Malburg Generating Station
Application for Certification5.0 Transmission Facilities
5.0FACILITY CLOSURETRANSMISSION FACILITIES
This section discusses the interconnection between the MGS and the existing Vernon Substation. Included are a description of the existing transmission system and proposed interconnection, and a discussion of the results of the System Impact Study (SIS). Because no new transmission lines will be constructed as part of the MGS, there will be no adverse impacts associated with transmission system safety or nuisance.
5.1Existing Transmission System Description
The City’s transmission line information is presented in Table 5-1. The interconnection work that will be done for the MGS project consists of the construction of three underground 69 kV connections inside the existing generating station property. Two will connect between the two new MGS CTG step-up transformers and the Vernon Substation. The third will connect the MGS STG to the Vernon Substation. Each line will be approximately 300 feet in length. Each line will terminate in a new 69 kV bay in the Vernon Substation.
The existing Vernon Substation consists of seven positions, as follows:
- Laguna Bell-Leonis
- Beejay-Kinetic
- Vernon sub No. 1 Bank
- Vernon Sub No. 2 Bank
- Owill
- Container-Laguna Bell-Pulpgen
- Vernon sub No. 3 Bank
All 69 kV circuit segments are summarized in Table 5-1. Figure 5.1-1 shows One Line Diagram of the Vernon Substation.
The existing transmission lines extending into the City are owned by the City inside the City and by Edison outside the City. There are five such lines, each rated at 800 amps continuous and 960 amps emergency. The two new CTGs will each add 376 amps and the STG will add 481 amps.
5.2Interconnection System Impact Study
The City conducted a SIS for interconnection of the proposed MGS to the existing Vernon Substation. This study includes the effects of the existing co-generation facilities located within the City, the Johnson & Heinze Diesel Plant, the H. Gonzales Generating Station, and the proposed MGS. The Vernon Substation one line diagrams for operation and for construction (Figures 5.2-1 and 5.2-2) show the before and after configurations at the Vernon Substation. The impedance diagram (Figure 5.2-3) shows all relevant loads and generation sources. The SIS includes short circuit studies, power flow analysis and transient stability studies. This section includes a summary of the results of the City’s SIS, and an analysis of the potential system impacts for the ultimate 134 MW of additional generation at the Vernon substation. Appendix D presents the complete System Impact Study Report.
The SIS conducted by the City for this Project demonstrated that the five existing 800 amps, 69 kV, transmission lines are capable of supporting the 134 MW addition at the Vernon Substation. Therefore, no new transmission facilities are required. The only modifications required are those required at the Vernon Substation.
The results of the City’s SIS have been submitted to Edison.
5.2.1Study Conditions and Assumptions
The SIS was conducted by applying the City’s System Planning Criteria and Guidelines and Cal-ISO Reliability Criteria. The SIS was based upon 2005 projected peak loading.
5.2.2Power Flow Analysis
The two power flow analyses were conducted based upon projected 2005 loading. One analysis was conducted using the existing system and the second was conducted by using the existing system plus the new MGS generation and two lines out of service.
The worst case occurs under the second condition and results in 501 A in the Vernon Owill and Owill Leonis lines.
5.2.3Transient Stability Study
The stability criterion utilized is that the transmission system is to remain stable under a three phase fault at the most critical location with the fault normally cleared and with the loss of one or two transmission lines. This analysis was performed for five critical contingencies based upon year 2005 system loading. All transient stability cases were found to be stable, therefore, the report concluded that the proposed addition does not affect stability.
5.2.4Short Circuit Study and Facility Study
The short circuit study was conducted by simulating all generation sources on line and all 69 kV lines in service. This represented the worst case total short circuit current. Results of this study indicate that it is necessary to replace all 69 kV breakers at Vernon Substation, replace all 69 kV breakers at Leonis Substation and replace all 69 kV breakers at Owill Substation.
The City had previously initiated a 5-year program for its 69kV breakers. The existing breakers are over 30 years old and spare parts are difficult to obtain. The City has accelerated its replacement program to be concurrent with development of the MGS project.
Facility closure can be temporary or permanent. Temporary closure consists of a cessation in operations for a period of time greater than the time required for normal maintenance, including overhauls or replacements of major equipment. Potential causes for temporary closure include economic conditions or repairable damage to the plant from earthquake, fire, storm, or other such events. Permanent closure consists of a cessation in operations with no intent to restart operations. Potential causes for permanent closure include age of the plant, economic conditions, or irreparable damage to the plant. Temporary and permanent facility closures are discussed in the following sections.
TEMPORARY CLOSURE
In the event of a temporary closure, 24-hour security for the facility will be maintained and the CEC will be notified. Actions taken will depend on whether the temporary closure involves a release of hazardous materials.
If there is no release or threatened release of hazardous materials, a contingency plan for the temporary cessation of operations will be implemented. The contingency plan will be conducted to ensure public health and safety, protection of the environment, and conformance with all applicable laws, ordinances, regulations, and standards. Appropriate procedures will depend on the expected duration of the shutdown. Accordingly, the contingency plan may include the draining of chemicals, water, and other fluids from storage tanks and plant equipment and various other procedures to ensure worker safety and to protect plant equipment. All hazardous and non-hazardous waste materials will be collected and disposed of as described in Section 8.12.
If there is a release or threatened release of hazardous materials, procedures set forth in a Risk Management Plan (RMP) will be implemented. The RMP to be prepared is described in Section 8.12. Procedures include methods to control releases of hazardous materials, notification of appropriate authorities and the public, training for plant personnel, and other emergency response actions and preparation. Once the release of hazardous materials has been contained and cleaned up, temporary closure will proceed as in the case of a closure where there is no release of hazardous materials.
PERMANENT CLOSURE
The planned operational life of the facility is 30 years. However, if the facility continues to be economically viable, it could be operated for a longer period of time. Operation beyond 30 years would defer environmental impacts resulting from the construction of replacement facilities. It is also possible that the facility could become economically non-competitive before 30 years have transpired, forcing early decommissioning. Whether the facility is closed at the expiration of 30 years, after more than 30 years, or prior to 30 years due to economic or other reasons, procedures set forth in a decommissioning plan will be implemented. The decommissioning plan to be prepared is described below.
To ensure public health and safety, protection of the environment, and conformance with applicable laws, ordinances, regulations, and standards, the decommissioning plan will be submitted to the CEC for review prior to commencement of permanent facility closure measures. Such measures may range from extensive “mothballing” to removal of all equipment and appurtenances, depending on circumstances at the time. However, future conditions that would affect decommissioning decisions are largely unknown at this time. It is therefore appropriate to present decommissioning details to the CEC and other jurisdictional agencies when more information is available and the time for permanent facility closure has drawn closer.
The decommissioning plan will include the following:
Description of the proposed decommissioning measures for the facility and
for all appurtenances constructed as part of the facility.
Description of the activities necessary to restore the site if the decommissioning plan calls for removal of all equipment and appurtenances.
Discussion of decommissioning alternatives other than restoration of the site.
Presentation of the costs associated with the proposed decommissioning measures and the
source of funds to pay for the decommissioning.
Discussion of conformance with applicable laws, ordinances, regulations, and standards and with local and regional plans.
In general, the proposed decommissioning measures will attempt to maximize the recycling of all facility components. Unused chemicals will be sold back to the suppliers or other purchasers where practicable. All equipment will be shut down and drained so as to ensure public health and safety and protection of the environment. All hazardous and non-hazardous waste materials will be collected and disposed of as described in Section 3.4.7. Until decommissioning activities have been completed, 24-hour security for the facility will be maintained.
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K:\Reports\R1382 (Vernon-Combined Cycle)\AFC\5.0 Transmission Facilities.doc10/30/18
Malburg Generating Station
Application for Certification5.0 Transmission Facilities
Table 5-1
City of Vernon Transmission Line Information
Substation / To
Substation / Line Length
(Miles) / Voltage
(kV) / Continuous
Rating
(Amps) / Conductor
Size
Laguna Bell / Vernon / Pulpgen / 5.2 / 69 / 800a / 653.9 ACSR
Laguna Bell / Ybarra / 4.7 / 69 / 800a / 653.9 ACSR
Ybarra / Leonis / 0.96 / 69 / 800a / 653.9 ACSR
Laguna Bell / Leonis / Vernon / 4.99 / 69 / 800a / 653.9 ACSR
Laguna Bell / Leonis / Coldgen / 4.8 / 69 / 800a / 653.9 ACSR
Laguna Bell / Leonis / Growgen / 5.3 / 69 / 800a / 653.9 ACSR
Leonis / Owill / 0.58 / 69 / 800a / 653.9 ACSR / 1750MCM
Owill / Vernon / 0.19 / 69 / 800a / 653.9 ACSR
Leonis / Vernon / 0.80 / 69 / 800a / 653.9 ACSR
a960 A emergency rating
5-1
K:\Reports\R1382 (Vernon-Combined Cycle)\AFC\5.0 Transmission Facilities.doc10/30/18
Malburg Generating Station
Application for Certification5.0 Transmission Facilities
5-1
K:\Reports\R1382 (Vernon-Combined Cycle)\AFC\5.0 Transmission Facilities.doc10/30/18