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HomeMy WebLinkAbout1996-03-18 City CouncilCity of Palo Alto City Manager’s Repor TO:THE HONORABLECITY COUNCIL 9 FROM:CITY MANAGER DEPARTMENT:UTILITIES DATE: SUBJECT: MARCH 18, 1996 CMR:164:96 Approval of Budget Amendment Ordinance for Colorado Substation 60 kV Bus Tie Circuit Breaker Installation Project REOUEST This staff report requests the City Council to approve a Budget Amendment Ordinance (BAO) to increase the Electric Fund, Colorado Substation Bus Tie Circuit Breaker Project, Capital Improvement Program (CIP-9509) in the amount of $100,000. These additional funds are required to cover the costs of unanticipated structural and electrical design changes. RECOMMENDATIONS Staff recommends that Council approve a Budget Amendment Ordinance in the amount of $100,000, to be taken from the Electric System Improvement Reserve, to fund the structural and electrical changes required to complete the Colorado Bus Tie Circuit Breaker Project. POLICY IMPLICATIONS The additional funding does not represent any change to existing policy. CMR:164:96 Page 1 of 4 EXECUTIVE SUMMARY PROJECT DESCRIPTION The Colorado 60 kV Bus Tie Circuit Breaker Installation Project (CIP-9509) was started in FY 1994-95 to upgrade the Colorado Power Station to allow faster service restoration, greater maintenance flexibility, and increased system reliability on the City’s electrical transmission system. The operation and maintenance of the Colorado Power Station is critical to the service of customers within the City, as it is the only supply of power. Bus ties are installed to tie the main bus to the secondary bus. The proposed tie at the Colorado Power Station would be used to interconnect the main and secondary buses, in the event of an emergency, or during routine maintenance of substation equipment. This tie breaker is being added in accordance with the ultimate design plan for the Colorado Power Station developed by R.W. Beck Consultants in 1972. The project was designed by staff, and installation is ongoing by the City’s substation crew. At the present time, major structural steel fabrication work and the new foundations have been installed by contractors; and 50 percent of the work associated with the physical installation of the 60 kV tie breaker has been completed. The remainder of the construction is scheduled to finish within the current fiscal year. REASONS FOR INCREASED COST There were several design changes that increased the design time and the cost of the installation of the Colorado Tie Circuit Breaker. The design changes occurred in the following three areas: structural changes to accommodate the specified 60 kV breaker, additional seismic restraint requirements for the 60 kV bus, and electrical relaying and protection design changes required for the installation of new solid state relays to provide a more flexible substation operating scheme. When this project was estimated, it was anticipated that the existing foundations could be used for the new breaker installation. After the initial design work was completed, it was discovered that the existing foundations and bus support design would have to be modified to accept the specified circuit breaker. This modification for additional concrete foundations increased the cost by $20,000. CMR:164:96 Page 2 of 4 This modification occurred because the Colorado Power Station was originally designed to accommodate 60 kV oil type circuit breakers. In the intervening years since the original design, breaker technology has changed dramatically. Breakers now use an insulating gas (SF6) for insulation instead of oil. The use of gas as the insulating medium in 60 kV breakers has caused manufacturers to change the physical shape and size of the breaker and thus changed the foundation design requirements. In addition to the 60 kV breaker specification, the seismic requirements have also changed since the original substation design. Post earthquake analysis at substations has shown an increased need for seismic restraint. These additional seismic requirements caused staff to change the 60 kV buswork design by increasing the number of bus supports. This added $32,000 to the cost, including installation. The last unanticipated cost involved the increased design time for relay specification and for a flexible substation operating scheme. In the past, misoperation of circuit breakers have occurred on the City’s electrical system due to inadequate design of solid state relays. Staff undertook an investigation into the adequacy of different manufacturers relays to reduce the possibility of similar events occurring in the future. In addition to the relay investigation, staff designed a new control scheme to take full advantage of the bus tie circuit breakers. These changes increased the design and installation cost by $44,000. A revised estimate of this project has been prepared based on these project changes. Staff now estimates the total cost to be $250,000: The initial CIP budget estimate of $150,000 is insufficient to complete this project, given the necessary changes to the original scope. Due to the importance of the Colorado substation as the only source for the City’s electric system, staff would have recommended implementation of the project even at the revised cost of $250,000. FISCAL IMPACT The attached BAO requests an additional $100,000 be appropriated from the Electric Fund Reserve and added to the original CIP, to cover increased project costs due to the structural and electrical design changes. There are sufficient funds in the Electric Fund Reserves to cover this request. CMR:164:96 Page 3 of 4 ENVIRONMENTAL ASSESSMENT Approval of the BAO does not constitute a project under the California Environmental Quality Act therefore no further review is necessary. ATTACHMENTS Budget Amendment Ordinance Prepared by:, Tomm Marshall, Electric Engineering Manager DEPARTMENT HEAD APPROVAL; //~ EDW~,D J. ~ZEK Director of Utilities CITY MANAGER APPROVAL; ~ FLEMING Ci~ Manager CMR:164:96 Page 4 of 4 ORDINANCE NO. ORDINANCE OF THE COUNCIL OF THE CITY OF PALO ALTO AMENDING THE BUDGET FOR THE FISCAL YEAR 1995-96 TO PROVIDE AN ADDITIONAL APPROPRIATION FOR CAPITAL IMPROVEMENT PROGRAM (CIP)PROJECT NO. 9509, ~60KV BUS TIE BREAKER INSTALLATION" WHEREAS, pursuant to the provisions of Section 12 of Article III of the Charter of the City of Palo Alto, the Council on June 19, 1995 did adopt a budget for fiscal year 1995-96; and WHEREAS, on June 20, 1994, Council approved $150,000 in funding for CIP Project No. 9509, "60kV Bus Tie Breaker Installation"; and WHEREAS, installation of the 60kV tie breaker at the Colorado substation is essential to maintaining the reliability of the City’s electrical transmission system; and WHEREAS, unanticipated and required structural and electrical design changes to install the 60kV tie breaker have been discovered; and WHEREAS, additional funding of $i00,000 is requested for structural changes necessary to accommodate the 60kV breaker, to ensure seismic restraint requirements, and to provide an electrical relaying and protection investigation; and WHEREAS, Council authorization is needed to amend the 1995-96 budget, as hereinafter set forth NOW, THEREFORE, the Council of the City of Palo Alto does ORDAIN as follows: Section i. The sum of One Hundred Thousand Dollars ($i00,000) is hereby transferred from the Electric Fund’s Rate Stabilization Reserve to the appropriation for Capital Improvement Project Number 9509,~60kV Bus Tie Breaker Installation," reducing the Electric Fund Rate Stabilization Reserve by One Hundred Thousand Dollars(S100,000). SECTION 2. This transaction will reduce the Electric Rate Stabilization Reserve from $25,208,000 to $25,108,000. SECTION 3. As specified in Section 2.28.080(a) of the Palo Alto Municipal Code, a two-thirds vote of the City Council is required to adopt this ordinance. SECTION 4. This project has been determined to be categorically exempt under Section 15302 of the California Environmental Quality Act. SECTION 5. As provided in Section 2.04.350 of the Palo Alto Municipal Code, this ordinance shall become effective upon adoption. INTRODUCED AND PASSED: AYES: NOES: ABSTENTIONS: ABSENT: ATTEST:APPROVED: City Clerk Mayor APPROVED AS TO FORM:City Manager Senior Asst. City Attorney Deputy City Manager Director of Utilities