200 likes | 213 Views
This system measures power quality to ensure harmonics do not flow back to the transmission system, based on IEEE-519 and IEEE-1453 standards.
E N D
AEP’s Virtual Wide Area Power Quality Measurement System using Energy Meters Prashant Kansal, Paulo C Cambraia, Nathaniel R Dunn October-12-2015, CIGRE USNC-Chicago
What is Power quality (ideally)? • Source: Should provide fixed 60 Hz voltage • Load: Should be linear i.e. should draw 60Hz current
source and Load • Grid is continuous-where is the source and the load? • Source: Power system at Point of Common Coupling (PCC) • Load: Any customer connected to the system Other Events: Solar Storm or EMP Large Industrial customers Convertor Based Loads and Generators
Why power quality ? Problems • Reduces insulation life-Increased chances of failure • Increased system losses-More heating • Network Resonance Issues- Temporary Over Voltages • Communication Interference-Noisy communication signals • EM relays mis-operation -Undesired tripping- Not an issue for AEP Solutions • Sink the harmonics to ground at the origin- Filters • Harmonics cancellation- Transformer connection • Static VAR Compensator- Voltage Flicker Bottom-line • Harmonics should not flow back into the system- Customers should resolve issues to meet PQ standards • If not taken care by a customer, utility has to resolve the issue-Other customers expect good PQ
AEP Power Quality standard • AEP standard is based on IEEE-519 and IEEE-1453 • IEEE-519: Practices and Requirements for Harmonic Control • IEEE-1453: Flicker Measurement design specifications Quantities based on IEEE-519 • Current Harmonics (1-40th) • Voltage Harmonics (1-25th) • THD for Current (THDI) • THD for Voltage (THDV) • Telecommunication Interference (weighted I*T) Quantities Based on IEEE-1453 • Voltage Flicker (PST and PLT)
AEP Power Quality standard • Ensure good power quality at sub-transmission and distribution system so that harmonics do not flow back to the transmission system • It is much easier to resolve PQ issues at the point of origin as compared to addressing the problem at the transmission level
PQ Monitoring system architecture Switchyard Pi Server Station Control House Telecommunication 7 7 7
Instrument transforms limitation • Response depends on loading, secondary cable, and manufacturer • Some CTs and PTs were tested at AEP **IEEE Transaction on Power Delivery Vol. 10, No. 4, October 1995
Communication requirements: protocol • Measurements from ION meters can be communicated using DNP or MODBUS protocols. • Current (3*40), Voltage (3*25), THDV (3), THDI (3), PST (3), PLT (3): Total 207 number of analog points are required. • Since DNP points are not available, we used Modbus as communication protocol. • Communicate data directly to Station Pi server so that we do not need to change RTU Point Assessment (RPA) file. • The data is sent using MODBUS protocol over TCP/IP.
Communication requirements: Physical Infrastructure • Various physical communication media available at substation are: Ethernet, Phone Lines, Cellular, MAS Radio, VSAT, MPLS, Ethernet. • Phone Lines: It’s a dial-up connection for recording energy transaction data. Also, ION meter does not make PQ information available at phone communication port. • Cellular connection: Cellular data is billed as per usage and is in-consistent. • MAS Radio: It does not connect to station router and is not suitable for TCP/IP communications. • VSAT:Can be used in some cases but may not have sufficient bandwidth. Typical bandwidth supported is 1-4 kbps. • Shared Ethernet or MPLS: Our best bet!
Communication requirements: bandwidth usage • Ethernet, MPLS, and VSAT are our preferred communications media. • Plot below shows the packet size and average bandwidth usage. • Based on Wireshark capture, average bandwidth usage is 0.5kbps.
Meter location selection A. Meter availability:Clearly, we need ION 8600A and 8650B meters. B. Communication Medium: Need Ethernet, MPLS, or VSAT C. AEP Owned Meter: Meter should be AEP owned D. AEP Owned Substation: Station should be AEP owned so that we can do installation and use the communication infrastructure. E. ERCOT Polled Settlement (EPS): If a meter is EPS meter, we do not consider it for upgrade (so far) because of regulatory reasons. F. CIP station: We do not make any changes to the CIP stations as well.
Acknowledgement • Richard Gutman • Sanjoy Sarawgi • Jeff Fleeman • Carlos Casablanca • John Mandeville • Schneider Team • Transmission Meter Operations Team • Bradford P Martin