Start-up operations at the Sayano-Shushenskaya HPP unit No.6 in progress

The general designer JSC Lengidropoekt has confirmed compliance of all the process systems and hardware of the hydro-unit No. 6 to the technical design specifications.
All the repair and restoration works were arranged according to the results of inspection by manufacturers’ experts and specialized research institutions. The scope of inspection included foundation slabs, building and metalwork structures, flow passage of the unit, the turbine, the generator, auxiliary and general-purpose plant’s equipment, power output circuit. Completely reconditioned systems of excitation, control, protection and automation have been installed and adjusted. Generator No. 6 circuit breaker equipment has been replaced. Equipment of main outputs chamber, zero terminals chamber has been reviewed. Switchboard for unit’s own purposes has been commissioned. Fire-extinguishing system for the cable galleries has been tested.
In addition to the above-mentioned works, the operational testing was preceded by special measures to ensure safety of hydro units operation. Specifically, measures prescribed by supervising agencies were completed. These included: approval of the Safety Declaration for the SSHPP hydro technical facilities, instrumentation of hydro units with regular systems of continuous vibration control, testing of the steel and concrete penstock tunnels technical condition, drawing of the Provisional Operational Regulations for Sayano-Shushenskaya HPP Hydro-technical Facilities and the Measures to ensure safe operation of the dam and hydraulic-jump basin of the SSHPP when no water passes through units in winter, examination of SSHPP hydro technical facilities by expert commissions.
Design solutions for the automatic control system of process control pertaining to control of the turbines, protection and blocking devices which are to secure safe and reliable cutting-off the equipment in contingency situations have been modified and implemented. For example, the alarm warning of the vibration control system was perfected to implement the function of automatic shutdown of the hydro units. The turbine governor has been updated to ensure the distributor shutdown in case of power supply failure. Mounting studs of the turbine cover and other units were replaced by new ones and underwent ultrasonic testing. Measures were taken to prevent loosening of nuts as was prescribed by Hydroturbomash design bureau.
Two Diesel emergency power supply units were installed on the crest of the dam for circuits controlling emergency gates and lift cranes. Stand-by duty of operating staff on the crest of the dam has been established for handling the gates. Control circuits for emergency gates and units’ shutdown by command from the main board switch and the unit’s control switchboard have been implemented.
To provide for industrial and personnel safety, all operations are carried out strictly to job orders and under ongoing monitoring by operating crews and reliability and safety service personnel of the SSHPP. HPP and contractor employees were briefed as to the emergency response procedures and took part in an integrated joint emergency response exercise. An industrial TV system was installed in the units Nos. 5 and 6 main lead area, process passageways and rooms of the turbine building, emergency and repair gate control devices, and at the overfall divide to provide for visual situation monitoring.
A total of 11 camcorders were installed to monitor units Nos. 5 and 6 operation. An emergency alert system was set up in the turbine room. All welfare rooms, including those of the contractors, were removed from the potential flood zones to flood-safe areas. All workstations were equipped with acoustic and light warning systems, and radio and telephone communications facilities. Idle running is a normal mode of a hydroelectric unit, meaning its off-load unrestricted longtime operation.
Idle running is an indispensable condition of the unit’s soak test after its repair, rehabilitation and upgrading designed for checking on and assessing the status of its mechanical and electrical parts, and control systems. Owing to the unit’s design features in terms of heating and airflow, idle running is one of the most effective ways for the post-repair drying of the unit’s electric insulation to restore its parameters back to normal.
During the idle running of unit No. 6, the hydroturbine, manual governor control and automated oil pressure installation control parameters were checked in accordance with the startup test program. The test data were recorded in the relevant certificates signed, among others, by representatives of JSC Power Machines. The measured vibration parameters testify to the high quality of the repairs performed.
Unit on-load grid connection is the process of equipment startup involving the startup of the turbine, hydrogenerator, transformer, and secondary equipment whereby the turbine is set in motion and begins to spin, the generator is excited, the unit transformer is switched on, generator and power-line frequencies are synchronized, the generator is put under load, and load is increased and decreased.
The main SSHPP rehabilitation objectives for 2010 are as follows:
— startup of hydroelectric units Nos. 5 and 6 (unit No. 6 in February 20-28, 2010 (ahead of schedule), and unit No. 5 in March 20-30, 2010);
— rehabilitation of units Nos. 4 and 3 before the end of 2010, and commissioning of shore spillway phase 1 by June 1, 2010.