A ROD CONTROL HYBRID
Transcript of A ROD CONTROL HYBRID
ADVANCED ROD CONTROL HYBRID ROD CONTROL POWER CABINET REPLACEMENT CONTROL SYSTEM
BACKGROUND
The Westinghouse Solid State Rod Control System
(SSRCS) has been in operation at many plants for over 30
years. This system has been very reliable but obsolescence
concerns are increasing and personnel experience for the
analog control system is difficult to maintain in the modern,
digital world. The system also has limited diagnostics and
can be time-consuming to troubleshoot, increasing
downtime.
For new plant applications, Westinghouse has deployed the
Digital Rod Control System (DRCS) to twenty new plants to-
date, which are in various stages of startup. While possible
to replace the Westinghouse SSRCS with a complete
DRCS, this is a challenging single outage installation, and
may be a higher risk proposition relative to outage
schedule.
To this end, Westinghouse has developed a drop-in
replacement for the existing SSRCS power cabinet analog
control card chassis that leverages the features and
functions of the DRCS, while maintaining the cabinets,
system architecture and power electronics. This new hybrid
of a digital control system and existing power electronics
provides a simplified path forward from analog to digital
control. This system is the Westinghouse Advanced Rod
Control Hybrid.
SYSTEM DESCRIPTION
Westinghouse Advanced Rod Control Hybrid is
Westinghouse’s third generation digital rod control system
that incorporates over twenty years of digital rod control
experience – from the Microprocessor Rod Control System
(MRCS) installed in Sizewell B to the new generation of
AP1000® plant and APR1400 DRCS installations.
At its base installation, the system consists of an electronics
control assembly that takes the place of the existing analog
control cards and replaces the Phase Transformer network.
This new system reduces the total card count from 20 total
cards (seven types) per power cabinet to nine total active
control cards (three types) and one built in backplane
extender card. These three standard cards will be used
across all systems utilizing Westinghouse Advanced Rod
Control Hybrid, including Combustion Engineering (CE)
plants, allowing for synergies in the fleet-wide spare part
program. The existing -24VDC power supplies are no longer
required, and the auctioneering diode assembly is replaced.
The new cards are industrial grade, Institute of Electrical
and Electronics Engineers (IEEE)-based, IPC-A-610 Class
2 printed circuit cards, with modern components based
around an industry standard, industrial safety grade, ARM
Real-Time microcontroller.
Figure 1-1 – Westinghouse Advanced Rod Control Hybrid Microcontroller Card – Current Regulating Controller Card (CRC)
Because the system is microcontroller-based, coil timing is
moved from the logic cabinet into the power cabinet,
removing the need for current order surveillance. A
simplified, single-fault tolerant control scheme is used that
works in conjunction with the OvationTM
Logic Cabinet Rod
Control Upgrade. This will re-use existing cabinet wiring so
installation will not require additional hardwired signals to be
run from the logic cabinet to the power cabinets. All that is
required is a single fiber-optic connection to each new
electronic control assembly.
TRUE DOUBLE HOLD
Each set of cards is capable of controlling up to four SCR
bridges. As such, using this hybrid, the single movable
gripper silicon controlled rectifier (SCR) bridge and support
circuity can be replaced with three individual bridges, which
will allow for true double hold. This removes the chance of
a single fault on the stationary gripper causing a rod drop or
slip. This also removes the need for the DC hold cabinet, as
holding can be maintained on the movable gripper while the
stationary gripper is de-energized.
Additionally, the existing single set of phase transformers is
replaced with two redundant, simplified phase transformers.
This removes another single fault and allows the movable
gripper to retain phase crossing and subsequently holding
in the event of complete or partial failure of stationary
gripper power.
Figure 1-2 - Existing SSRCS Control Cards (Right Bay)
Figure 1-3 – New Westinghouse Advanced Rod Control Hybrid Control Cards (Right Bay)
CONTROL AND DIAGNOSTICS
With the capability of a localized microcontroller, cabinet
parameters are continuously monitored and displayed on an
Ovation workstation. This includes, but not limited to:
Detailed alarm information
Coil current and voltage
Cabinet temperature
Calculated holding gripper temperature
Advanced maintenance modes are also available for
troubleshooting and testing, including the ability to exercise
all signals and system logic/software without M-G set power
and loads.
Figure 1-4 and Figure 1-5 show sample system status
displays. Ovation displays can be tailored to the customer’s
needs and plant specific Human Factored Engineering
(HFE) programs.
Ethernet communication enables setpoint modifications to
be accomplished via soft display.
Single rod motion is coordinated via soft display, and
existing control room lift disconnect switches can be
removed or abandoned in place.
W-ARCHPOWER CABINET OVERVIEW
PLANT UNIT 1DISPLAY TITLE
FEB 11, 201813:54:07
1ACSCDE 2AC
2BD 1BD
ROD CONTROL MAIN MENU
ALARM RESET
RESET
NON-URGENT
URGENT
LNK
SIM
MOVABLE GRIPPERCRC ID09
NON-URGENT
URGENT
LNK
SIM
STATIONARY GRIPPERCRC ID10
NON-URGENT
URGENT
LNK
SIM
LIFTCOIL
CRC ID11
NON-URGENT
URGENT
LNK
SIM
MOVABLE GRIPPERCRC ID06
NON-URGENT
URGENT
LNK
SIM
STATIONARY GRIPPERCRC ID07
NON-URGENT
URGENT
LNK
SIM
LIFTCOIL
CRC ID08
NON-URGENT
URGENT
LNK
SIM
MOVABLE GRIPPERCRC ID12
NON-URGENT
URGENT
LNK
SIM
STATIONARY GRIPPERCRC ID13
NON-URGENT
URGENT
LNK
SIM
LIFTCOIL
CRC ID14
NON-URGENT
URGENT
LNK
SIM
MOVABLE GRIPPERCRC ID03
NON-URGENT
URGENT
LNK
SIM
STATIONARY GRIPPERCRC ID04
NON-URGENT
URGENT
LNK
SIM
LIFTCOIL
CRC ID05
NON-URGENT
URGENT
LNK
SIM
MOVABLE GRIPPERCRC ID00
NON-URGENT
URGENT
LNK
SIM
STATIONARY GRIPPERCRC ID01
NON-URGENT
URGENT
LNK
SIM
LIFTCOIL
CRC ID02
URGENT
NON-URGENT
ROD CONTROL POWER CAB OVERVIEW
ROD CONTROL CRC SETPOINTS
ALARMS
ROD CONTROL CRC SETPOINTS
STEPPING
ROD CONTROL CRC SETPOINTS
SYSTEM
LOGIC CABINET
28.5
CABINET TEMP
°C
45.2
CABINET HUMIDITY
%RH
ROD CONTROL COIL
TEMPERATURE
Figure 1-5 –Overall System Status Display
CRC: 1AC SG CRC ID01
ERRANT CURRENT ERROR
ADC ERROR
BUSY NEVER CLEARED
EXCESS RIPPLE ERROR
FAULT OUT
FAULT IN
SINGLE POWER SUPPLY FAIL
M/G SET VOLTAGE ERROR
M/G SET PHASE TIMING ERROR
M/G SET PHASE PERIOD ERROR
59.9
M/G SET FREQUENCY
Hz
NON-URGENT
CBA1 – COIL INFORMATION
COIL CURRENT ENGAGEMENT TIME
45.2 V
COIL 1 584 ms4.45 A
COIL 2 584 ms4.45 A
COIL 3 584 ms4.45 A
COIL 4 584 ms4.45 A
COIL VOLTAGE
104.2 °
FIRING ANGLE
M/G SET INFORMATION
CRC STATUS INFORMATION
M/G SET VOLTAGE
PHASE A 150.12 VAC
CBC1 – COIL INFORMATION
COIL CURRENT ENGAGEMENT TIME
45.2 V
COIL 1 584 ms4.45 A
COIL 2 584 ms4.45 A
COIL 3 584 ms4.45 A
COIL 4 584 ms4.45 A
COIL VOLTAGE
104.2 °
FIRING ANGLE
SBA1 – COIL INFORMATION
COIL CURRENT ENGAGEMENT TIME
45.2 V
COIL 1 584 ms4.45 A
COIL 2 584 ms4.45 A
COIL 3 584 ms4.45 A
COIL 4 584 ms4.45 A
COIL VOLTAGE
104.2 °
FIRING ANGLE
PHASE B 150.12 VAC
PHASE C 150.12 VAC
POWER SUPPLY
PS1 24.2 VDC
PS2 24.1 VDC
5.55
PHASE PERIOD
ms
28.5
CARD CAGE TEMP
°C
0.2
LOOP TIME
msMAIN
0.1ms 0.1 ms
0.5ms 0.1 ms
1.0ms 0.2 ms
DOOR OPEN
EXCESS TEMPERATURE
MISSING CARDGFD
MISSING CARDSBC
STEP DEMAND ERROR
EXTREME ANGLE ERROR
ROD MOTION ERROR
CHECKSUM ERROR
LOW HOLDING CURRENT
BUSY IN
BUSY OUT
MAINTENANCE HOLD
FIXED FIRING ANGLE
FIXED CURRENT
CYCLING MODE
SIMULATION MODE
MECHANISM ENGAGED
STEP COMPLETE
ABORT STEP
MAINTENANCE MODE
SINGLE ROD MOTION
CRDM1
CRDM2
CRDM3
CRDM4
GRP A
CRDM1
CRDM2
CRDM3
CRDM4
GRP B
CRDM1
CRDM2
CRDM3
CRDM4
GRP C
-
ERROR CODE
1000ms 100 ms
W-ARCHCRC STATUS
PLANT UNIT 1DISPLAY TITLE
FEB 11, 201813:54:07
URGENT ALARM SIMULATION MODE
ON OFF
STATIONARY GRIPPER CYCLING
MODE
ON OFF
MAINTENANCE HOLD
ON OFF
INDIVIDUAL CARD ALARM RESET
RESET
FIXED FIRING ANGLE
ON OFF
FIXED FIRING ANGLE
170.0 °
FIXED CURRENT
ON OFF
FIXED CURRENT
0.0 A
Figure 1-4 –Stationary Gripper CRC Status Display
CURRENT PROFILE
CAPTURE
Westinghouse Advanced Rod Control Hybrid
captures current profiles for every step the
system takes, and transmits then to a
computer for archival in a database. This
database can be accessed via the
Westinghouse Current Profile Viewer tool,
shown in Figure 1-6.
Troubleshooting is simplified by viewing the
actual trace that caused the alarm. The trace
is retrieved by group, date and time, and
eliminates the need to attempt to recreate
the condition with a recorder attached, which
may be difficult for intermittent error
conditions.
Profile data can be archived for future
predictive analysis of Control Rod Drive
Mechanism (CRDM) operation.
INSTALLATION OPTIONS
Beyond the base system installation, additional power cabinet components such as fuses, resistors and terminal blocks
can be upgraded as needed/desired with the modern equivalents used in the DRCS. This flexible approach will allow long-
term system upkeep that is consistent with the utilities operational, maintenance and financial strategies.
BENEFITS OVERVIEW
All timing is determined by the microcontroller digitally; there is no phase shift network required. This drives less
hardware associated with phase cross detection.
Reliability of modern components, and modern manufacturing processes.
Enhanced diagnostics capabilities.
Distributed microcontroller architecture enables low-level fault detection and reporting.
Redundant features and fault detection/recovery features prevent dropping of rods due to single failures in power
circuitry or control electronics.
All printed circuit cards are “hot swappable.”
Special CRDM individual coil exercise feature removes “crud” buildup upon operator demand.
The power cabinet monitors and analyzes the current flow to the CRDM coils to confirm that the CRDM grippers
operate during rod motion. This confirms that one CRDM gripper latches prior to the other gripper unlatching during
rod motion, preventing dropped rods due to sluggish CRDM operation.
Computer communications between the power cabinets and the logic cabinet support remote diagnostics,
maintenance and adjustments to the rod control system.
The system provides coil current traces – capturing, monitoring and saving for future reference. Misstep or alarm
conditions are captured without trying to recreate the condition with additional steps.
Standard interface to plant data network (Ovation) system is used.
Single rod motion using soft control.
Eliminates Termi-point terminations from the card cage, and associated preventative maintenance inspections.
Figure 1-6 –Current Profile Viewer
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©2018 Westinghouse Electric Company LLC. All Rights Reserved
NA-0167 / June 2018