Distribution System Measurements

Transcription

1 1.0 Introduction Distribution System Measurements Authors: Daniel Zimmerle, Cody Pickering, Colorado State University STATUS: Final This annex describes the design and execution of the distribution system measurements performed for the study. 2.0 Distribution System in the Study Area All distribution in the study area is operated by one company, who partnered with the study to make 100% of distribution systems in the study area available for screening and measurement. While GIS information for locations of pipeline and services were not shared, complete leak lists and site counts were shared with the study team. Figure 2-1 shows the distribution system pipelines in the study area. Figure 2-1: Distribution pipeline map for study area. Map image courtesy of CenterPoint Energy. Distribution lines are shown in blue; mains in red. 3.0 Study Design The field campaign did not include pipeline surveys. Instead, reported leaks were randomly selected from a comprehensive leak list provided by the partner company. Sites were chosen randomly from the operator s underground pipeline leak list. The leak list was primarily composed of class B and class C leaks (PHMSA classification) since Class A leaks must be repaired immediately as they pose a safety hazard. It is important to note that emissions rates from class A leaks are not necessarily larger than class B or C. Class A is defined by proximity to human activity and associated risk. 1 P a g e

2 For above-ground facilities, counties with large areas within the study area were given preference to counties with little total area. Once counties were selected facilities were measured in random order until allocated time was consumed or 100% of facilities were measured. All sites were well maintained with easy access to the study team and could be measured in any order. Facility types were broken down into Transmission/Distribution Transfer Stations (TDTS, Figure 3-1), metering and regulating (M&R, Figure 3-2) facilities and Customer Meters (Figure 3-3). The same method for screening and measurement applies to all facility types. Differences between facilities consist of use and size. TDTS have more components than M&R which, in turn, typically have more components than customer meters. In addition to difference in size, inlet pressures for each facility type also varies. TDTS drop transmission pipeline pressure, typically psia, to lower pressure for distribution to M&R stations where the pressure is further regulated before distribution to customer meters. In keeping with the GHGI and recent studies, difference in pressure is categorized by greater than 300 psi, between 100 and 300 psi, between 40 and 100psi and less than 40 psi. Figure 3-1 TDTS Figure 3-2 M&R Figure 3-3 Customer Meter As custody transfer locations, TDTS equipment is split into two sets, owned by the transmission and distribution operator, respectively. The study team did not have permission to do both sides of TDTS stations at onset of the field campaign, but this permission was obtained from the study s transmission partners soon after the campaign started. Due to the delay, not all TDTS measurements include on both sides of the station. 4.0 Measurement Methods Distribution measurements were also performed by GHD personnel, utilizing the same instrumentation as specified for gathering pipelines (see Annex 10). For distribution, measurements were limited to study team personal outfitted with a Heath Consultants RMLD and INDACO High-Flow. Since no pipelines were surveyed, screening was not performed by vehicle-mounted gas detectors (VMS), as was done for gathering pipelines. The study team surveyed each component at a facility with the RMLD and if an increased concentration was detected the component would be measured using a high-flow with either a plastic enclosure or cone to isolate the leak, depending upon the shape of the component. Pneumatic controllers were measured whenever present at a facility, also using the high-flow sampler. Measurements being taken with a high-flow and plastic bag attachment can be seen in Figure P a g e

3 Figure 4-1 High-Flow at TDTS Measurements performed on underground pipeline leaks were found by using the leak list supplied by the partner company. In most cases leaks had been marked by flags or tape by the partner company. However, if the tape or flag had been removed, dead vegetation often indicated where the leak was located. Measurements were performed utilizing a flux chamber and high-flow sampler, as shown in Figure 4-2. If leak location was not apparent or if the leak appeared to disperse wider than the enclosure, multiple measurements would be taken using the high flow and plastic enclosure in a gridded pattern. Figure 4-2: Flux chamber enclosure for measuring underground distribution leaks 5.0 Leak List Measurements Leaks are categorized by MAIN or SVCS. Services run off mains and take gas to customer s meters. In this case customer meters that were measured are categorized. Leak Rate (gch4/hr) Category County 3.53 SVCS White 3 P a g e

4 14.86 MAIN White 0.00 SVCS Faulkner 1.73 SVCS Faulkner 1.73 SVCS Faulkner 1.73 SVCS Faulkner SVCS Faulkner 1.73 MAIN Faulkner 1.73 SVCS Pope 1.73 SVCS Pope 0.00 SVCS Pope SVCS Pope 1.73 SVCS Pope MAIN Pope 0.00 MAIN White 0.00 SVCS White 0.00 SVCS White 0.00 MAIN White MAIN White SVCS White 0.00 MAIN Faulkner 6.0 Facility List Measurements Facilities measured in this study can be seen bellow they are categorized by M&R and TDTS where M&R are smaller substations in the area that reduce pressure and no not necessarily meter the gas. TDTS are larger stations that transfer gas from transmission companies to the distribution company. NA means not applicable and M&R Facilities were not connected to transmission facilities. NM stands for not measured. In four instances TDTS Stations transmission sides were not measured and at two TDTS stations the transmission side was not measured due to legal obligations. 4 P a g e

5 County Inlet Pressure (psi) Category Distribution Side Leak Rate (g CH4/hr) Transmission Side Leak Rate (g CH4/hr) Pneumatic Controllers (g CH4/hr) Facility Total (gch4/hr) WHITE 45 M&R 1.73 NA NA 1.73 WHITE 250 TDTS 0.00 NM NM 0.00 WHITE 83 M&R 0.00 NA NA 0.00 WHITE 85 M&R 0.00 NA NA 0.00 WHITE 85 M&R 0.00 NA NA 0.00 WHITE 86 M&R 0.00 NA NA 0.00 WHITE 86 M&R NA NA WHITE 120 TDTS 3.72 NM NM 3.72 WHITE 672 M&R 0.00 NA NA 0.00 WHITE 50 M&R 1.73 NA NA 1.73 WHITE 223 M&R 1.73 NA NA 1.73 WHITE 220 M&R 0.00 NA NA 0.00 WHITE 51 M&R 1.73 NA NA 1.73 WHITE 48 M&R 1.73 NA NA 1.73 FAULKNER 155 M&R 0.00 NA NA 0.00 FAULKNER 204 M&R 8.05 NA NA 8.05 FAULKNER 200 M&R 0.00 NA NA 0.00 FAULKNER 155 M&R 0.00 NA NA 0.00 FAULKNER 155 M&R 0.00 NA NA 0.00 FAULKNER 133 M&R 0.00 NA NA 0.00 FAULKNER 180 M&R 0.00 NA NA 0.00 FAULKNER 190 M&R 0.00 NA NA 0.00 FAULKNER 155 M&R 0.00 NA NA 0.00 FAULKNER 220 M&R 0.00 NA NA 0.00 FAULKNER 232 M&R 0.00 NA NA 0.00 FAULKNER 185 M&R 0.00 NA NA 0.00 FAULKNER 234 M&R 4.00 NA NA 4.00 FAULKNER 232 M&R 0.00 NA NA 0.00 FAULKNER 234 M&R 0.00 NA NA 0.00 FAULKNER 236 M&R 0.00 NA NA 0.00 FAULKNER 236 M&R 0.00 NA NA 0.00 FAULKNER 238 M&R 0.00 NA NA 0.00 FAULKNER 238 TDTS FAULKNER 137 M&R 0.00 NA NA 0.00 FAULKNER 342 TDTS FAULKNER 126 M&R 0.00 NA NA 0.00 FAULKNER 110 M&R 0.00 NA NA 0.00 FAULKNER 200 TDTS P a g e

6 FAULKNER 163 TDTS FAULKNER 411 TDTS FAULKNER 150 M&R 0.00 NA NA 0.00 FAULKNER 115 M&R 0.00 NA NA 0.00 FAULKNER 120 M&R 1.73 NA NA 1.73 FAULKNER 120 M&R 0.00 NA NA 0.00 FAULKNER 299 TDTS FAULKNER 180 M&R 1.73 NA NA 1.73 FAULKNER 180 M&R 0.00 NA NA 0.00 FAULKNER 197 M&R 0.00 NA NA 0.00 FAULKNER 150 M&R 0.00 NA NA 0.00 FAULKNER 180 M&R 0.00 NA NA 0.00 VANBUREN 240 TDTS 1.73 NM NM 1.73 VANBUREN 228 M&R 0.00 NA NA 0.00 VANBUREN 147 M&R 0.00 NA NA 0.00 VANBUREN 180 M&R 0.00 NA NA 0.00 VANBUREN 228 M&R 1.73 NA NA 1.73 VANBUREN 174 M&R 0.00 NA NA 0.00 VANBUREN 236 M&R 0.00 NA NA 0.00 VANBUREN 235 M&R 3.22 NA NA 3.22 VANBUREN 226 M&R 0.00 NA NA 0.00 VANBUREN 227 M&R 0.00 NA NA 0.00 VANBUREN 220 M&R 0.00 NA NA 0.00 VANBUREN 185 M&R 0.00 NA NA 0.00 VANBUREN 230 M&R 0.00 NA NA 0.00 VANBUREN 245 M&R 0.00 NA NA 0.00 VANBUREN 243 M&R 0.00 NA NA 0.00 VANBUREN 239 M&R 0.00 NA NA 0.00 VANBUREN 281 M&R 0.00 NA NA 0.00 VANBUREN 228 M&R 0.00 NA NA 0.00 VANBUREN 248 M&R 0.00 NA NA 0.00 VANBUREN 250 M&R 0.00 NA NA 0.00 VANBUREN 211 M&R 0.00 NA NA 0.00 VANBUREN 250 M&R 0.00 NA NA 0.00 VANBUREN 250 M&R 0.00 NA NA 0.00 CONWAY 91 TDTS 0.00 NM NM P a g e

7 CONWAY 150 M&R 0.00 NA NA 0.00 CONWAY 80 M&R 1.73 NA NA 1.73 CONWAY 91 M&R 0.00 NA NA 0.00 CONWAY 86 M&R 0.00 NA NA 0.00 CONWAY 81 M&R 0.00 NA NA 0.00 CONWAY 654 TDTS CONWAY 620 TDTS CONWAY 620 TDTS CONWAY 600 TDTS CONWAY 542 TDTS POPE 160 M&R 0.00 NA NA 0.00 POPE 434 TDTS POPE 165 M&R 1.73 NA NA 1.73 POPE 435 TDTS POPE 409 TDTS POPE 193 M&R 3.57 NA NA 3.57 POPE 160 M&R 0.00 NA NA 0.00 POPE 167 M&R 0.00 NA NA 0.00 POPE 100 M&R 0.00 NA NA 0.00 POPE 40 M&R 0.00 NA NA 0.00 POPE 78 M&R 0.00 NA NA 0.00 POPE 150 M&R 0.00 NA NA 0.00 POPE 158 M&R 0.00 NA NA 0.00 POPE 180 M&R 0.00 NA NA 0.00 POPE 166 M&R 0.00 NA NA 0.00 POPE 178 M&R 0.00 NA NA 0.00 POPE 428 TDTS POPE 113 M&R 0.00 NA NA 0.00 POPE 101 M&R 0.00 NA NA 0.00 CLEBURNE 385 TDTS CLEBURNE 840 TDTS CLEBURNE 385 TDTS CLEBURNE 385 TDTS CLEBURNE 45 M&R 0.00 NA NA 0.00 CLEBURNE 53 M&R 0.00 NA NA 0.00 CLEBURNE 95 TDTS P a g e

8 CLEBURNE 82 M&R 0.00 NA NA 0.00 CLEBURNE 222 TDTS CLEBURNE 44 M&R 0.00 NA NA 0.00 CLEBURNE 42 M&R 0.00 NA NA 0.00 CONWAY 49 TDTS FAULKNER 670 TDTS WHITE 440 M&R 0.00 NA NA 0.00 FAULKNER 375 TDTS NM FAULKNER 375 TDTS NM P a g e