TRANSMISSION AND DISTRIBUTION

Rugged Terrain, Severe Winters Place Special Demands on Fleet Equipment

One of the 10 generating plants operated jointly by Ontario Power Generation and the New York Power Authority (NYPA) is the St. Lawrence-FDR Power Project, a hydroelectric generating facility on the St. Lawrence River. The NYPA's 16 generating units at the plant can produce over 900,000 kilowatts of electricity, more than enough to light a city the size of Washington, DC. Power from the facility is distributed throughout the state of New York everywhere from New York City to Niagara Falls plus seven neighbouring states.

The extensive transmission network combined with the beautiful yet rugged terrain and long, severe winters in the vast area surrounding the town of Massena, New York where the facility is headquartered, place special demands on NYPA's crews and the equipment in their fleet. It was the ice storm of 1998 that provided the ultimate test of equipment, however. To replace the many lines and towers knocked down during the storm, the NYPA rented two truck-mounted aerial work platforms. The machines were Bronto Skylift model S-180HDT (heavy-duty telescoping) booms capable of 180-ft. working height and having 1,000-lbs. platform capacity.

Within the parameters of an emergency situation, the aerial work platforms operated flawlessly and handled everything they were asked to do. In fact, the reliability and safety of the rental units were such that within a year a new S-180HDT was purchased and added to the NYPA fleet.

As Guy Lannis, vehicle maintenance supervisor at the NYPA St. Lawrence-FDR Project said, "The Bronto's have more backup safety devices than any machines I've seen. All possible points of failure have a backup system. We can count on them in an emergency situation."

Today, it's not the only Bronto aerial work platform in the fleet. The transmission maintenance crews also needed an aerial work platform that could navigate the steep, remote terrain where many NYPA transmission towers are located.

Having had success with these machines, NYPA turned to another experienced vendor, Hydraulic Industries Corporation of suburban Montreal, Quebec seeking a combination of the two. Known as HICO, the company is a custom manufacturer of low ground pressure tracked vehicles and has provided NYPA with the base unit for such diversified products as dump boxes, cranes, and personnel carriers. HICO and Bronto worked together to create a machine that would meet NYPA's requirements. The final design consisted of mounting a Bronto S-111MDT (medium duty telescoping) aerial and torque box to a HICO HT15-HFS undercarriage.

While HICO and Bronto did the design work and supplied the components, assembly of the unit was done by Hinkel Equipment of Philadelphia, PA. Hinkel has had extensive experience in installation of aerials to chassis, and their personnel worked alongside Bronto factory representatives from Finland to complete the installation.

The newest Bronto in the NYPA's fleet is some machine. Powered by a Cummins diesel, it has 60 per cent climbing gradeability; and with its 40-in. treads fitted with grouser bars, it can handle 40 per cent sidehill gradeability. It uses a front wheel, hydrostatic drive system, weighs 55,000 lbs. yet it's loaded ground pressure is only 4.34 psi. On the other hand, tire mounted machines exert ground pressure on the order of 60 psi and higher.Its performance capabilities mean that the machine can travel over the ground to reach most of the towers in the NYPA's service area no matter how seemingly inaccessible. And getting to them doesn't take forever with a ground speed that is over three times faster than any other track type aerial. Both machines are so versatile they are used throughout New York State on all of NYPA's 1200 circuit miles of 115-kV, 230-kV, 345kV and 765-kV transmission lines.

The new unit is NYPA's only crawler mounted aerial work platform with outriggers, and they provide it with unique capabilities. The outriggers are independently controlled using the machine's hydraulic system and are designed with a longer stroke to handle steeper grades. The benefit to the users is that the machine does not have to be on a level surface to be operated -- it can be positioned on a slope, then the outriggers can be extended to level the unit using the controls inside the cab. Once leveled, the boom can be raised and work performed. With all four outriggers fully deployed, the boom has 360° rotation, When the machine is "short jacked", i. e. the outriggers are fully deployed on one side, interlocks are activated so the boom can only be extended on the side where the two outriggers have been set.

Short jacking is a useful feature when working in confined areas like substations and especially when working along side a road where fully extending the two "roadside outriggers" would mean blocking an additional traffic lane.

The standard Bronto S-111MDT has 111-ft. working height, 620 lbs. platform capacity and 72-ft. horizontal reach. The unit supplied to NYPA has an optional extended reach jib boom that extends to 78 ft., but limits platform capacity to 400 lbs. -- still plenty of capacity for a lineman and equipment.

NYPA's new unit was delivered in the fall of 2000 and immediately put to use running lines and changing out insulators in rural upstate New York. It hasn't faced the devastation of a severe ice storm yet, and Lannis says that he hopes that it never has to be used for a crisis like the one that originally got him acquainted with Bronto's quality and reliability.