Hope Creek Variable Frequency Drive 2018 Power Plant Simulation Conference Houston, TX January 14-18, 2018
Hope Creek Variable Frequency Drive Simulation John Stone Senior Engineer - CORYS
Presentation History Benefits Overview Hope Creek VFD Simulation Model Operation Close
History Early VFD applications began in 1960. With the evolution of high power solid state electronic parts, they are more widely used. Nine BWR nuclear sites use them for replacements of GE Motor Generator Sets driving Reactor Recirculation Pump Motors: Columbia (2), Browns Ferry (6), Hatch (4), Quad Cities (4), Brunswick(4), Limerick(4), Dresden (4), Peach Bottom (4), and Hope Creek(2) Millstone PWR nuclear site uses them for replacements of 10 Circulation Water Pump Drives. CORYS first full VFD simulation was done for Exelon Limerick in 2011 2012. 4
Benefits Typical energy savings 50% (Hope Creek 54.4%) Soft Starts - starting currents typically ½ of normal increases pump life Lower maintenance costs (solid state technology) No scoop tube which requires full speed drive from the MG Set motor VFD reduces speed, and thereby amps drawn
Overview Upgrade Steps Remove: MG Set and Scoop Tube speed control Retain without change: RR pump and motor Recirculation Pump Trip (RPT) breakers Retain with modifications: Supply breaker for the MG Set is reused for the VFD Modified to accept close and trip signals from the VFD 6
Overview - Original MG Set VFD VFD replaces MG Set and Scoop Tube The VFD converts the MV supply (7.2 KV) by converting it to DC, and then converting the DC to variable frequency AC
Hope Creek VFD Simulation Model
Hope Creek VFD Sim Model (2) Internal Liquid Coolant System The internal coolant system is modeled in XFLOW and is a new model in the Hope Creek simulator. The manual code for interfacing this model to the legacy code also handles pump cavitation, pump auto cycle, pump speed control (by flow), three way valve control (by outlet temperature), leak flow malfunction, and heat exchanger isolation.
10 Each VFD has a closed loop coolant system.
Two heat exchangers on top give up system heat to TACS. Two redundant pumps force flow through the power cells. An expansion tank provides suction pressure. 11
12 heat exchangers remove heat from the 12 power cells plus transformers. A 13 th heat exchanger removes heat from the cabinets. 12
Hope Creek VFD Sim Model TACS The internal coolant system is cooled by the existing Turbine Auxiliary Cooling System (TACS) modeled in XFLOW.
This shows a small portion of the TACS system. The four VFD heat exchangers (2 for each VFD) are in parallel with Turbine Building Chiller Condensers. They replace the 2 original MG Set Oil Coolers. 14
15 Remote functions allow isolation of the redundant heat exchangers
Hope Creek VFD Sim Model (4) Electrical The existing ThunderElectric model is modified to replace the MG Set loads with the VFD loads on the 7.2 KV buses. VFD Control power is supplied by two new 480 V distribution panels. Former support systems for the MG Sets are removed. These include: Lube oil pumps (2 for each MG Set) Vent fans (1 for each MG Set)
17 Replace MG Set
Add VFD distr pnl Removed 2 Oil Cooler Pumps Remove Vent Fan 18
Hope Creek VFD Sim Model (5) GRAPHICS Complete graphics for Instructor Station and Glass Panel Simulator for each VFD MCR HMI Local Cabinet HMI Local Cabinet Liquid Coolant System HMI MCR controls
20 MCR HMI
21 Local Cabinet HMI
22 Local Cabinet Liquid Coolant System HMI
Operation 1. Local Cabinet Liquid Coolant System HMI includes cycle coolant pumps Verifies backup is available Required by Surveillance Procedure 2. VFD Start Precharge 3. VFD Run Pump 4. Malfunction both Liquid Coolant Pumps 23
Local Cabinet Liquid Coolant System - Cycle Pumps 24
Operation (2) Start VFD A Precharge MCR Controls Monitor Precharge Screen 25
26 MCR Controls Start Precharge VFD A
27 MCR HMI Start Precharge VFD A
Operation (3) After Precharge, Run VFD A Pump 28
29 MCR Controls Run VFD A Pump
30 MCR HMI Run VFD A Pump
Operation (4) Fail both liquid coolant pumps Observe early annunciators Observe automatic power cell bypasses Observe low DC voltage causing trip of VFD A 31
32 MCR HMI First phase of loss of coolant pumps
33 HMI Alarms first phase of loss of coolant pumps
34 Local Cabinet Liquid Coolant System HMI during first phase of loss of coolant pumps
Operation (4) (Continued) Final phase of loss of coolant pumps malfunction This video starts after the power cells have exceeded normal temperature, about 2 and 1/2 minutes into the scenario. Examine annunciators after trip. 35
MCR HMI during last phase of loss of coolant pumps 36
HMI Alarms after last phase of loss of coolant pumps 37
Close Full simulation projects require detailed data. Many new products for nuclear power plants are data protected. Requires customer to develop contacts to provide good data. Good sources of data include: Siemens SOD (System Operations Document) Siemens O&M Volumes Customer Change Package Drawings FAT results for actual plant system Contacts with subject matter experts Videos of actual operation 38
Thanks / Credits Thanks to Mr. Mark Parrish at Hope Creek for providing the data and interpretation to make this project possible. THANK YOU ALL FOR YOUR KIND ATTENTION QUESTIONS? 39