Benchmarking Distribution Power Quality at BGE

Transcription

1 Benchmarking Distribution Power Quality at BGE Dewane Daley Engineer Baltimore Gas & Electric Company

2 Large Scale Benchmarking Projects at BGE Distribution System Power Quality Assessment Project (DSPQ Project) Distribution substation voltage quality monitoring Customer Quad4+ and PQNode Power Quality Monitoring Project Customer-side power quality monitoring

3 DSPQ Project Commissioned in Project Goals Obtain statistics on the magnitude, duration and frequency of sags, swells, transients and harmonic distortion typical of BGE s system. Benchmark results against those of the EPRI DPQ Project and other existing standards. Develop standards/guidelines for power quality on BGE distribution system.

4 Site Selection Methodology System population of 340 distribution buses. Project population of 40 distribution buses. Bus selection criteria was based on a. Feeder Value - net revenue from all downstream loads. b. Feeder Problem - one year bus momentary and sustained interruption data.

5 Sample Breakdown Total: 340 distribution buses Value Breakpoint: $0.6 Million Problem Breakpoint: 200 interruptions High Value Low High Population: 33 (9.7%) Monitored: 14 (3.5%) Population: 43 (12.6%) Monitored: 10 (25%) Problem Population: 88 (2.4%) Monitored: 10 (25%) Population: 176 (52%) Monitored: 6 (15%) Low

6 Data Collection Began on March 1, Involved monitoring of 40 distribution feeders (buses) using BMI 8010 PQNodes. Three (3) years of PQ disturbances and steady state samples collected to-date constituting a 4.5 Gigabyte database.

7 Substation PQNode 13.8 kv 34.5 kv

8 Lessons Learned - Voltage Sags Most sags were less than 40% relative to nominal and lasted less than 10 cycles. 35% of sags greater than 30% relative to nominal were associated with faults causing momentary interruptions. Frequency of sags greater than 30% relative to nominal provided a fair measure of system performance (SARFI 70 ).

9 SARFI 70 Project Definition - frequency of occurrence of voltage sags below 70% of nominal per feeder per 30 days aggregated over intervals of 1-minute. Calculated using EPRI PQView software. EPRI SARFI incidents per feeder per 30 days.

10 SARFI - Potential Future Used Used as a factor in allocating planning and maintenance dollars. Used as a tool for educating customers on realistic supply expectations. Develop customer contracts.

11 Lessons Learned - Harmonic Distortion Average THD at substation bus - 1.7%. Average TDD at substation bus - 1.9%. Monitoring at the substation bus provided little indication of harmonic distortion on distribution feeders. IEEE 519 adopted as reference but not enforced for customers.

12 Lessons Learned - Transients 83% were believed to be capacitor switching related. Clusters occurred from 4 AM to 6 AM, 4 PM to 6 PM and from 11 PM to 1 AM. Capacitor banks are used extensively across distribution system for reactive support.

13 Customer PQNode Project Currently involves 8010 PQNodes at 10 key customer sites. Two sites has since been enhanced with Powerdigm (TM) technology providing some before and after data. Allows for customer benchmark against BGE and EPRI SARFI index.

14 Quad4 Project Involves PSI Quad4 Plus revenue meters with power quality options. Installed at 850 primary metered customers. Provides measure of voltage sags and swells downstream of substation bus. Allows for customer benchmark against BGE and EPRI SARFI index.

15 Power Quality on the Intranet Implementation of EPRI WebPASS and PQWeb for PQNode data analysis. Migration of Quad4 Plus data to intranet via corporate network.

16 Benchmarking Distribution Power Quality at BGE Dewane Daley Engineer Baltimore Gas & Electric Company