Website Case Study – SSR5B
As part of a power reinforcement project, ISS Ltd carried out significant HV works across various sections of the London Underground network to improve network capacity and improve overall network resilience and enhance robustness.
The brief work scope included;
- Design Production, including drawing packs, Protection & PSL files, ITP’s.• Project & Commissioning Management.
- Install & Commission into service new 9 panel ABB ZS1 11kV Switchboard at Mile End, and de-commission and remove redundant switchboard.
- Install & Commission into service new 32 panel ABB ZX2 Switchboard at Mile End, and de-commission and remove redundant switchboard.
- Install & Commission into service new IEC61850 RTU’s and HMI interfaces at Mile End.
- Install & Commission of new Batteries & Chargers, and Changeover contractors at Mile End.
- Install & Commission into service a 22kV Schneider YSF6 extension panel at Stratford to the existing switchboard.
- Install & Commission into service a 22kV ABB ZX2 Extension Panel at West Ham to the existing switchboard.
- Install & Commission into service a 22kV ABB ZX2 Extension Panel at Cobourg Street to the existing switchboard.
- Re-locate West Ham 22kV Auxiliary Transformer circuit to new bus-section.
- Re-designate West Ham 22kV Circuit to become a Feeder Unit Protection.
- Manufacture, install and commission into service 26 No. Line Differential Feeder Protection panels onto existing 11kV & 22kV switchboards across the network to communicate with the newly installed switchgear.
This was a challenging project to deliver on an operational railway. There were space restrictions at Mile End, so construction was delivered in a phased manner.
The new 11kV ZS1 Switchboard installed and pre-commissioned, with all power and control cabling installed ready to change over. Each circuit was transferred sequentially, along with the installation of the Line Differential Feeder Protection panels at the associated remote ends.
The 11kV IEC 61850 RTU & HMI was installed and commissioned. Each circuit was changed over and commissioned sequentially during engineering hours, maintaining operation at all times.
Following the changeovers, we dismantled and removed the redundant sections of the 11kV switchboard.
Challenges included design and installation of the Restricted Earth Fault protection interfacing with the existing Neutral Earthing Transformer and existing 22kV switchboards.
We faced challenges when installation the new 22kV ABB ZX2 switchgear. Once the redundant 11kV switchboard was removed, we installed and commissioned the first half of a 3 section 22kV double busbar switchboard and transferred circuits from the first 3 sections of the existing 22kV switchboard.
The 3 sections of redundant 22kV switchboard were then removed making way for the remaining 3 section double busbar switchboard to be installed and commissioned adjacent to the first half of the 22kV switchboard. Challenges included integrating the interlocking and bus zone protections from the 3 busbar sections in service to the remaining 3 sections without disruption to the operational railway and power supply network. See pics 1 & pics 2 (figure 2) of the staged installation and changeover works.
The 22kV IEC 61850 RTU & HMI was installed and pre-commissioned, with all power and control cabling installed, allowing each circuit to be changed over and commissioned sequentially during engineering hours, along with each of the Line Differential Protection panels.
We installed and commissioned a new RITZ fully insulated 22kV SIS Busbar Inter-connector in the basement area, running below the switchgear linking both halves of the switchboards. After which we completed the detailed programme of changeovers, bringing each of the circuits into service, including the installation and commissioning of the Line Differential Protection at various substation across the network, bringing us to pic 4 showing the final 22kV configuration.
As part of the 22kV installation works, ISS built a CT chamber in the basement, mounted the Current Transformer and ran the HV cables through the basement and up into the 22kV switchgear.
New 22kV extension panels where installed and commissioned at Stratford (Schneider YSF6) and Cobourg Street (ABB ZX2), with circuit re-designation works undertaken at each site, along with remote end Line Differential Protection upgrade works.
Similar Line Differential upgrades where carried out across the network as part of this project, including Main Protection and Backup Protection and associated current transformers. Often replacing the old MBCI and SPAC638C relays with new RED 615 and Agile P14 relays as shown in figure 4. The new protection was pre-commissioning and Line Differential tested back to the new 22kV switchboard.
The protection fascia (1 of 29 fascia’s for the project) was designed and manufactured by ISS in our production facility, who then handed the mantle to the ISS site teams for the installation and commissioning of the remote end protection upgrades to a tight programme of 11kV & 22kV changeovers, sequentially bringing into service each of the circuits into service.
