Germany - Parts for electric motors and generators

Description

Vattenfall Wasserkraft GmbH (VWK) operates the Hohenwarte II pumped storage power plant (PSW Hoh II) on the upper reaches of the Saale River in the Saalfeld-Rudolstadt district. Eight pumped storage units (PSS) were commissioned at this power plant in the period 1963 - 1966.The PSS have the following technical data:Rated power motor generator 50 MVRated power turbine operation 40 MWRated power pump operation 42 MWRated voltage 10.5 kVRated speed 428.6 min-1Instantaneous speed 700 min-1Mass rotating part 135 t (motor generator) + 34 t (turbine) + 28 t (storage pump)Moment of inertia 860 tm²Outer diameter brake track 2.850 mmWidth of brake track 300 mmThe lower support star is located below the generator stand. Four oil-hydraulically actuated, single-acting brake cylinders with piston return springs are located on the arms of this support star. Mechanical braking is achieved by hydraulically pressing brake pads against the brake track on the generator rotor.This mechanical braking device is used to shorten the run-down phase of the rotating part of the PSS. The motor-generator is braked electrically during normal operation, so the mechanical brake functions mainly as a standstill brake. Only in the event of failure or prohibition of electrical braking is it used for rapid shutdown. Furthermore, it is used to lift the generator rotor during repair and maintenance work.The subject of the invitation to tender is the dismantling and disposal of the mechanical braking and lifting systems as well as the design, manufacture, supply, installation and commissioning of new mechanical braking systems on all eight PSS in identical design.The first retrofit of a brake system is to take place within the scope of the interim overhaul of PSS C, which is planned from 07.08.2023 to 26.04.2024 (date adjustments on the part of the AG are possible).The other seven retrofits are to take place within the scope of further call-offs (options) within subsequent, planned shutdowns. In order to enable both effective work planning by the contractor and long-term shutdown planning by the customer, information in accordance with the "Brake system renewal performance specification" appendix must be supplied with the bid.
Scope of work: The oil lines previously used for the hydraulic brake system incl. the valves up to the combination valve block Mg31c (P3 % 3MEX00 AA602 and P3 % 3MLA40 AA751) are to be dismantled and handed over to the customer for disposal, the flanges/openings are to be closed properly, the four brake blocks of the first rebuild lot are to be carefully removed and handed over to the customer for possible further use (their reconditioning is not part of this scope of services), for the further rebuild lots the respective dismantled brake blocks are to be handed over to the customer for disposal.The existing manually operated oil unit for lifting the pole wheel is to be integrated into the new piping, as it is to be used for safety measures (application of the brakes during longer stoppages without existing pressure from the DÖR).Four double-acting brake blocks are to be supplied and installed at the existing assembly points, which are pressurized with oil (20 bar ± 15 %) via two ring lines on the "brakes applied" side or the "brakes released" side (the exact interfaces are to be proposed by the contractor, from where new lines are to be supplied and installed up to the brake blocks). The circumference of the ring lines shall be designed to be disassembled and reassembled as quarters by means of "whale shape + bolting". From this ring line circuit, screwable line sections of easily manageable length are to be provided. A leakage oil line and a drain line from both pressurized sides including shut-off valves (corresponding to fitting P3 % 3MLA40 AA401) are to be laid up to the associated oil reservoir in order to be able to carry out safety measures on the hydraulic system. The lengths of the individual lines are to be measured by the contractor, for calculation purposes approx. 40 m each can be assumed. A solenoid valve (suitable for permanently applied coil voltage 220 V DC +15/-20 %, exact type to be agreed with the customer) is used to control the braking system. This solenoid valve is mounted on the pressure oil unit. The electrical connection of the solenoid valve is made by the customer. In order to establish the safety measures (shutting off the braking system, draining/pressure relief), appropriate fittings must be provided at the supply point (pressure oil unit).Travel sensors (preferably make TURCK Ni50-Q80-LiU-H1141 with 24 VDC control voltage) must be installed on the new brake blocks, which measure the entire travel as a 4.The brake blocks are to be equipped with brake linings (asbestos and metal-free, preferably from STS Friction GmbH, type STS2010 or equivalent) riveted to suitable steel plates. When the wear limit is reached (please specify), it should be possible to replace these carrier plates with the worn brake linings by loosening a few (secured) screw connections due to the confined installation space.All screw connections used in the interior of the engine generator must be secured against loosening (preferably Nord-Lock washers, alternatively lock washers with reversible lugs). The new braking system must be designed in such a way that the braking effect achieved does not exceed the previous braking times.

Opportunity closing date

23 October 2023

Value of contract

to be confirmed