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Full text of "The Capitol sub-station at South Capitol and G Streets, Washington, D.C."

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Cmtl ire. 

I. Fiptcry. 

a. Location of station. 

B. Construction o^ station. 

C, Relative cost. 

II. Operation of the station. 

a. Equipment, 

B.. Ceneral discussion of operation. 

C. Signal operation. 

III. Sub-station testing. 

A. Preliminary tests without D.C, control 

and A.C, power. 

B. Tests with D.C. control but no A.C. power. 

C. Tests wit 1 ' D.C. control r nd A.C. power. 
IT. Summary. 

V. Illustrations an' Muenrints. 


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1. History. 

The Capitol Sub-Station at South Capitol and G. Streets is but one 
of the many of the out-of-doors Sub-btations that supply the power to the 
trolleys of the electrified Pennsylvania Hailroad. 

Location of the stations. 
The site chosen for this sub-station at South Capitol and G. Streets 
was the location of a portion of a canal twenty five years ago. It later became 
a part of a freight yard, and on July 7, 1934 the ground was broken and the 
construction of the station started. 

Construction of the station. 
Quoting the Inspector in charge of the construction, "I was handed 
a set of blue-prints, a level and a rod, a plumb-bob, and was given the location 
of the center line of the station, a definite angle ar.-' a bench-mark elevation, 
and was told to go to work." With this meagre equipment and info '-mat ion the 
construction was begun. 

The excavation of the dirt and the grading of the land was done 
entirely by laborers with picks and shovels, the inspector being; -unable to 
obtain the services of a steam shovel. The lab ore rp were rr.en from every 
Division of the Pennsylvania Railroad who had been on furlough prior to the 
beginning of the construction. 

The forms for the foundations for the steel work, the trans- 
former pits, the pocket for one of the transformers, pedestals for the 
circuit breakers and potheads , and the concrete columns were constructed by 
these inexperienced men. The concrete was poured from concrete trains, on 
tracks betide the construction site. 


,-ater drainage was a problem that ha- to he met and as fie station 
is nearing completion is still unsolved. Mo provision was mare for drainage 
except the grading in the original plans for the b tali on, and the necessary 
authority for the addition of the desired drainage has not "been obtained. 

The placing of t e equipment was the next phase of the construction. 
The transformers were placed upon their foundations by means of a large trailer 
and tracks leading from the South Capitol Street side of the atation, to their 
final position. difficulties were met in theplacinr of the steel because of 
the weather conditions, and the lack of ex-erience of the laborers. The 
switch-house is of a flat roof type constructed of a cinder base cement, 
reesvlting in a sturdy weather resisting building for the housing of the control 
equipment. The site is enclosed with a twelve foot wire fence. There are two 
entrances to the sub-station lot, and the fence is topped with several strands 
of barb wire. 

The wiring of the sub-station was done by experience? electricians, 
and by December 5, 1934 the 122 KV cable was given a direct current test. The 
station was placed in operation January 27, 1935, and will be entirely completed 
some time within the month of Hay 1935. 

Relative costs. 
The actual figures for the construct icn and equipment of the 
Capitol sub-station are unavailable, but an estimate base" 1 on the amount of 
special equipment contained in the station, places the entire cost close to 
one million dollars. As an illustration, the cost, of one transformer use 1 
for the reduction of the 132, 000 Volts to 12,000 Volts is around $40,000. 

The cost of labor was high because most of the contruction was 
by hand. 


With but these few features in mind one can realize the enormenus 
cost of euch £i substation as compared to a standard substation where the 
relative coat is around $300,000. 

2, Operation of the station. 
The Capitol sub-station is one of a series of substations used 
to step-down 132 KT to 12 KV for track distribution over and around the 
District of Columbia on the electrified Pennsylvania Railroad. 

The equipment. 
The Capitol Sub-station, because of its many special features, 
contains the equipment of a standard station and equipment for the signal 
power and its control. The equipment will be discussed in two sections - 
the equipment of a standard station, and the special equipment. Only the 
main elements of each section will b© presented* 

The main equipment for a standard station included the following; 
The main 132 KV step-down transformers, current, potential, and service 
transformers; circuit-breakers of various ty-es; over-current, high and 
low potential, time, and temperature relays; lightening arresters on the 
steel structure and a 120 foot lightning pole; motor operated switches iriven 
by a small direct current motor generator set, and by batteries in case of 
necessity; and the necessary controlling equipment located on the panel board. 

The special equipment includes the following: signal and power 
transformers; a 2300 volt alternating current motor generator set; controlling 
relays; and necessary breakers for safe operation of the signal power line. 

There are four of the 132 KT step-down transformers in the station. 
Three of these transformers were constructed by the "eneral Sleetric Company, 
the other by the Al lis -Chalmers Company. Both type? are oil Immersed, self- 
cooled transformers. 


The classification of the two t^nes Is as follows: 
General Electric type AUi^Chalmers_type_. 

Frequency 25 cycles Frequency 25 cycles 

Voltage rating 132,000/12,000 Voltage rating 132,000/12,000 
Temp. rating: Temp. rat in : 

at 45C0 KVA.a 45°C.rise above at 100% loa: , 45°C.riB« above 

outside temp. outside temp, 

at 6750 KVA.for 2 hrs a 60°C. at 150% load for 2 hrs a 60°C. 

rise above outside temp, above outside temp. 

at 13.50C KVA.for 5 rains. a 75°C at 300 % loa< for 5 mins.75°C. 

rise above outside temp, rise above outside temp. 

Impedence voltage, 4% Impedence voltage, 4.11 % 

Polarity, subtract ive Polarity, subtract ive 

Approximate weight to be lifted Approximate weight of core and 

when untanking 61000 lbs. coils, 67,000 lbs. 

Approximate weight of tank an" Approximate weight of case 

fittings 28000 lbs and fitting, 23,000 lbs. 

Approximate weight of 6,470 gal. Approximate weight of 5,470 

of #10 C. transiloil 48000 lbs gal.ell, 41,000 lbs. 

Total weight for outside Total weight for outdoor 

installation 137000 lbs installation 131,000 lbs. 

These transformers step- own the 132 EV.for use on the trolleys. 
The other transformers are emaller. The ei rrent transformers are 
used in connection with the relays to af^or" protection to the 132 EV. trans- 
formers and the signal motor generator set. 

The potential transformers are used to determine the volta e of 
the 12 KV'.bus, to operate the watt-hour meter on the switchboard, and to 
supply the voltage tc the relays, The service transformer supplies -?ower to 
the motor generator set for the operation of the disconnect switches, and 
supplies power for lighting purposes. 

The circuit breakers are of the oil-blast type. These breakers 
are constructed by the General Sleclric Company and are of triple- pole, 
oil-breaking construction with a high interrupting capacity , The essential 
features of these breakers are the following: 

No.l. ArelBg time iB very short, and in most cases less than 

one cycle. 
Ho. 2. Each phase of the circuit is isolated in a separate 


Ho. 3. There are two breaks in series in each phase, 

Ko.4, 2ach break is made in a separate cylindrical oil tank, 

constructed of seamless drawn steel, and equipped with oil-blast 
Ho. 5. Each oil tank is equipped with a separating chamber to prevent 

the ejection of any oil which may be carried up with the exhaust. 
Ho. 6. Opetation ie by a motor operating mechanism whic 1 is trip free 

at any point in the closing stroke, 
Ko,7. Jontrol circuits are insulated from main circuits. 

These circuit breakers are rated at 15,000 ani 23,000 volte, ani 
600 to 4,000 amperes . The oyer current, high and low potential, teimerature, 
and time relays are controlling devices i - se in protection o^ the station 

The single transformers are rate at 100 £V«.. , 25 cycle 
12,600/2300 - 440 volts and supplies the potential to the motor enorator set 
used for signal power production, The power transformer 1b rated at 75 KVA. , 
460/6900 volts, single-phase, 100 cycles. The large motor generator set 
consisting of a starting motor capable of 20 horsepower at 440 volts which 
starts an induction motor capable of 100 horsepower at 2300 volts. The 
induction motor is single-phase, has a frequency of 25 cycles, and drives an 
alternating current generator rated at 75 IOTA., single-phase, 440 volts, 
100 cycleB. The field of this generator is supplied by a small three KW. , 
125 volt exciter which is operated on direct current. 

The control of the sub-station may be either at the station or 
at the Virginia Avenue tower. The tower is equipped with a model switchboard 
containing sectional! sing switches and all controlling features that are found 
on the sub-station control board. 



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General d is cute ion of operation* 
Power to the Capitol £ub-Btation ie transmitted overhead from 
Safe Harbor,Maryland via Anacostia, D.C., at 132 KV., and is brought from 
Anacostia into the sub-station in underground Parkway oil-filled cables. 
The station is so connected that in case of a failure of the cable coming 
from Anacostia, the power can be fed from Potomac Yards, Virginia. 

The 132 KV., ie brought through potheads to a high voltage bus 
on top of a steel structure. The high voltage bus is divided into two 
sections, one section only being supplied power directly at one time. These 
sections are connected by a 12-21, air-break, horn-gap switch which has a gap 
of 47,5 inches from the horn to the bus ring. The 132 KV, step-down trans- 
formers are so connected to the high-voltage bus sections that there will be 
a transformer from each section supplying the low voltage 1? KV.bus regardless 
of which bus section is in operation. The 132 KV. is stepped -iown to 12 KV. 
in these transformer*, and passes from the secondary through an oil circuit- 
breaker to the low voltage bus on another steel structure. 

This low voltage 12 KV, bus is also divided into two sections 
which are connected by a disconnect switch around which is a BB. oil 
circuit breaker. The main trars formers are connected so that one from 
each section of the high voltage bus will supply one section of the low 
voltage bus. These high and low voltage connections are made so that in case 
of an emergency either section of the low voltage bus can be fed, and the 
power supplied to the trolleys. Taps are made from each section of the 
low volta L e bus through circuit breakers and pot- heads to supply the 
Potomac YardB sub- station, Union sub-station, and Landover sub-Btation 
with 12 KV. trolley power. Other taps are made off the 12 KV.bus to 
supply power to the service, potential, current, and signal transforfrmers. 



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The service transformers reduce the 12 KV. to 220 and 110 voltB 
for lighting purposes and power to the motor generator set which operate the 
disconnect switches in the various circuits. The potential transformers 
step-down thel2 KV. to 110 volt6 for the operation of the watt-hour meter 
on the switchboard, the operation of the various potential relays, and for 
determining the voltage on thel2 KV. hue. The signal bransformer Bteps the 
voltage down to 2300 and 440 volte for the operation of the si/nals on the 
electrified Pennsylvania Railroad in this area. 

Signal Operation. 

The special feature of Capitol Sub-station is that it contains 
equipment which supplies the power to signals for this area in the vicinity 
of the District of ColumMa. 

Eef erring to the sketch, the 12 KV. bus is tapped from both 
sections so that either can supply the power to the signal transformer. The 
voltage is carried through a circuit-breaker (52-0. C.) , through two current 
transformers and protecting relays on the switch-^anel board, into the signal 
transformer which is rated at 100 KVA. , 25-cycle, 12,600/2300 - 440 volte. 
The main secondary of the transformer steps the 12 KV. down to 2300 volts 
while the second secondary steps it down to 440 volts. Connections are made 
on the panel board through relays to the signal motor generator Bet. The 44C 
volts feeds a small 20 horsepower starting- motor which starts the 100 horsepower, 
single-phase, 25 cycle induction motor which is fed from the main secondary of 
the transformer. As the induction motor picks ut speed the starting motor 
automatically drops out. of the circuit. The induction motor drives a 75 KVA,, 
single-phase, 440 volt, 100 cycle alternating current generator which has its 
field separately excited by a small direct current three KIT., 125 Tolt -enerator. 
This exciter is fed by the service transformer through relays on the switchboard. 
As the power leaves the alternating current generator i + is fed 


through a power transformer rate J at 75 KVA, , 460/6900 volts, sin le-phaee ,106 
cycleB in which the voltage is boosted to 6600 volts. The power passes through 
a breaker and a ?.b JiVA. ,6600/lGO cycles trans former, and is transmitted to Landover 
at IOC cycles. 

3. .Sub-station testing. 
In preparing a major railroad electrification for service a considerable 
amount of careful testing ie required in the substations. This testing may be 
divided into three general groups as follows: 

A. - Preliminary teats without direct current control and alternating 

current power. 

B. - Tests made with direct current control but no alternating 

current power. 

C. - Tests made with D.C. control and alternating* current power. 
The tests included in each group will be listed, and one test from each 

group will be described. 

GEOUP A. Preliminary tests without direct current control 
and alternating current power. 

1. Current transformer polarity test, 

2. Primary and secondary winding check, 

3. Circuit breaker and transformer oil test. 

4. Transformer megger test. 

5. Power transformer tap changing device check, 

6. Manual operation of all switch equipment. 

7. Electrical interlocking check. 
e. Physical check of all relays. 

9. Setting of lightening arresters. 
The circuit breaker and transformer oil test is made before any of 
the oil-filled powsr transformers , transformer low Bide circuit breakers, and bus-tie 
breakers are energized to see if there will be any electrical breakdown la the oil. 



Samples are taken from each piece of equipment with extreme care and placed in 

clean dry bottles to protect the sample oil from dirt and moisture. The oil if 

tested in a test set consisting of a variable voltage transformer and two electrodes 

spaced axactly o.l inch apart in a porcelain cup. The cup is thoroughly cleaned 

and filled with the sample oil. The voltage is raised until the oil is broken 

down if possible. At least six sables of oil from each piece of apparatus are 

tested as above, the average break-down value to be not less than 25 KV. If the 

oil fails at a lower value it must be run through a filter press until its 

breakdown value is raised to the required amount. 

CftOUP B. Tests with direct current control but no 
alternating current power. 

1« Direct current energizing of relay and control board. 

2. Electrical control and indication of apparatus test. 

3. Electrical interlock test, 

4. Kanua.1 relay operation of apparatus test. 

After the miscellaneous preliminary tests have been made a 125 volt 

control battery should be connected to the combined control and relay boards 

for the direct current energizing test. The relay and control bus see behind the 

board are sectionalized by two pole knife switches. The sections should be energized 

one at a time in order to locate grounds if any exist. Two lights, one connected 

to negative bus and one to positive bus, having their other terminal connected 

together and through a push button to ground. When this button is pressed both 

lan^e shall light with equal intensity if there are no grounds on either bus. This 

test should be made as each bus section is energized. 

GBCiuf C . Tests with direct current control and 
alternating- current power. 

1. Energizing transmission test. 

2. Energizing power transformer test. 

3. Phase test between 132 KV. lines and 11 KV. buses. 


GRQUP C. { continued) 

4. Energizing entire Bub-station test, 

5, Short circuit tests with reduced voltage on cables 
between sub-stations. 

6. Eeduced voltage ground tests on high speed breakers. 

7, Eeduced voltage ground test on 11 KV. trolley buses. 

8. Reduced voltage test for back-up protection. 

9, Eeduced voltage test for transformer internal faults. 

10. Reduced voltage test for transmission line protection, 

11. Phasing and insulation test of catenary system. 
1?, Pull voltage ground tests on high speed breakers, 

13. Directional load test. 

14. ?ull voltage ground test on transmission lines. 

15. Full voltage short circuit tests on transmission lines 
and cable feeders. 

The energizing test on the entire substation is befur. 

after the transmission lines and substation has been entirely phased out, 

Ihe entire substation is energized up to the T-disconnect switches in the 

trolley feeders, care being taken that these switches are locked open and 

the trolley feeders on the catenary side of the switches are grounded. 

The substation should remain energized for several hours in order to allow 

all the equipment and bus set to "soak". This should show up any defective 


While the alternating current power 1b on all the equipment 

fed from the 50 EVA. service transformers should be tested to see if it 

operates properly. The switchboard in the switch house includes an 

alternating current power panel energized by the two service transformers 

through a double pole, double throw switch. The substation lighting 


should "be tried one circuit at a time. Thie should be done at night so it can 
be determined if the anparatus is illuminated properly and ec as to focus the 
floodlights. The oil purifying equipment, including filter .iress, oven, etc., 
should be operated for a few minutes to make sure fehat all electrical connections 
are correct. 1 eaters and all other equipment operated from the 110-200 volt 
power panel should also be tested as abcve. Also during thie test the potential 
devices connected to the 132 KV. bushings on the high side of the 4500 KVA. 
transformers are calibrated. 


4. Suanary, 

Jh« Capitol Substation plays the roe of a cog in the machinery 
for the supply of power to the electrified Pennsylvania Railroad. It is 
ahle to perform the duties of a standard station in stepping down the 132,000 
volts, used in the transmissin of the power, to the deBired voltage of 
12,000 volts for use In the trolleys. In addition to this, the station 
contains equipment used in lowering the 12,000 volt - 25 cyle power to 
6,600 volts - 100 cycles for the operation of the signals. 

The lighting power and the power for the operation o* the 
controlling mechanism of the station are tapped off the 12 EV.- low side hue 
and stepped down through transformers for use in thp station itself, 

The intricate equipment o^ the station nmst remain in 
workinr order for it to he of any service to t'-^e Pennsylvania Eallroad, 
therefore, at certain intervals o'' tine tests are raada on each piece of 
apparatus. The numerous substation tests are classifie undsr three grouns , 
and are as follows: Preliminary tests without E.C, control an" A.J, power; 
teete with D.C. control but no A.C, power; tests with D.C. control and A.C, 
power. Through these teste the proper functioning of the station equipment 
is ineured for the correct maintenance of the station, 

Thus the Capitol substation at South Capitol and G-. Streets, 
Washington , E.C., satisfactorily functions as a oart. of the enormeous 
electrification project of the Pennsylvania Railroad. 



Bibliography ,.... 


Mr. C.W.Bogan 

Mr. J.H.Mc.!:eil 

Mr. C , Erne ry 

Mr, F. Blum 

Mr, L.J. ilodgins 

Inspector in charge of t'^e construction of the Capitol 

Foreman of Construction. 

Maintainer cf --he Capitol sub-station. 

Maintained of the Lan&over sub-station. 

Professor cf Electrical Engineering, university 
of Maryland. 

General Electric Company Pamphlets on Circuit breakers and Transformers. 
Pennsylvania Hailrcad Co. Instructions for sub-station testing. 

Illustrations and blue prints. 

One of electric locomotives in operation 
on Pennsylvania Railroad. 

Left to right, Ur. tmi'h, Cable 7oremar; ?'.r. McNeill, 
Foreman of Construction; Mr. Bogan, Inspector in Charge 
of cons traction. 

Cable gang. 



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Early stages of construction. 

Forms for t'».e pocket into which a transformer 
is to he placed. 

A Tiew of finished pocket and crib wall. 

Si~e and front views of first column -,o "be 

Concrete train at work, pour in- foundations. 

Two of transformers in position with the 
crifc wall in background. 

12 KV. "bus section under cons true 1 - ion. 

Kight views of Lhe construction 
nearirijj complation. 

another nit~ht view of construction. 

Looking skyward of inside of one 
of columns. 


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Front and Bide views of completed station. 

Transporting a transformer. 

Placing a bushing in a transformer. Closeup of bushing 

2. Rrd Allis Chalmers 132 KY.etepdown transformers, in position. 


Top of steel tower on 13? KV.side. 

Pothead for incoming IS? KY. Air-Freak horn -gap switch structure. 




voltage bus. showing circuit "breakers 


k JKA..high speed G.E, air-breaker lgcate^ at Landover, 

Signal transformer and 52- 



Ligh&ng pole, 120 ft. 

Exterior view switch house. 

Cables beTn^irawi into switchhouse hefore swltc 1 board installed. 

Front view of control board. 

near view of control board showing wiring. 

View of some of relaye on panel "board, 

Interior of battery room. 

Signal motor generator set, 

Circuit breaker No. ?52-C in the signal circuit. 

Upper: Scene at the laying of 
the first submarine power feeder 
across the Potomac River for elec- 
trification of the Pennsylvania's 
Potomac Yards in Virginia, a $250,- 
000 project to be completed soon. 
The barges travel about 10 feet per 
minute, dropping the triple series 
of cables as they crawl along. The 
center of the river was reached at 
noon today. Similar cables will be 
laid upstream on the north side of 
the river, beginning next week. 

Lower: Each of three drums of 
lead encased wires, weighing 54 
tons apiece and costing $10,000 
each, drop the 11,000-volt concen- 
tric power cables into trenches 16 
feet wide and 10 to 18 feet below 
the bed of the river. They run 
from the Capital Power Substation 
to the FotomRc Switching 
on the south Bide of the 
Two of the feeder lines 
power, the third is a "spare 

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