record rainfall (a series of downpours of more than eight inches) washed down the Missouri and Mississippi rivers, which flooded beyond their 100-year marks.These wet conditions soaked a large portion of the UE service area, which is bisected by the two rivers. Hardest hit was the St. Louis metropolitan area, home to 80% of UE’s customer base. The flood caused between US$10 billion and US$15 billion in damage. Of UE’s 1,300 stations, 19 were affected by rushing waters, and several suffered extensive damage. Some stations experienced floodwater depths ofmore than ten feet (see Figure 1). In addition to the damage to the substations, the flood affected rail lines and halted barge traffic, both of which restricted coal
march/april 2011
IEEE power & energy magazine
53
(a)
delivery to three of UE’s four coal-fired plants (representing 70% of the company’s power). That required UE to import a third of its power needs from the neighboringsystems. The flooding occurred during a period of extreme hot weather conditions in many of the surrounding states, and on 22 July, the transmission systems in the southern MidAmerica Interconnected Network (MAIN) and East Central Area Reliability Coordination Agreement (ECAR) regions experienced overloads due to heavy north-south electricity transfers during extreme hot weather in the SoutheasternElectric Reliability Council (SERC) region. Southern ECAR also experienced voltage depressions. Heavy transmission transfers were driven by high demand due to the sustained high temperatures across the southern United States and generation outages in the Midwest caused by flooding in the Missouri and Mississippi River basins. In addition, there were coal conservation efforts at UE and elsewhere...
Substation Protection and Recovery from Weather-Related Water Damage
Nicholas Abi-Samra and Wayne Henry
Digital Object Identifier 10.1109/MPE.2010.939950 Date of publication: 23 February 2011
52
IEEE power & energy magazine
©iSTOCKPHOTO.COM/ED HUGHES
1540-7977/11/$26.00©2011 IEEE
march/april 2011
F
FLOODING CAN CAUSE SEVERE DAMAGE TOSUBSTAtion equipment and lead to interruptions in service continuity and widespread outages. This article covers some of these impacts and how to harden substations against them. It also discusses field-proven means of recovering from such events. We include a detailed discussion of a case history: a 1993 flood that resulted in US$10–15 billion in losses. The best practices that emerged from theefforts of the major U.S. utility that dealt with it, Union Electric (UE, now known as AmerenUE), are also described. Weather can have a significant impact on the asset management, planning, and operation of transmission and distribution systems, especially in the case of a utility with a large footprint that can be affected by different types of extreme weather. Of these extreme weather events, fewinflict more punishing damage on substation equipment than floods. Flooded substations are affected very differently than those hit by other extreme weather events, such as ice and windstorms. Restoring flooded substations takes much longer than restoring a downed power line damaged by ice or wind and requires different restoration procedures and personnel. Even minute quantities of moisture and dirtcontamination can render some electric equipment inoperable or lead to catastrophic failure. Given the large amounts of water, rust, and mud left trapped in a piece of substation equipment following total submersion, repair of that equipment becomes a sizable task. Flooding becomes a problem for substations when the amount of water reaching drainage network exceeds its capacity. The aim of thisarticle is to present a sampling of hardening and restoration measures for substations subjected to flooding.
Case History: The 1993 Union Electric Flood
Background
The summer of 1993 was exceptionally wet in the midwestern United States. Record rainfall (a series of downpours of more than eight inches) washed down the Missouri and Mississippi rivers, which flooded beyond their 100-year marks.These wet conditions soaked a large portion of the UE service area, which is bisected by the two rivers. Hardest hit was the St. Louis metropolitan area, home to 80% of UE’s customer base. The flood caused between US$10 billion and US$15 billion in damage. Of UE’s 1,300 stations, 19 were affected by rushing waters, and several suffered extensive damage. Some stations experienced floodwater depths ofmore than ten feet (see Figure 1). In addition to the damage to the substations, the flood affected rail lines and halted barge traffic, both of which restricted coal
march/april 2011
IEEE power & energy magazine
53
(a)
delivery to three of UE’s four coal-fired plants (representing 70% of the company’s power). That required UE to import a third of its power needs from the neighboringsystems. The flooding occurred during a period of extreme hot weather conditions in many of the surrounding states, and on 22 July, the transmission systems in the southern MidAmerica Interconnected Network (MAIN) and East Central Area Reliability Coordination Agreement (ECAR) regions experienced overloads due to heavy north-south electricity transfers during extreme hot weather in the SoutheasternElectric Reliability Council (SERC) region. Southern ECAR also experienced voltage depressions. Heavy transmission transfers were driven by high demand due to the sustained high temperatures across the southern United States and generation outages in the Midwest caused by flooding in the Missouri and Mississippi River basins. In addition, there were coal conservation efforts at UE and elsewhere...
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