was necessary to establish liability prior to energizing the transformer, a fourth transformer was immediately assembled and substituted in the K1A bank in order not to delay the on-line schedule of the first generator.

Responsibility was ultimately placed with the construction contractor, and it was proposed that the transformer could be placed in service without untanking to locate the missing lockwasher if the contractor would extend the manufacturer's warranty for 5 years and bear the costs of an extensive combustible gas analysis program. The contractor's decision to accept this proposal was made on January 12, 1965, and the transformer was placed in the K3A bank and energized in conjunction with unit 4 start-up procedure on February 8, 1965. During the first 3 years of operation, no difficulties attributable to the lockwasher appeared.

Assembly of all Pennsylvania transformers was completed December 8, 1964; however, the last unit was not energized until February 1966. All insulating oil for transformers was degasified by vacuum treating as it was pumped into the transformers. With this method, dielectric strengths approaching 40 kilovolts were obtained.

8,000-kv.-a.

239. SHUNT REACTORS. Twelve shunt reactors (fig. 292) were furnished by General Electric Co. under invitation No. DS-5828 for installation on the 13.8-kilovolt bus at transformer K7A. All of the reactors were shipped in the latter part of November 1963, scheduled to arrive at the site in time to meet the installation schedule. However, six reactors sustained major shipping damage in route and were returned to the factory without having reached their destination. The damaged units were beyond repair and were scrapped. The replacements were not shipped from the factory until June 1964.

The services of an erecting engineer, who was already at the site for installation of other equipment at Glen Canyon, were utilized for the installation of all reactors. The first six reactors were installed by the completion contractor on the unit 7 side of transformer K7A and connected to the isolated phase bus. Shortly after the units were energized, excessive temperature rises were noted in the vicinity of the installation. Extensive cracking was observed in the concrete deck supporting the reactors. The reactors were removed from service on September 7, 1964, and the supplier was requested to proceed at once with modifications to limit the temperature rise.

Installation of the six reactors on the unit 8 side of transformer K7A was delayed until an aluminum

Figure 292.-Closeup view of two shunt reactors. P557-420-9943, July 13, 1964.

shield, 8 feet in diameter and 3/8 inch thick, could be fabricated and placed under the concrete base of the reactor. The assembly was completed and test energized on October 29, 1964. Extensive checks of the temperature rise of the supporting concrete and reinforcing steel with the reactor bank energized, showed that the addition of the circular shields was ineffective. The supplier modified the shielding by filling in the gaps and extending the shield beyond the reactors. Further temperature rise measurements indicated that while the rate of increase had slowed, the total rise at ultimate use would still be beyond specification limits. However, operational requirements were such that the lower half of the reactor banks could be disconnected; and since the temperature rise with this method of operation was not excessive, no further modifications were required.

Extensive tests of the area under the unit 7 side reactor bank were conducted to determine the extent of structural damage. Analysis of test cores by the Bureau's Denver laboratory and the space-frame analysis by the designers indicated no structural defects. Therefore, only replacement of the deck cover slab was required of the supplier. This was necessary in

control

boards (fig. 200) were fabricated by Westinghouse Electric Corp. under invita

tion No. DS-5751

and were transported

by motor freight. Individual panels were complete

with meters, relays, switches, and internal switchboard wiring. Shipped in the latter part of 1963, the boards were installed in the powerplant control room early in 1964 (fig. 293). Interpanel switchboard wiring and some minor modifications were done at the site by Westinghouse.

Interboard control cable was furnished, installed, and terminated by Anderson Electric Co., subcontractor for electrical work under specifications No. DC-5750. Internal board wiring and cable connections were checked and the relays and meters furnished with the boards were calibrated and set.

included the unit phase balance

relays,

device 46,

and the overfre

quency relays 181.

With the expedited program for early service for units 1 and design

2.

representa

tives from

the Denver office were at Glen Canyon to make desired corrections to the control scheme design and wiring details. Temporary connections made at this time included the 230-kilovolt east and west bus overvoltage protection and connection of the reactor bank to the low side of transformer K7A.

Soon after initial operation of units 1 and 2, work began for temporary operation of the Glen Canyon-Pinnacle Peak line No. 1 at 345 kilovolts. This required changes in current transformer connections of transformer K7A, changes in differential and breaker failure relay tripping, and other related changes. The

Pinnacle-Peak line No. 1 controls and relays were also placed in operation and functionally checked at this time.

The need for unit dropping became apparent early in system operation, and a temporary unit dropping scheme was designed. Relays were mounted on a plywood panel which was installed at CCA 13 utilizing spare circuit breakers at the rear of the unit control panels. Numerous modifications of the scheme have been made since that time due to changing conditions and the need for improvements.

New boards for the permanent relay system for the Glen Canyon-Flagstaff lines No. 1 and 2 were purchased under invitation No. DS-6227 from Keystone Electrical Manufacturing Co. The spare line relay panel on board CCC was connected to provide relay protection on the Glen Canyon-Flagstaff line No. 1 during the installation of these new boards. Installed by the completion contractor under a change order, substantial additions of control switches, meters, indication, wiring and cable were involved.

Addition of 69-kilovolt lines required additions and modifications of the control boards. The work was performed by the completion contractor under a change order. New indicating meters and control switches were installed on spare panels of the CCB board. Relays in the CCD board, originally provided for future 138-kilovolt lines, were used. The added control equipment was furnished by the Government under minor purchase orders.

241. STATION-SERVICE POWER SYSTEM. The primary 4,160-volt intermediate voltage switchgear, the secondary 440-volt unit substations, and the lighting distribution unit substations required for the station-service power system were furnished by Allis-Chalmers Manufacturing Co. under invitation No. DS-5732. This equipment was shipped to the jobsite during March, April, and May of 1963.

Installation of the equipment was started in October 1963, and continued as surfacing for the floors of the powerplant was completed. Assembly of the switchgear, the transformers, and disconnects by the completion contractor was performed under the technical supervision of the manufacturer's erecting engineer. Final checkout of the operational functions of the equipment was completed by the erecting engineer and Bureau test personnel in June 1964. The only significant difficulty encountered in assembly involved mismatch of rigid bus connections between components, which was corrected by factory

refabrication of the bus without delay of installation work.

The primary power supply for the station-service system is provided by three 3,750-kv.-a. power transformers furnished by Westinghouse Electric Corp. under invitation No. DS-5828, and two 500-kv.-a. induction voltage regulators, furnished by General Electric Co. under another schedule on invitation No. DS-5828. The voltage regulators arrived at the railhead at Flagstaff, Ariz., on September 18, 1963. They were hauled to the powerplant by the completion contractor and set in position on the transformer deck during the following week. The three power transformers furnished by Westinghouse arrived on August 7, 1963, and were hauled to the transformer deck by the completion contractor shortly thereafter.

The interconnecting nonsegregated phase bus for the regulators, transformers, and 4,160-volt switchgear was also furnished by Westinghouse under invitation No. DS-5828. This equipment was received at the Flagstaff railhead on January 10, 1964, and installation was accomplished in early February. Other major items of station-service equipment included the unit auxiliary powerboards, air-conditioning powerboards, and miscellaneous power distribution panel boards, which were furnished by Federal Pacific Electric Co. under invitation No. DS-5787. The major portion of this equipment arrived at the jobsite in September 1963.

Installation of the powerboards by the completion contractor was scheduled to coincide with the required in-service dates of the major unit equipment. As installation progressed, equipment deficiencies appeared which required field modification. Some deficiencies were corrected by the completion contractor as required to place equipment in service and other corrections were arranged for in advance by the manufacturer.

The powerplant station-service system was energized from a temporary 12-kilovolt source on July 15, 1964, after successful high-potential testing of the equipment. This temporary source was used for all plant auxiliaries until December 30, 1964, at which time the transfer was made to the permanent connections on the unit 3 and 4 isolated phase bus. By this time the 25-kilovolt cable from the switchyard to the powerplant had been installed by the completion contractor under specifications No. DC-5750 and was available as a standby power source.

242. COMMUNICATIONS. The automatic switchboard and control room operator's turret were

furnished and installed by Stromberg-Carlson under invitation No. DS-5976. The dial telephones, extension bells and the code call relays and signaling devices were also furnished by Stromberg-Carlson and were installed under a change order by the completion contractor.

Installation of the automatic switching equipment was started on February 14, 1964, and was completed on March 6, 1964. As negotiations with the completion contractor for installation of extension equipment and interconnecting wiring were not complete, telephones were initially installed on a temporary basis at critical key locations by Government forces. Service from these lines was discontinued as the permanent installations were made. Interconnection to an outside line was first made by tielines to the attended switchboard at the administration building in Page. When the offices in the powerplant were occupied, a new Bell System switchboard was installed. Interface equipment was also provided to allow direct out-dialing for emergency and power dispatching purposes. An additional trunk adapter was purchased and installed by Government forces to allow for increased direct dial access to the Colorado River storage project microwave system.

A terminal cabinet and a 100-pair cable were installed by Mountain States Telephone Co. in the powerplant telephone equipment room. The cable was routed through the control cable tunnel to telephone company terminal facilities near the switchyard.

For the early stages of operation of the powerplant, interconnections for communications and metering

were made to the Arizona Public Service Co. microwave system by way of a Government-furnished 25-pair cable. This cable was installed from the control room area to a terminal pole near the 69-kilovolt area of the switchyard by the completion contractor on a change order. Terminations were made in the powerplant at a telemetering equipment rack furnished by Arizona Public Service.

The permanent terminal cabinet and 100-pair cable from the Colorado River Storage project microwave terminal facilities were furnished and installed by Stromberg-Carlson under specifications No. DC-5853. Digital telemetering transmitters, load thermoverters, and associated tone transmitters and receivers were furnished by General Electric Co. under invitation No. DS-5921 and were installed and connected by the completion contractor. Transfer trip relaying tone transmitters and receivers, furnished as a part of the microwave system, were also installed and connected by the completion contractor.

243. BATTERY CHARGERS. Two static-rectifier type battery chargers were furnished by Federated Engineering Development Corp. under schedule No. 3 of invitation No. DS-5787. Shipment of the chargers was greatly delayed by priority work in the supplier's plant. The late delivery had no adverse affect since procurement of the station battery was rescheduled to coincide with the delayed delivery. The chargers were received and installed in late February 1964, and the first unit was placed in service in May.