SOW Ref B Theory of Operation and SCADA Instructions.pdf

USCG Rescue 21 Program

Point Pigot RFF Upgrades

Theory of Operation and SCADA Instructions

Contents

A. OVERVIEW

1. Introduction

2. Overview of Modifications

B. RBS CONTROL PANEL

1. Allen Bradley PLC System

2. Voltage Regulators

3. Local Operators

4. Fuel Monitoring Panel

C. DETACHMENT SCADA SYSTEM

1. Overview

2. Navigating the Ignition SCADA System

3. SCADA Screens

Overview Screen

Trends Screens

Alarm Screens

A. OVERVIEW

1. Introduction

Between November, 2018 and February, 2019, RMC Engineering modified the

USCG Point Pigot RFF control system. Prior to the modifications, the system was comprised of a main rotary battery system (“RBS”) control panel with dual engine controllers and an Omron PLC rack to control two three-phase 208/120 VAC propane generators. Additionally, there was a remote I/O panel in the communications hut that monitored the propane tank fuel levels. The engine controllers consisted of circuit boards with digital and analog I/O capable of monitoring and controlling the voltage output of the generators.

Prior to the modifications, the engine controllers failed and the site went dark.

Subsequently, RMC was contracted to restore power to the site.

2. Overview of Modifications

RMC replaced both engine controllers and the Omron PLC system with a single

Allen Bradley PLC control system. The new system has a single PLC processor and two I/O racks in the existing RBS and an additional remote I/O rack to replace the fuel monitoring system in the communications hut:

• I/O Rack 1: Replaces existing I/O Rack in RBS Panel.

• I/O Rack 2: Replaces Omron PLC System.

• Fuel Panel I/O Rack: Replaces Existing Fuel Monitoring Remote I/O Rack.

B. RBS CONTROL PANEL

1. Allen Bradley PLC System

An Allen Bradley CompactLogix 1769-L30ER PLC has replaced the engine controllers and Omron PLC while maintaining the majority of the site’s same control and monitoring capabilities. The PLC performs all logic related to generator functionality. This includes:

• Monitoring site feedback;

• Running generators;

• Operating power hut dampers and inlet fan; and

• Communicating with Ignition SCADA system at the Douglas Detachment.

In order to monitor site feedback and control generator and damper operations, the PLC communicates with the remote I/O racks in both the RBS Panel and the

Fuel Monitoring Panel via an Ethernet network.

2. Voltage Regulators

Two Stamford SX460 voltage regulators replaced the existing voltage regulators that were part of the Mechron RBS system. The voltage regulators provide the generators with an excitation current which is what produces the 208/120 VAC generator output voltage. The generators’ output voltage varies proportionally with the magnitude of the excitation current.

The voltage regulators are equipped with potentiometers that control the generator output voltage setpoint. Using voltage feedback from the outputs of the generators, the voltage regulators modulate the excitation current in order to maintain the generator setpoint voltage.

The generator feedback is also the power source for the voltage regulators and, therefore, disconnecting this feedback from the regulators precludes the generators from producing a voltage. The voltage feedback for Generator A and

Generator B passes through normally open contacts of newly installed relays R1 and R2, respectively. The PLC program only energizes R1 or R2 when a generator is called to run.

3. Local Operators

Each generator has operators installed on the main RBS control panel that provide the generators with local control capabilities. Each generator has the following operators:

• Start Button

• Stop Button

• Off-Auto Selector Switch

The functionality of these operators is as follows:

• When the Off-Auto Selector Switch is in the Off position, the program will not allow the generator to run.

• When the Off-Auto Selector Switch is in the Auto position, the program will allow the generator to run in o 1) Remote Mode from the Ignition SCADA system and o 2) automatic mode based on the start and stop setpoints set in the

Ignition SCADA system.

• When the Off-Auto Selector Switch is in the Auto position, both generators are off, and the Start Button operator is pressed, the PLC will start the generator. The generator’s normal functionality will resume upon starting.

• When the Off-Auto Selector Switch is in the Auto position, a generator is running, and the Stop Button operator is pressed, the PLC will shut off the generator. The generator’s normal functionality will resume after stopping.

Additionally, there is one E-Stop operator on the left door of the main RBS control panel. When depressed, this E-Stop breaks the circuit to the fuel control relay for both generators, which in turn breaks the circuit to the generators’ fuel solenoid and the ignition coil. Therefore, when the E-Stop is depressed, the generators cannot run until the E-Stop is pulled back out. The E-Stop has a plastic cover that can be locked with a padlock as part of a lock-out tag-out procedure.

4. Fuel Monitoring Panel

The Fuel Monitoring Panel monitors the propane tank levels. The control panel passes 5 VDC out to hall-effect level sensors and the DC voltage level returned for each tank is proportional to the level of that tank. The voltage signals are inputs to the remote I/O rack. The remote I/O rack passes these level values to the PLC in the main RBS control panel via an Ethernet cable that is run between the generator hut and the communications hut.

C. DETACHMENT SCADA SYSTEM

1. Overview

The main means of monitoring and control of the Pigot Point power system is through the Ignition SCADA system at the Douglas Detachment. The SCADA system currently offers the following capabilities for Point Pigot RFF:

• Monitoring generator status;

• Monitoring environmental dampers and inlet fan status;

• Monitoring propane tank levels;

• Viewing historical trends;

• Viewing and clearing alarms;

• Modifying generator system setpoints; and

• Remotely starting and stopping generators.

2. Navigating the Ignition SCADA System

The Ignition SCADA system is setup using a two-tier navigational system. The top tier of tabs selects the RFF site. After selecting the site tab, the second tier of tabs selects the desired screen pertaining to that site.

Image 1. Two-Tier Navigation System.

3. SCADA Screens

Overview Screen

The Overview screen is the main screen used to monitor and control the site.

Image 2. Overview Screen with both generators offline.

The Overview Screen offers the following control:

• Generator mode selection:

o Auto Mode: Auto mode is selected by pressing the Auto Button. In auto mode, the generator starts when it is the lead generator and the battery bank low-voltage threshold has been met. The generator stops when the high-voltage shutoff and the low-current shutoff thresholds have been met. If the Swap-Mode setting is enabled, the generators automatically alternate as lead generator after each run.

o Remote Mode: Remote mode is selected by pressing the Remote Button. In remote mode, the Start and Stop buttons become enabled, allowing a single generator to be remotely started when both generators are offline and stopped when running. In remote mode, the generator will stop after the Remote Runtime threshold has been reached, which prevents a generator from inadvertently being left on in Remote Mode.

• Generator setpoints:

o Clicking the Setpoints button brings up a Generator Setpoints popup (Image 3). This popup allows for the modification of the following settings:

▪ Low-voltage Start;

▪ High-voltage Stop;

▪ Low-Current Stop;

▪ Remote Runtime; and

▪ Swap Mode.

Image 3. Generator Setpoints popup.

The Overview Screen displays the main system components, including the charge current, battery-bank voltage, and fuel tank levels. The status of the environmental controls is also displayed, with a green overlay indicating that a damper is open or that the fan is running.

Trends Screens

The Trends Screen allows the operator to browse historical data. The operator can select from the available data points (“pens”) and then select the desired date range. This will display all pertinent logged data from a local SQL database.

This is useful for troubleshooting and analyzing site performance over time.

The Fuel Trends Screen offers the same functionality as the Trends Screen but only shows the fuel tank level pens. Only five fuel tanks are currently reading values and, therefore, are the only pens displayed.

Image 4. Trends Screen. The date range selected shows the previous four generator runs.

Image 5. Fuel Trends Screen displaying the five functioning fuel tank levels over a ten-day period.

Alarm Screens

The Alarms Screen displays the status for current alarms. Any alarm that becomes active will display on this screen until the alarm becomes inactive and the alarm has been acknowledged by an operator. Alarms are acknowledged by selecting an alarm and pressing the Acknowledge Button at the bottom of the screen.

The Alarm History page displays a journal of historical alarms. Detailed information regarding each alarm is displayed here, including the alarm name and the alarm event, i.e., active, cleared, and acknowledged.

The Alarm Configuration page allows configuration of alarm settings related to the generator. Alarms can be disabled and alarm time-delays can be set.

Additionally, setpoints for analog alarms can be configured on this page.

Image 6. Alarm Screen without any alarms displayed, indicating that no active alarms and that all previous alarms have been acknowledged.

Image 7. Alarm History Screen displaying a Low Oil-Pressure Alarm becoming active and acknowledgment.