The Supply Delivery Installation and Commissioning of a Power Distribution System

In accordance with Regulation 41 of the Public Contracts (Scotland) Regulations 2015, the University is issuing this notice to undertake Preliminary Market Consultation prior to commencing any live procurement process. The University of Strathclyde (UoS) seeks expressions of interest from suppliers capable of providing a DC Power Distribution Cabinet (PDC) solution to support the expansion of testing capability within the ANZIC facility.

The market engagement will explore supplier capability, technical solutions and delivery models for a requirement expected to include a PDC incorporating active and passive insulation monitoring functionality. This lot will include: Design, manufacture, supply, testing, delivery and commissioning of a mobile, indoor DC Power Distribution Cabinet capable of distributing power between multiple DC sources and loads at operating voltages up to 1500 VDC.

The cabinet shall incorporate common positive and negative DC busbars with a continuous withstand current rating of 2500 A, together with an IT-system reference and bonding bus. Internal creepage and clearance distances shall be appropriate for the nominal system voltage, and the cabinet shall be designed and constructed in accordance with applicable standards, including IEC 61439, IEC 60664 and IEC 62477.

The cabinet shall provide a minimum of 14 positive, 14 negative and 16 IT-system earth or bonding connections. DC connections should use PowerSafe/Powerlock-style panel connectors rated to 800 A, with red L1-keyed panel-drain connectors for positive terminals and black L2-keyed panel-drain connectors for negative terminals.

The external IT-system earth bar shall support the connection of external equipment through bolted lugs using 16 equally spaced pre-drilled holes. Provision of PowerSafe earth panel connectors is also desirable.

The enclosure shall provide suitable mounting space, power supplies, cable-routing paths and interfaces for the active and passive insulation monitoring equipment described under Lots 2 and 3. It shall also provide accessible and clearly labelled busbars, facilities for measuring the potential between the positive and negative DC poles, and safe access for inspection, maintenance and the removal or replacement of major components.

The cabinet shall achieve a minimum ingress protection rating of IP32 and incorporate appropriate thermal management for all installed equipment. It shall be capable of movement within the facility using industrial castors with locking brakes, or a base frame suitable for transportation by pallet or forklift truck.

The overall dimensions shall be less than 2.8 metres in height and less than 2 metres in both length and width. The scope shall include general arrangement drawings, equipment warranties, busbar and thermal calculations, test certificates, maintenance manuals and all other documentation required to demonstrate a safe, compliant and operational solution.

Additional information: Please note that the proposed lot structure remains under review and may be subject to revision as the procurement approach is finalised. This lot will include: Design, supply, integration, testing and commissioning of an active insulation monitoring system for incorporation within the DC Power Distribution Cabinet and operation on an IT earthing system at voltages up to 1500 VDC.

The system shall incorporate an Isometer or technically equivalent insulation monitoring device capable of detecting insulation resistance down to 1 kΩ and operating with a system capacitance of up to 1000 µF. The scope shall include the insulation monitoring device, associated power supply, mounting arrangements, protection equipment, cable-routing paths and connections to the positive and negative DC busbars and IT-system bonding arrangements.

The active monitoring system shall continuously monitor insulation resistance and support the detection, indication and investigation of insulation faults within connected DC sources, loads and associated equipment. The active monitoring system shall be coordinated with the passive resistor bridge described under Lot 3.

The design shall allow the resistor bridge to be isolated from the positive and negative DC busbars when active insulation-resistance testing is required, preventing the low impedance of the resistors from influencing operation of the Isometer. The interface should preferably permit external isolation through panel-mounted switches with a clear indication of isolation status, without requiring the removal or opening of cabinet access panels.

The scope shall include all necessary design and interface information, configuration, functional testing, calibration where applicable, commissioning support, test certification, warranties, operating instructions and maintenance documentation. Additional information: Please note that the proposed lot structure remains under review and may be subject to revision as the procurement approach is finalised

This lot will include: Design, supply, integration, testing and commissioning of the passive insulation monitoring and associated electrical measurement equipment for incorporation within the DC Power Distribution Cabinet. The passive monitoring system shall include a resistor bridge comprising one resistor connected between positive DC and the common earth electrode and one resistor connected between negative DC and the common earth electrode.

The resistors shall have nominally equal resistance values of 600 Ω and each shall be capable of continuous operation at 600 VDC across its terminals and dissipation of 600 W. In normal operation, the nominal voltage across each resistor is expected to be approximately half the overall system voltage, with an anticipated current of approximately 0.5 A through the series arrangement.

The resistors shall establish a virtual midpoint between the positive and negative DC poles for IT-system integrity monitoring. They shall be mounted to permit safe inspection, removal and replacement, with appropriate spacing, ventilation and thermal management to dissipate the heat generated during operation.

The resistor bridge shall be capable of isolation from both the positive and negative busbars, preferably through externally accessible, panel-mounted isolation switches providing a clear visual indication of isolation status. The scope shall include a high-quality DC current transducer, using Hall-effect or equivalent technology, installed between the resistor midpoint and the common earth electrode or bonding bus.

The transducer shall have a measurement range of 0 to 5 A and sufficient resolution to detect changes of 1 mA. A suitable power supply shall be provided for the active sensor, together with external connections through fused instrumentation-voltage terminals, such as banana sockets, to enable connection of external measurement equipment.

The system shall also include an internally mounted voltage transducer capable of monitoring the DC potential between the positive and negative busbars at voltages up to 1500 VDC and providing a ±10 V external output. This may comprise a Verivolt IsoBlock V-1c or an equivalent product, together with a suitable power supply, protection arrangements, monitoring points and external instrumentation connections.

The IT earthing arrangement shall include an internal earth or bonding bar connected to the midpoint of the resistor bridge. The resistor midpoint shall connect at one end of this bar, with all other bonded connections positioned on one side of that point, allowing the associated insulation-monitoring current transducer to be located between the resistor midpoint and all other bonded elements.

The system shall also provide an external earth or bonding point suitable for the equipotential bonding of multiple connected power devices through bolted-lug connections. The scope shall include all necessary equipment, wiring, protection, isolation, thermal calculations, functional testing, calibration where applicable, test certification, warranties, operating instructions and maintenance documentation. Additional information: Please note that the proposed lot structure remains under review and may be subject to revision as the procurement approach is finalised.