Incident details
Operator, cause, commodity and consequences with raw source fields.
GD incident on 2020-10-06 — MN
Operator
Northern States Power Co Of Minnesota
Cause
Incorrect Operation
Commodity
Natural Gas
Program
GD
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$887
Incident datetime
2020-10-06 12:00
Report number
Location
MN, WASHINGTON
Narrative
Crew was on site to repair a leaking flange at a regulator station. The crew was in the process of removing a bypass line and returning the system to normal. This process involved reopening a block valve and putting it back into service. When doing this, the sense line inadvertently remained in the closed position. This lead to the pressure being measured on the trapped gas in the bypass line, not the downstream pressure. The crew thought they had returned the system to normal. After approximately 30 minutes, the gauge had dropped only 1/4 lb. The crew expected the pressure to drop more rapidly. They did some troubleshooting and checked the gauge in the vault (which was monitoring downstream pressure) and saw the gauge read 1lb. They realized immediately that they were not reading the downstream pressure, but in fact the trapped pressure in the sense line. The crew opened the trap and the pressure dropped from 18lbs to 1lb instantly. The system was shut down, riser valves turned off, sytem re-pressurize and then perform relights. Xcel energy reviewed applicable policies and procedures with front line employees involved with this event. Xcel energy is developing additional training that is focused on what specific work requires a written procedure.
Detailed record list
Occurred At
2020-10-06 12:00:00
Year
2020
Report Received Date
2020-11-06 00:00:00
Iyear
2020.0
Report Number
20200112.0
Supplemental Number
35044.0
Report Type
Supplemental Final
Operator Id
31636
Name
Northern States Power Co Of Minnesota
Operator Street Address
414 Nicollet Mall
Operator City Name
Minneapolis
Operator State Abbreviation
MN
Operator Postal Code
55402
Local Datetime
2020-10-06 12:45:00
Time Zone
Central
Daylight Savings Ind
No
Location Street Address
675 Gentry Ave
Location City Name
Oakdale
Location County Name
Washington
Location State Abbreviation
MN
Location Postal Code
55128
Location Latitude
44.57308
Location Longitude
-92.59186
Flow Cont Main Valve Ind
Yes
Nrc Rpt Datetime
2020-10-06 16:12:00
Nrc Rpt Num
1289146
Additional Nrc Report Numbers
1289305
Commodity Released Type
Natural Gas
Unintentional Release
0.0
Intentional Release
0.0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Ignite Ind
No
Num Pub Evacuated
0.0
Incident Identified Datetime
2020-10-06 12:00:00
Communication State Fed Ind
No
On Site Datetime
2020-10-06 12:00:00
Federal
No
Location Type
Utility Right-Of-Way / Easement
Incident Area Type
Underground
Incident Area Subtype
In Underground Enclosed Space (E.g. Vault)
Depth Of Cover
36.0
Other Underground Facilities
Yes
Crossing
No
Pipe Facility Type
Investor Owned
System Part Involved
District Regulator/metering Station
Material Involved
Steel
Steel Seam Type
Other
Steel Seam Type Details
Unknown
Release Type
Other
Release Type Details
No Release Was Involved In This Incident
Class Location Type
Class 3 Location
Est Cost Oper Paid
0.0
Est Cost Prop Damage
887.0
Est Cost Emergency
253120.0
Est Cost Other
0.0
Gas Cost In Mcf
0.0
Est Cost Unintentional Release
0.0
Est Cost Intentional Release
0.0
Prpty
254007.0
Commercial Affected
50.0
Industrial Affected
0.0
Residences Affected
1480.0
Num Persons Hosp Not Ovnght
0.0
Num Injured Treated By Emt
0.0
Num Resident Building Affctd
1480.0
Num Business Building Affctd
50.0
Accident Psig
1.0
Normal Psig
18.0
Mop Psig
20.0
Mop Cfr Section
192.619(A)(4)
Maop Established Date
1989-03-14 00:00:00
Accident Pressure
Pressure Did Not Exceed Maop
Gas Odorized System Type
Other
Gas Odorized Sys Other Detail
Odorized By Transmission Operator
Gas Odorized Lvl Not Msrd Ind
Yes
Scada In Place Ind
No
Accident Identifier
Local Operating Personnel, Including Contractors
Operator Type
Operator Employee
Investigation Status
No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate)
Investigation Status Details
Scada was operating within parameters at the time of the event.
Employee Drug Test Ind
Yes
Num Employees Tested
3
Num Employees Failed
0
Contractor Drug Test Ind
Yes
Num Contractors Tested
3
Num Contractors Failed
0
Cause
Incorrect Operation
Cause Details
Valve Left Or Placed In Wrong Position, But Not Resulting In An Overpressure
Operation Type
Valve Left Or Placed In Wrong Position, But Not Resulting In An Overpressure
Related Other Ind
Yes
Operation Related Details
Crew Was Bypassing A Regulator Station To Repair A Leaking Flange. Work Was Stopped And The Bypass Valve Was Inadvertently Left In The Closed Position, Causing The Pressure At The Monitoring Point To Give A False Value.
Category Type
Other Maintenance
Operator Qualification Ind
Yes
Qualified Individuals
Yes, They Were Qualified For The Task(S)
Preparer Name
E******** K*******
Preparer Title
Principal Gas Compliance Consultant
Preparer Email
E*******************@x*********.com
Preparer Telephone
651-229-2282
Authorizer Name
C********** A****
Authorizer Title
Manager Pipeline Compliance And Standards
Authorizer Telephone
303-517-3298
Authorizer Email
C******************@x*********.com
Narrative
Crew was on site to repair a leaking flange at a regulator station. The crew was in the process of removing a bypass line and returning the system to normal. This process involved reopening a block valve and putting it back into service. When doing this, the sense line inadvertently remained in the closed position. This lead to the pressure being measured on the trapped gas in the bypass line, not the downstream pressure. The crew thought they had returned the system to normal. After approximately 30 minutes, the gauge had dropped only 1/4 lb. The crew expected the pressure to drop more rapidly. They did some troubleshooting and checked the gauge in the vault (which was monitoring downstream pressure) and saw the gauge read 1lb. They realized immediately that they were not reading the downstream pressure, but in fact the trapped pressure in the sense line. The crew opened the trap and the pressure dropped from 18lbs to 1lb instantly. The system was shut down, riser valves turned off, sytem re-pressurize and then perform relights. Xcel energy reviewed applicable policies and procedures with front line employees involved with this event. Xcel energy is developing additional training that is focused on what specific work requires a written procedure.
| Occurred At | 2020-10-06 12:00:00 |
|---|---|
| Year | 2020 |
| Report Received Date | 2020-11-06 00:00:00 |
| Iyear | 2020.0 |
| Report Number | 20200112.0 |
| Supplemental Number | 35044.0 |
| Report Type | Supplemental Final |
| Operator Id | 31636 PHMSA Enforcement |
| Name | Northern States Power Co Of Minnesota |
| Operator Street Address | 414 Nicollet Mall |
| Operator City Name | Minneapolis |
| Operator State Abbreviation | MN |
| Operator Postal Code | 55402 |
| Local Datetime | 2020-10-06 12:45:00 |
| Time Zone | Central |
| Daylight Savings Ind | No |
| Location Street Address | 675 Gentry Ave |
| Location City Name | Oakdale |
| Location County Name | Washington |
| Location State Abbreviation | MN |
| Location Postal Code | 55128 |
| Location Latitude | 44.57308 Google Maps OpenStreetMap |
| Location Longitude | -92.59186 Google Maps OpenStreetMap |
| Flow Cont Main Valve Ind | Yes |
| Nrc Rpt Datetime | 2020-10-06 16:12:00 |
| Nrc Rpt Num | 1289146 NRC Report How to search |
| Additional Nrc Report Numbers | 1289305 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 0.0 |
| Intentional Release | 0.0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Ignite Ind | No |
| Num Pub Evacuated | 0.0 |
| Incident Identified Datetime | 2020-10-06 12:00:00 |
| Communication State Fed Ind | No |
| On Site Datetime | 2020-10-06 12:00:00 |
| Federal | No |
| Location Type | Utility Right-Of-Way / Easement |
| Incident Area Type | Underground |
| Incident Area Subtype | In Underground Enclosed Space (E.g. Vault) |
| Depth Of Cover | 36.0 |
| Other Underground Facilities | Yes |
| Crossing | No |
| Pipe Facility Type | Investor Owned |
| System Part Involved | District Regulator/metering Station |
| Material Involved | Steel |
| Steel Seam Type | Other |
| Steel Seam Type Details | Unknown |
| Release Type | Other |
| Release Type Details | No Release Was Involved In This Incident |
| Class Location Type | Class 3 Location |
| Est Cost Oper Paid | 0.0 |
| Est Cost Prop Damage | 887.0 |
| Est Cost Emergency | 253120.0 |
| Est Cost Other | 0.0 |
| Gas Cost In Mcf | 0.0 |
| Est Cost Unintentional Release | 0.0 |
| Est Cost Intentional Release | 0.0 |
| Prpty | 254007.0 |
| Commercial Affected | 50.0 |
| Industrial Affected | 0.0 |
| Residences Affected | 1480.0 |
| Num Persons Hosp Not Ovnght | 0.0 |
| Num Injured Treated By Emt | 0.0 |
| Num Resident Building Affctd | 1480.0 |
| Num Business Building Affctd | 50.0 |
| Accident Psig | 1.0 |
| Normal Psig | 18.0 |
| Mop Psig | 20.0 |
| Mop Cfr Section | 192.619(A)(4) View CFR 49 §192 |
| Maop Established Date | 1989-03-14 00:00:00 |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Gas Odorized System Type | Other |
| Gas Odorized Sys Other Detail | Odorized By Transmission Operator |
| Gas Odorized Lvl Not Msrd Ind | Yes |
| Scada In Place Ind | No |
| Accident Identifier | Local Operating Personnel, Including Contractors |
| Operator Type | Operator Employee |
| Investigation Status | No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate) |
| Investigation Status Details | Scada was operating within parameters at the time of the event. |
| Employee Drug Test Ind | Yes |
| Num Employees Tested | 3 |
| Num Employees Failed | 0 |
| Contractor Drug Test Ind | Yes |
| Num Contractors Tested | 3 |
| Num Contractors Failed | 0 |
| Cause | Incorrect Operation |
| Cause Details | Valve Left Or Placed In Wrong Position, But Not Resulting In An Overpressure |
| Operation Type | Valve Left Or Placed In Wrong Position, But Not Resulting In An Overpressure |
| Related Other Ind | Yes |
| Operation Related Details | Crew Was Bypassing A Regulator Station To Repair A Leaking Flange. Work Was Stopped And The Bypass Valve Was Inadvertently Left In The Closed Position, Causing The Pressure At The Monitoring Point To Give A False Value. |
| Category Type | Other Maintenance |
| Operator Qualification Ind | Yes |
| Qualified Individuals | Yes, They Were Qualified For The Task(S) |
| Preparer Name | E******** K******* |
| Preparer Title | Principal Gas Compliance Consultant |
| Preparer Email | E*******************@x*********.com |
| Preparer Telephone | 651-229-2282 |
| Authorizer Name | C********** A**** |
| Authorizer Title | Manager Pipeline Compliance And Standards |
| Authorizer Telephone | 303-517-3298 |
| Authorizer Email | C******************@x*********.com |
| Narrative | Crew was on site to repair a leaking flange at a regulator station. The crew was in the process of removing a bypass line and returning the system to normal. This process involved reopening a block valve and putting it back into service. When doing this, the sense line inadvertently remained in the closed position. This lead to the pressure being measured on the trapped gas in the bypass line, not the downstream pressure. The crew thought they had returned the system to normal. After approximately 30 minutes, the gauge had dropped only 1/4 lb. The crew expected the pressure to drop more rapidly. They did some troubleshooting and checked the gauge in the vault (which was monitoring downstream pressure) and saw the gauge read 1lb. They realized immediately that they were not reading the downstream pressure, but in fact the trapped pressure in the sense line. The crew opened the trap and the pressure dropped from 18lbs to 1lb instantly. The system was shut down, riser valves turned off, sytem re-pressurize and then perform relights. Xcel energy reviewed applicable policies and procedures with front line employees involved with this event. Xcel energy is developing additional training that is focused on what specific work requires a written procedure. |
External Resources
PHMSA pipeline safety insights.
Product
Features
Company
All rights reserved. Copyright © by ClearPHMSA