Consolidated Edison Co. - the utility which most of the time supplies power to New York City and surrounding suburbs - is a study in what ails the power industry.

Con Ed hemorrhages over problems and pressures which smaller utilities suffer in manageable proportions. These range from faulty, aging equipment and rising fuel costs to harrassment by environmentalists, belaboring by politicians and oversight by a regulatory commission that swears by an antiguated code.

Con Ed's book assets of $6 billion rank second among utilities, only to American Telephone and Telegraph's. Last year the company earned $301 million on revenues of $2.9 billion, a respectable return. But these numbers mask still fundamentally shaky supports at the firm Fortune magazine dubbed in 1966 "The Company You Love to Hate."

That appellation appeared several months after the 1965 blackout of much of the Northwest. A federal investigation placed blame for the blackout on an error in judgment by engineers in Canada who overloaded U.S. circuits in attempting to adjust their own automatic switching equipment. A Con Ed engineer failed to pull a breaker switch that would have lessened the damage to New York's power grid.

In its report to the President about the crisis, the Federal Power Commission rebuked Con Ed. It wondered why there were neither automatic devices nor more precise guidelines for operators to handle such an emergency.

Further, the agency criticized the utility for the 13-hour delay in restoring services. It pointed to the company's reliance on slow-starting steam generators that would have provided electricity to restart huge, inert turbines.

The blackout was just one - although the most severe - of a series of outages that had plagued Con Ed customers. The utility's deficiencies had become legion. Since the mid-1950s, the company had lagged far behind other utilities in growth and earnings, and the men at the top had grown old and embattled, proud and thin-skinned.

By 1967, a new man was in charge. Charles F. Luce, a former undersecretary of the Interior, deliberated three weeks over whether to accept the job of Con Ed chairman, then decided he would for the sake of challenge and the big-city arena.

Luce stepped into office saying: "Our objective will be to make Con Edison first in all ways - but especially in service . . . We will strive to make it the cleanest, most reliable, best-looking, and most efficient electric system that can be designed."

Not long ago, when reminded of those words, Luce quipped, "I was naive."

In the past 10 years, Luce has led Con Ed through a number of reforms, among the most major being a total restaffing of the utility's top 30 jobs. This task was complicated somewhat by the power industry's no-raiding gentlemen's agreement, which explains why many of the people in charge at Con Ed today have retired military titles after their names.

Acting on a management consultant's recommendation, Luce decentralized the company to borough levels and computerized much of its paperwork. The purchasing and construction departments were overhauled, and efforts were made to recruit contractors - particularly minority-group contractors - outside normal combinations of companies that always bid on Con Ed jobs.

But running a utility in New York can be unlike running a utility anywhere else. The utility charges more for electricity than just about anyone else in the world, but the geography, political climate and economics of New York make the company's operating costs far higher, too.

About 90 per cent of the company's electrical load is distributed underground - a far higher proportion than in other big-city systems - and this increases the cost of maintenance and repair enormously. Labor is also more costly, and the cost is rising faster in New York than the national average.

An even greater problem is New York's heavy commercial load, which causes the utility to suffer a wide swing in demand for power from day to night. For a while, Con Ed tried to get householders to use more electricity at night so as to balance the load. They advertised the slogan, "To Stop a Thief, Light a Light."

Early in 1971, the company decided to end all sales promotion. Later, it embraced the cause of conservation with a "Save a Watt" campaign.

In the meantime, the company has added considerable generating capacity to its system since the 1965 blackout. To boost capacity as quickly as possible, Con Ed installed gas turbine generators, which use distillate oil or natural gas and are more expensive to operate than conventional equipment. The gas turbines generate a total of 2,285,000 kilowatts - about one-fifth of the system's entire capacity.

The original plan was to use the turbines to meet peak demands, but the company has been forced to use them for base-load capacity. The result, once again, is to boost unit costs.At the same time, Con Ed has been importing power into its system from cheaper outside sources and has sold several of its oldest generators.

Plans for nuclear plants have been delayed for environmentalists and federal licensing agencies. The most exasperating fight for Con Ed is over its Storm King plant, which environmentalists say threatens to destroy fish spawning grounds on the Hudson.

Such opposition has left Con Ed dependent largely on oil when most utilities are moving to coal and nuclear fuel. With its generators daily gulpting tens of thousands of low-sulfur oil - most of which is imported - Con Ed was defenseless during recent oil price increases.

Of course, not everything at Con Ed has been the result of forces beyond the company's control. Officers, including Luce, have done things which almost justify the tag Johnny Carson likes to pin on them: "The Mickey Mouse Power Co."

Its rates, for instance, are stacked in favor of large and inefficient users of electricity, such as the World Trade Center, which was paying as little as 0.65 cents per kilowatt hour, while less fortunate commercial users paid 4.27 cents, and residential consumers, 5.53.

In 1974, for the first time in 89 years, the company decided to withhold its quarterly dividends, in a disastrous move which not only sent the price of its own stock plummeting but depressed the whole industry.

Probably as long as it exists, Con Ed will remain an object of derision, particularly for politicians who see in the utility's roughly 3 million customers a sympathetic chorus.

Also, as a consequence of the rate base concept written into New York's State Gas Commission in 1904, politicians have come to regard the utility as an easy and painless tax collector. A very large chunk of Con Ed's revenues go to state and local governments in taxes, including a city real estate levy that assesses generating equipment as real property.

The company's accommodations to the political establishments is not limited to taxes. Until recently, Tammany Hall and Albany used the utility's bureaucracy as a dumping ground for friends and relatives.

But Luce sayd all that is history. Management has been cleansed, dividends have been restored and increased (up to 50 cents as of January 1977) and profits are climbing. Unpaid bills are down to less than half of what they once were.

"Several power generation and distribution system records were set in 1976, and for the second consecutive year there were no systemwide voltage reductions," boasts Con Ed's 1976 annual report.