Overview...

Bridges Electric Automated Switching Solutions successfully meet the needs of electric utilities when it comes to remotely operated switches. All Bridges Electric Automated Switches include the following standard features:

• Motorized Switch - Manufactured as a true unitized switch - Completely factory assembled and adjusted
• Painted Aluminum Enclosure
• High Current Motor Solenoids
• Front Panel "Open" & "Close" Toggle Switches (For local initiation of switch commands)
• Local/Remote switch to select local front panel initiated switch commands, or Remote for remotely generated switch commands
• 24VDC Hawker Genesis sealed lead-acid battery
• 120VAC Power Switch to disconnect power to the DC Power Supply and to the control cabinet's heater module and motor assembly heater
• 24VDC Power Fuse to allow for electrical protection of the motor and provide for "locking out" switch control position
• 120VAC Heater Assembly
• Terminal Strips for terminating control points
• Mil-Spec Bulkhead Connectors (On motor housing and control cabinet) for motor power cable connection
• Output Contacts for status feedback
• Pre-wired Motor Control Cable with Mil-Spec Bulkhead connectors on each end for easy hook-up of control cabinet to switch motor
• Control Cabinet Manuals, Switch Unit Manuals, and other pertinent manuals for installation

Versatility...

Many other features/options are available with Bridges Electric Automated Switches. Bridges Electric packages systems utilizing RTU’s and communication hardware currently in use by the electric utility. In so doing, many of the communication difficulties commonly encountered when trying to adapt one system to the requirements of another is eliminated. We modify our base cabinet to mount specific hardware to meet the customers’ needs. With the expertise Bridges has in interfacing components and systems, this is a cost effective advantage. Bridges Electric has no standard supplier of RTU’s or communication hardware. We have installed systems utilizing RTU’s and communications from all the major suppliers. Bridges Electric can purchase everything and supply the entire package, or we can take advantage of the utility’s buying power and have them supply the high dollar items and include only a modest installation charge. In some cases the utility has elected to install the SCADA equipment themselves. In this case Bridges Electric supplies the AutoPak cabinet with space available on the back panel for the customer to mount the RTU and communication equipment.

Sensing...

Bridges Electric can offer line post current and voltage sensors mounted directly to the switch unit for 3Ø current and voltage monitoring (Topper Series only). These are required when a high degree of current and voltage accuracy is necessary. The Bridges Electric RCMS (Remote Current Monitoring System) is a cost effective alternative for current monitoring and fault detection. The RCMS maintains the full BIL of the switch by an air gap separation from the hot parts of the switch. Some utilities use only the RCMS fault detection function, not wanting to report analogs. If voltage monitoring is required, a transducer can be placed on the 120VAC cabinet power to provide a single phase voltage analog, or line post voltage sensors can be incorporated to the switch unit for 3Ø voltage monitoring.

Battery Load Tester...

Switch performance is greatly enhanced when incorporating the Battery Load Test Function offered by Bridges Electric. What makes up the Battery Load Tester is a programmable logic controller (PLC) or an RTU with programmable ladder logic capability, high current relay, and a power resistor. The controller will apply a resistive load to the battery and monitor the drop of the battery voltage in respect to time under load. Variables associated with this feature will be the minimum voltage at which a faulty battery condition is identified and time duration of the load test. Provisions for programming the load test interval are pre-programmed and can be varied. The high current relay is designed to carry the high current associated with the battery load test. A 1Ω, 300W load resistor is included to supply a current load on the battery. The battery load test feature is set up to generate an alarm to indicate a faulty battery.

Bridges Electric has been supplying electric utilities with reliable solutions for their Distribution Automation needs for many years. We offer a wide range of manual sectionalizing solutions where the individual devices (motorized switches) report status back to the master station and operations people determine the scope of the situation and open and close switches to take corrective action.

We also offer two other levels of automatic switch schemes. The Auto Sectionalizer system is similar to the manual sectionalizing solution but the Auto Sectionalizer utilizes an automatic program running algorithms for opening and closing the switch. This system commands a Bridges motorized switch to open by two selectable methods of fault detection, the VI method and the V method. The VI method monitors the source voltage and the load current, and after a time delay, opens the switch. The V method counts the number of loss of source events (i.e. breaker operations) and after a time delay, opens the switch.

Another level of automatic switch schemes offered by Bridges Electric is the new Auto Throwover (ATO). The ATO system utilizes two or three switches to maintain power to a critical load (restoration of power in seconds). The ATO system also accomplishes fault blocks allowing auto sectionalizing of the preferred feeder without closing the alternate source into the load side fault. Previous Bridges Electric ATO versions consisted of three control cabinets - A DC Control Cabinet at each switch and a centrally located ATO Controller. The new version of ATO offers two large ATO Control Cabinets set up in a master/slave arrangement. The interface between the ATO control cabinets is accomplished via fiber optics or radio (Interconnection among previous Bridges ATO Control Cabinets was achieved via hard wiring). The ATO system has the option for SCADA interaction for status and reporting as well as 3Ø current and voltage monitoring. Some of the major advantages of the ATO include:

• "Hard wiring" between the control cabinets of previous Bridges ATO's is eliminated - Communication among the new ATO design is achieved via fiber optics or radio
• SCADA interaction for status and reporting
• Sophisticated program that provides great flexibility of application
• Design minimizes the use of mechanical devices providing high level of dependability
• Extremely accurate solid state timers
• Controller commands multiple operation attempts if first attempt fails