Virginia Electric & Power Co. and E.C. Ernst. Inc., an electrical construction firm, yesterday reported increased sales and profits. Communications Satellite Corp., operating under a federal order taht requires some revenues to be set aside, reported lower earnings compared with 1976.

Vepco, a Richmond-based utility that serves the industrial and populated sections of Virginia, reported second-quarter profits of $39.8 million (38 cents a share) compared with $33.1 million (33 cents) in the same period last year, as revenues increased to $298.5 million from $243.8 million.

For the first six months of 1977. Vepco has earned $33 million (81 cents a share) on revenues of $643.1 million compared with profits of $71.5 million (73 cents) and revenues of $515.8 million. The utility had 71 million shares outstanding on June 30 compared with 65.7 million a year earlier, which reduced the recent earnings on a per share basis.

E.C. Ernst, based in Washington, reported record profits for the year ended March 31 of $3.08 million (2.10 a share), up 25 per cent from $2.46 million (1.31) in the previous annual period. Contract volume also rose by 25 per cent to a record $137 million.

For the fourth quarter alone. Ernst earned $1 million (67 cents) on a volume of $41 million compared with $907.172 (60 cents) and revenues of $31 million. Chairman Edward P. Johnson said yesterday that the backlog of contracts on March 31 was $111 million, up 11 per cent from a year ago.

Communications Satellite Corp., also based here, reported second-quarter profits of $8.97 million (90 cents a share) compared with $10.85 million (1.08) in the similar 1976 period. Operating revenues rose to $39.8 million from $36.2 million.

The decline in year-to-year earnings resulted from a deduction of $15 million of global communications revenues (equal to 75 cents a share in earnings), under a Federal Communications Commission accounting order that look effect in June 1976.

The FCC ordered Comsat to cut substantially its rates and Comsat has appealed that decision in the U.S. Court of Appeals here. While waiting for a decision in court, Comsat is setting aside an amount of revenues equal to the rate reduction ordered by the FCC, in the event refunds are necessary.

Six-month Comsat profits, similarly affected by the FCC order, declined to $17.8 million ($1.78 a share) from $21.9 million ($2.19 while revenues rose to $78 million from $71 million.Directors of the firm voted a regular quarterly dividend of 25 cents a share on Sept. 12 to stockholders of record Aug. 12.

Rowe Furniture Corp. of Salem, Va., reported a loss of $415.000 for the second quarter ended May 31 compared with year-earlier profits of $125.000 (5 cents a share). Furniture shipments declined to $11.5 million from $12.8 million.

For the first six months of Rowe's fiscal year, the firm reported a loss of $196.000 vs. profits of $635.000 (28 cents) and shipments fell to $23.1 million from $25.6 million. Chairman Gerald M. Birnbach said the recent quarter's losses reflected expenses in a proxy fight for company control, which ended in compromise.

Atlantic Research Corp., of Alexandria, reported profits of $465.000 (97 cents a share) in the first half of 1977 compared with $151.000 in the same period last year. Sales rose to $15.9 million from $11.5 million.

Citizens Bank & Trust Co., of Riverdale, Md., reported first-half profits of $3.2 million (53.04 a share) compared with $3.3 million ($3.14 with fewer shares outstanding) a year earlier.