HISTORY AND DEVELOPMEl^IT of the BUZZARD POINT STATION P0T01.IAC ELECTRIC POWER COllPANY ■am CHARLES F. JANES Presented As Requirement For Initiation Maryland Beta Chapter Tau Beta Pi Association r HISTORY AND DEVELOPMENT OF THE BUZZARD POINT STATION POTOLIAC ELECTRIC POWER COMPANY SmCLIARY Since t896 Washington has teen served "bj the Potomac Electric Power Company, which bought out all of Its competi- tors and built the present plant at Banning in T906. This initial installation of 25,000kw. was added to, from tinie to time, to keep up with the growing demand for power until it was developed to the greatest extent, to which it could be operated economically in 193T, when it had a total capacity of 208,000 kw. In March T933, the 230,000 volt line connect- ing Washington with the Safe Harbor hydro-plant on the Sus- quehanna was put into service, InBuring Washington a reliable supply of povrer under all circumstances. To keep pp with the demand, plans were drawn up for a new plant, which it was fin- ally decided to build at Buszard Point in Southwest Washington. This plant was opened in November 1933 as a base load station with a capacity of 35,000 kw. Because of its modem design and the fact that it operates as a base load station. Buzzard Point operates at a much higher efficiency than any other unit of the Potomac Electric Power Company. HISTORY AND DE\^ELOPMEFT OF THE PUZ2ARD POINT STATION POT CMC ELECTRIC POWER COMPANY BACKQ-RQUND Prom the' Initial Installation at Bennlng In t906 of 5-5|000 kw. , vertical type tiirbine- generators there have "been frequent additions and Improvements of equipment with subse- quent removal of otsolete units, until the addition of a new 30,000 kw. imit in 1931 completed the economic development of this station. The total capacity of Bennlng was now 208,000 kw. which, Bincb the removal of the old plant at I4th and B Streets was the total source of power for the District of Columbia and vicinity. With an eye toward improving the reliability as well as the quantity of service, p modern 230,000 volt transmission line was built to connect with, the line from Baltimore to the Safe Harbor hyrdo-plant on the Susquehanna river in March 1933» It was realized that the Banning plant was subject to river conditions, as happened on March 2, 1914 vfhen it was forced to shut down bacauee an extra low tide left it without adequate condensing water; and again, on August 23, 1933 it was drowned out by flood, end the new inter- connection with Safe Harbor showed its worth. A maximum load of 60,000 kw. can be taken from Safe Harbor or sent to Baltimore in case of lov; water in the Susquehanna. As early as January 1931 plans were considered for "building a new steam plant to operate in conjunction with -O. Bermlng. The site for the new plant was considered very care- fully. The number of possible. site a finally came down to three: Siesboro Point on the south side of the Anacoetla river, site of the old wartime steel plant; some point on the Virginia side of the Potomac above Alexandria; and Buzzard Point on the north side of the Anacostla river, near the Army Yfar College. Objec- tions to the first tv;o were that cables would have to be laid across the river to the main load centers, and that they are farther from these load centers- Other advantages of Buzzard Point arej an ample sup- ply of condensing water is available; coal or other fuel can be brought by rail or water; and the area is zoned for indus- trial purpoaea. The fact that Buzzard Point was in line for future development as a park called for careful consideration of architectural design. The deai^ called for an initial installation of one 35 1 000 kw, unit and two boiler units, with space for another similar unit, the tv/o to be operated from separate boilers. Construction was sto,rted late in 1932 and the sta- tion put In operation as a base load station in conjunction with Benning and Safe Harbor on November T6, 1933* The total cost of the plant approximated ^5,000,000. The ultimate development of the site will Include four more 50,000 kw. generators for a total capacity of 270,000 kw. 1 '3- FSATURES OF THE STATION The arrangement of the boiler operating room and tur- bine room is such that the operators of one are easily accessible to the other. The boiler units are Bab cock and Wilcox single pass. Ions crossdrum 72 in. by 35 ft. 6 in. t.ype designed to bum a variety of coals, fuel oil or natural gas. Tfest Virginia coal Is used at present. Boiler pressure of 650 lb. and temperature at the tiorblne throttle of 835 deg.F. allow maximum efficiency T^ith a great degree of reliability. A simple regenerative cycle with three stage bleeding for feed water heating is used. Because of the probability of rapid fluctuation in load when naming a steam station in parallel with a hydro- sta- tion, the boilers were designed to give maximum "pick up" ability from low load conditions. Due to its proxlnilty to the many public "buildinss of the Mall, It was extremely important to eliminate smoke ctodi4 tions. For this purpose the stack is provided with a Cottrell eleotro-statlc precipitator in addition to comolete automatic combustion control. The boilers are each provided with two Riley mills and six burners. The present capacity of the boilers is 375»- 000 lb. of steam per hour, representing nearly t2,000 boiler horse power. The boilers are completely water cooled and equip- ped with a slag screen Just above the burners, composed of stag- gered tubes covered with refractory material, which causes the slag to run down and drip off Into the pit. The burners are fired downward so that the flame impinges on the slag at the -4- bottom causing the larger particles to be thrown off. The superheater is arranged in two sect lone with a desuperheater between, to control the temperature of the steam as It leaves the boiler. The turbine is a single cylinder, eighteen stage General Electric unit rated at 35,000 kw. at t,800 r.p.m. It Is set crosswise of the turbine room over a 30,000 sq.ft. Inger- soll-Rand condenser of the single- pass, two- compartment type. Bleeding for feed water heating Is done from the 7th, Ttth and I4th stages. The heaters are Foster-'«Yheeler direct contact type requiring a pump for each heater. The generating unit Is a General Electric unit rated at 38,888 kva. at 90^ power factor, 60 cycles, T3,800i, volts. The exciter unit consists of direct connected main and pilot exciters, A spare motor driven exciter of 200 kw. capacity is installed for use in emergency. The generator is air coaled using river water as the cooling medium. The lubrication system is very Interesting. With the use of high temperature steam the danger of fire from leaking oil became increasingly great. There have been several disas- trous fires due to this cause. With this in mind the designers of Buzzard Point incorporated a system whereby much danger is eliminated. All high pressure oil lines are enclosed inside low pressure return lines, thereby greatly reducing the danger of leakage. All the oil pumping equipment is located in a small fireproof room under the turbine itself. It is protected by a Lux carbto dioxide automatic extinguishing system and is com- -5- pletely enclosed "by Itself. There Is a separate room for oil storage, cleaning and filtering, which is protected by a steam- smothering system. The station auxiliaries are all driven by electric motors with the exception of one feed water pump, which is driven by a 700 horse power, single stage non- condens Ing turbine for use in emergency. This turbine is capable of gaining full speed from cold start in 30 seconds. The three feed pumps are seven stage centrifugal ptjmps each capable of handling hot vmter s.t 357 deg.F. at the rate of 800 gallons per minute. Since ultimately each boiler will operate a single turbine all the auxiliaries are grouped separately. A 4,000 kva. 13,800/2,300 volt, three phase transformer supplies the auxilia- ries of each main unit. All except the smaller motors and the ooal handling motors are 2,300 volt units, the others being 440 volts. The forced draft fa.ns are run by constant speed squirrel cage motors, speed control of the fans being done by hydraulic couplings. These couplings give wide range control with high efficiency. The speed Is controlled by changing the oil level in the coupling. The electrical equipment Is concentrated at one end of the building. The top floor houses the switch-board room , in which the main switch-board, automatic voltage control unit and station battery charging set are located. The switch- board is of the bench type with vertical back panel. The various indicating instruments and control switches are located here. In back of the main switch-board on a separate panel are the various relays and recording instruments. Located In a glass enclosed room off -6- the main switch- 'board room le the automatic voltage regulator equipment, which is of the FA-4 type. The battery charglns e- qulpment is at one side of the control room , separated "by an iron cage • The two main 13»800 volt busses occupy the fourth floor of the electrical bay. They are enclosed in reinforced concrete structures, as are the oil circuit breakers and dis- connect switches located on the third and fifth floors. These oil circuit breakers are G-eneral Electric imits rated at t,500,- 000 kva rupturing capacity and have sji arc-ruptiaring time of 8 cycles compared to e 60 cycle timing wave. The disconnects are all of the remote mutual gang operated except the H tie disconnects which are motor gang, operated and controlled from the main switch- "board. On the second floor are the feeder re- actors, rated at 5%, On the first floor are the out-going feed- er disconnects and potheads, and the cable test bus. The station service control swltch/feoard is located between the turbine room and the boiler- operating room. From it are controlled the auxilliarles of the plant. Buzzard Point is tied in with Benning by a J3tv tie- line and with Takoma by another 53 Irv line thro-ugh SUB- 13, lo- cated at 135th and Harvard streets. Six 13,800 volt feeders connect with SUB- 16 in the downtown area, direct from the sta- tion busses. Another 13,800 volt serves the Bureau of Engrav- ing and Printing. The 13,800 volt feeders are of the three con- ductor, 350,000 circular mil type H cables. The transformer system for the 33 kv tie- lines consists of three 20,000 kva -7- transformers, two of vrhich are phase changers. Because of the danger of the load being dropped In case of a 3-phase fault in the "busses of one of the substations these busses were split at SUB- 13, SUB-T6, and SUB-5, Buzzard Point feeds both parts of the busses at SUB- 13 and SUB- 16 with separate cables therefore Insuring continuance of service in case of a fault. SUBS- 13 and 5 connect with Takoma and thence to Safe Harbor, therefore It Is important that they be free from disturbance. SUB-16 is Important because it serves the main business district of the city as well as the G-ovemment buildings of the Mall. 20,000 kva, 13, 800/33,000 volt transformers at Buzzard Point Plant The archetecture of the building is simple and pro- mises not to mar the beauty of ejny future development at Buzzard -s- Point. The 90 ft. building looks somewhat modernistic with its high windows, square comers and octagonal stack, which Is 180 ft. high. The construction is of steel, "brick and concrete "block and is finished In a dull white shade. The station was designed and "built by Stone and Webster Engineering Corporation in co- operation with Potomac Electric Power Company officials and en- gineers . OPERATION OF THE PLAMT Since Buzzard Point Station has been In operation it has shown very high efficiency due both to its careful design and to the fact that it Is operated as a base load station. The great Increase of efficiency over the older units at Bennlng is shown by the accompanying chart. The best efficiency of the old vertical 5,000 kw. units at Bennlng was about 2.05 Ihs. of coal per kwh. while Buzzard averaged for the year 193^».888 lbs. per kwh, ajid in 1935.. B81 IT^s. per kwh. Following are a few statistics for these years: 193^ 1935 Gross generation 202,267,000 222,886,000 Station service 11,266,700 11,740,900 Net generation 191,000,300 211,145,100 Hours of operation 7|746 7* 515 Coal burned (lbs.) 169,782,500 186,628,100 BTU/lbs. coal 14,305 14,195 Lbs. coal/kwh. .888 .881 Overall boiler efficiency 84,28 85.7 -9- It is Interesting to note how the efficiency goes up as the steam pressiire Increases. The older imlts were operated at 200 Its, and then Improvements of design made It possible to operate safely at 400 lbs. which led to greater economy. At present the highest pressure, with Its accompanying high tem- peratxjLre, that can be used safely with the metal available is around 65O lbs,, which is that used at Buzzard Point. Other contributing factors to the high efficiency of the station are use of pulverized coal fuel with Its ease of combustion control, and the use of an air preheater and three stage bleeding for feed water heating. Buzzard Point Plant, as a whole strikes me as being a well designed plant from the standpoint of ease of operation and efficiency. Very few men are needed to tend the plant in normal operation. Probably the near future will see the addition of another 35,000 lew generator which can be operated almost as easily as the present one. The Electrical World — December 50, 1933. The T7ashlnston Star — 1933 The Washington Public Library — 'ffashingtonlana Div. Potomac Electric Power Company Engineers: Mr, W. J. Lank — Assistant chief engineer Mr. R. B, Kellogg — Plant engineer. Buzzard Point Mr. C. E. Miller — Test engineer, " **. Mr. H. B. Pollack— Switch-board operator, '* " Ifr. J. W. Thomas — Watch engineer, " " Mr. C. B, Tyson Jr. -- Plant clerk. 1 Potomac Electric Power Co. Electrical Engineer's Office Subject r "^ k G-eneral view of the plant from the south-west. F ^'L. A view of the front of the "building in which the office and lobby are located. The plant fronts on the Ana cost la River. 'H y ii }*K«««*W*5#%™W5«*',*a'J -JWja™'*-^«*.-^v-jrj mwjrjfjri^j'.fr rtr4nKtV^^j*'^*»-j*jtjt'>A*» VIKKAC j| The two 13,800/2300 volt Btation service transformers. I Plan and croBS-seetlon of Buz,2,ard Point Station.