ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 ANNUAL ELECTRIC TRANSMISSION AVAILABILITY PERFORMANCE REPORT Prepared by PG&E for CALIFORNIA INDEPENDENT SYSTEM OPERATOR (CAISO) PERFORMANCE YEAR 2019 2019 Electric Transmission Annual Availability Performance Report 1 PACIFIC GAS AND ELECTRIC COMPANY ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 TABLE OF CONTENTS Page 1. Availability Performance and CAISO Maintenance Standards 3 2. Performance Year 2019 4 3. How Control Charts Are Created 8 4. How Control Charts Are Used to Monitor Performance 9 5. Discussion Why Performance May Be Outside Control Chart Limits 10 6. Discussion on Improving Performance 25 7. Control Charts 32 8. Summary Outage Data 39 9. Original Control Charts from CAISO 52 2019 Electric Transmission Annual Availability Performance Report 2 PACIFIC GAS AND ELECTRIC COMPANY ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 1 1. AVAILABILITY PERFORMANCE AND CAISO MAINTENANCE STANDARDS 2 This annual report to the California Independent System Operator (CAISO or ISO) is prepared in accordance with Appendix C of the Transmission Control 3 Agreement (TCA) between each Participating Transmission Owner (PTO) such as Pacific Gas and Electric Company (PG&E) and CAISO. Section 4.3 of Appendix C 4 (Updated as of January 13, 2013) entitled CAISO TRANSMISSION MAINTENANCE STANDARDS states: 5 “Each PTO shall submit an annual report to the CAISO . describing its Availability Measures performance. This annual report shall be based 6 on Forced Outage records. All Forced Outage records shall be submitted by each PTO to the CAISO and shall include the date, start time, end 7 time affected Transmission Facility, and the probable cause(s) if known.” 8 The Availability Measure Targets are defined in Appendix C as “The Availability performance goals established by the ISO”, which are essentially the control 9 chart limits described and shown later in this report. 10 The purpose of the ISO Maintenance Standards is to promote safe, reliable and cost-effective electric transmission service consistent with the requirements of 11 California Assembly Bill 1890. A fundamental precept behind these standards is that the adequacy and effectiveness of a PTO’s maintenance of its electric 12 transmission system can be gauged by monitoring transmission availability performance. This performance is characterized by calculating three measures 13 (indices) related to “forced” outages (see Section 3 of this report for what constitutes a forced outage) on all CAISO-controlled circuits within a voltage class. A 14 majority, but not all, of PG&E transmission circuits have been assigned as being under CAISO control. Two indices measure the relative frequency of outages – 15 Annual Average Forced Outage Frequency (FREQUENCY) and Annual Proportion (PROPORTION) of Circuits with No For ced Outages. A third index measures the 16 duration of those outages – Annual Average Accumulated Forced Outage Duration (DURATION) for those Circuits with Forced Outages. As with all processes or 17 systems, variations in annual performances as defined by these three indices are inherent and expected. Control charts can be helpful in indicating whether 18 variation is due to common (i.e., random) causes, or to special (i.e., assignable) causes, and whether the electric transmission system is in a state of statistical 19 control. If the system is in a state of control, then maintenance practices are presumed to be adequate and effective. However, if a control chart indicates a 20 system is not in statistical control, then special cause(s) is likely and maintenance practices by the PTO may need review. 21 This report presents the control charts as calculated by CAISO using outage data submitted by PG&E and then jointly reconciled for any discrepancies through 22 performance year 2019. The report also shows results of applying 48 tests to the 12 charts (4 tests per chart) to help determine whether annual performance 23 for each of four voltage classes is improving, degrading, or in a state of statistical control. 2019 Electric Transmission Annual Availability Performance Report 3 PACIFIC GAS AND ELECTRIC COMPANY ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 1 2. PERFORMANCE YEAR 2019 2 After reconciliation with CAISO and excluding the outages below described under the header “EXCLUDED OUTAGES”, there were 1,179 unplanned forced 3 outages documented in 2019 with an accumulated facility outage duration (capped, see Section 3 below for definition of capped) equal to 555,327 minutes. 4 These 2019 results were more than the corresponding numbers for 2018, i.e., 996 unplanned outages and 482,215 accumulated minutes. 5 There are 905 circuits that were reported as CAISO-controlled for this report. PG&E has approximately 45 more transmission lines defined as “breaker to 6 breaker” that are not considered CAISO-controlled. The PG&E transmission grid also has numerous “tap lines” that are radial extensions of a main transmission 7 line. These tap lines or “taps” typically serve larger customers taking service at a transmission voltage level (i.e., >50,000 volts). If a tap itself has a fault or 8 interruption, then the resulting unplanned outage is credited to the main transmission line. 9 FIGURE 2-1 is a Pareto chart showing the spread of outages over the 905 circuits in 2019. The chart shows 244 transmission lines (27.0%) accounted for 80% of 10 the unplanned forced outages. Additionally, 453 of the 905 circuits (50.1%) had zero unplanned forced outages in 2019. 11 FIGURE 2-2 is a Pareto chart showing the spread of outage durations over the 905 circuits in 2019. It shows that 12.4% of the lines account for 80% of the 12 facility outage minutes. 13 Section 7 of this report has further discussion of performance year 2019, which ended up overall being an excellent year as measured by the control charts. 14 CAPPED OUTAGES: 15 In 2019 there were 37 outages (9 fewer than last year 2018) that exceeded 4,320 minutes in duration and, for the purpose of calculating line availability, had 16 their duration re-set to or capped at 72 hours and classified as “C” as defined on page 6 of the CAISO Maintenance Procedure No. 2 (Outage Data File Format 17 for the ISO). Of these 37 capped outages in 2019, 16 were in the 69kV class, 15 in the 115kV class, 3 in the 230kV class and 3 in the 500kV class. Of the 46 18 capped outages last year 2018, 21 were in the 69kV class, 15 in the 115kV class, 9 in the 230kV class and 1 in the 500kV voltage class. 19 Causes of the capped outages in 2019 included only 1 due to wildfire (Kincade Fire), 6 circuit breaker failures, 6 late notifications (further described later in this 20 report), 4-line equipment failures, 6 substation equipment problems (including relays) and 2 tree failures from outside the right-of-way. 2019 Electric Transmission Annual Availability Performance Report 4 PACIFIC GAS AND ELECTRIC COMPANY ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 1 2. PERFORMANCE YEAR 2019 (cont’d) 2 FIGURE 2-1 3 4 FIGURE 2-2 5 2019 Electric Transmission Annual Availability Performance Report 5 PACIFIC GAS AND ELECTRIC COMPANY ANNUAL ELECTRIC TRANSMISSION AVAILABILITY REPORT: 2019 1 2. PERFORMANCE YEAR 2019 (cont’d) 2 EXCLUDED OUTAGES: 3 Section 4.1.3 of Appendix C of the Transmission Control Agreement between PG&E and CAISO – i.e., “outages which are caused by events outside PG&E’s 4 electric transmission system (e.g., caused by another electric utility system encroaching into our grid, by equipment owned by a transmission-served customer 5 or owned and operated by an independent power producer (IPP), or an emergency request from a California agency such as CAL FIRE) or which can be 6 demonstrated to have been caused by earthquakes” – can be considered “excludable” and not included in calculating transmission line availability results. 7 Transmission Maintenance Procedure No. 5 (Classifying Forced Outages) supplements Appendix C by stating in Section 5.3 that “The ISO and PTOs want to 8 encourage the safe operation of the ISO grid; therefore, it is their intention to encourage safe work practices. The concern of reducing the number of Forced 9 Outages should not affect the safety of personnel or the general public.” Section 5.4 of this maintenance procedure supplements Section 5.3 by providing 10 specific examples in its Table-1 “Examples of Outage Classification for Common Events”. Example 9 in this table states the following: “Late notification on 11 Transmission Line Circuit outage request and the request impacts safety” is considered to be “Not a Forced Outage”. 12 Due to the devastating statewide wildfire season in 2017, PG&E developed Public Safety Power Shutoff (PSPS) protocols as an additional precautionary 13 measure to reduce the risk of wildfire ignition by utility equipment failures. Beginning with the 2019 wildfire season, PG&E expanded its PSPS program to 14 include all electric lines that pass through high fire-threat areas – both distribution and transmission. Because PG&E’s electric grid relies on power lines working 15 together to provide service, any of its more than 5 million customers could have power shut off, and power will remain off until weather conditions that 16 precipitated the call for PSPS execution subside and de-energized facilities are patrolled to ensure they can be safely restored. Because of the public safety 17 aspect of PSPS and per sections 5.3 and 5.4 in Maintenance Procedure No. 5, all PSPS events in 2019 (essentially 12 days of outages) were excluded for the 18 purpose of calculating the control charts for transmission line availability. 19 In 2019 there were 402 unplanned forced outages classified as “X”, i.e., excludable. Of those 402 events, 353 (87.8%) were PSPS events, hence a net of 49 20 excludable events that were not PSPS related.