Residential elelctric bills jumped 12.8 percent from December, 1976 to March, 1978 and business power bills soared 19.1 percent during that period, a survey of the nation's 24 largest electric utilities shows.

The increases were even greater at Virginia Electric & Power Co., which provided comparable figures to The Washington Post.

Vepco reported a 14.2 percent nincrease in residential charges and a 24 percent increase in business rates.

Pepco said its residential charges were up 14.6 percent and business charges up 23.7 percent.

The survey is made annually by National utility Service Inc., a New York energy cost consulting company.

"The survey reveals that despite (consumer) protests, electric rate increases are still being granted in substantial amounts and with greater frequency than ever before," said Sarkis Soultanian, excutives vi ce president of National Utility Service.

The sharpest increase two dozen utilities were at Union Electric Co. in St. Louis, where residential rates jumped 51 percent and business charges 76 percent. Pacific Gas & Electric Corp, SanFrancisco raised its business charges 74.5 percent and residential bills by nearly 39 mpercent during the 15 months.

The California drought cut off the water power Pacific's hydorelectric plants and the coal strike forced Union Electric to switch to costlier fuels, explained Soultanian.

The greater increases in business electric bills found by trhe survey are narrowing the traditional gap between commercial and residential electric rates, but residential customers still pay about 41 percent more per kilowatt hour than large business customers. A year ago the difference was 50 percent.

Soultanian sais the change "indicates the degree to which state public service commisions have appeased consumer lobby groups."

Utility activists have contended the lower rates for big utility customers are not justified by lower costs in serving big customers. They have also argued that charging lower rates for large users of power does not encourage customers to reduce their energy consumption.