Inside an underground, secret, security-protected room, men sit in front of computer video screens. With a device that looks like a small flashlight - a light pencil - one of these engineers can merely touch the video screen and pinpoint or correct an electric power problem.

Located somewhere in Montgomery County, the Potomac Electric Power Company Consolidated Control Center is the nerve core of the electric companY. When a power failure cuts off lights in the White House, the Capitol or even the District Building, these men get the call on a hotline - they restore power.

Power outage complaints are also funneled to this secret center - resembling the Pentagon War Room - from residents of the District and those in sections of Maryland and Virginia.

Using a map that fills a huge wall, engineers constantly refer to the pulsating system of energy. "We can look at the map and screens and tell where problems are arising," said Walter A. Johnson, manager of the control center.

An engineer touches the video screen with the light pencil. A maze of red and green lines appear. The red lines indicate a live flow of electric current, while green lines show where power is out.

Another touch to the screen, near green lines, and a display of "trouble complaints" appears giving names, times and kinds of problems consumers in that area face.

One engineer pointed to a green-lined section on the screen. "If I were to touch that spot, which is located at a power station near Baltimore, it would send power through that line and electrocute all the men working in that section, he said.

According to Johnson, the cen- ter, which cost $12 million to build, has not yet had to cope with a major problem such as last summer's wind storm that knocked out power to thousands of local area homes.

If such a problem should occur again, the center will be better able to monitor outage problems and dispatch repairmen to the proper locations, he said.

"If the problem is a matter of bypassing a generator, we can make the repair right here in the control center. But if it is a matter of lines down, we have to get our servicemen to the problem area quickly," said Johnson.

And when other major electric power companies are in trouble, Johnson said the control center can buy or sell power to those companies with a touch of the light pencil to the video screen.

"The reason for secrecy is obvious," stated a PEPCO spokesman who said the Washington metropolitan area would have no power for days if a terrorist successfully attacked the center.

With the White House, the Capitol, the Pentagon and other majorgovernment facilities on line with PEPCO, "it's no wonder that the security system is overseen by the military," the spokesman said.

Inside the control center, other measures of security are clearly spelled out. Everything is done in a combination of twos. There are two sets of computers, two communication systems, two power systems and an extra system to control the entire PEPCO operation.

"We like to think we are prepared for any kind of emergency," a PEPCO spokesman said.