Vorotan HPPs Cascadе

The system of Vorotan Hydropower plant consists of 3 power stations, which are situated on the river Vorotan, on the area of the region Syuniq (former Sisyan and Goris regions) and use the waters of the river – bed and the streams as well.
The river has 178km length; the fall is 1223m, the natural annual flow is18,6m3/s for the link of Tatev. High mountain chains are linked to the pools of the river from the North, the South and the East, and the Zangezur mountain chain from the West and the South- West.
The source of the river is on the height of 3045m, it starts like a stream accepting numerous ponds and streams from the left and the right as well.
The system of the Hydro Power stations are formed from 3 stages. The total capacity is 404.2 MW, the annual average produce is 1.16 mln. KW/h.

The highest pressing station is the 3rd stage of the system – Tatev HPP. The descriptive feature of this plant is the turbine in the shape of ladle, which was first set in the area of the former USSR. The price of 1KW/h electricity set in this system is the lowest in Armenia.
The system of the Vorotan Hydropower plants is of the great importance in Armenian hydro system. The importance is big especially in the busy hours of the day in providing issue of determined burden.
The water stores of the system are also used for irrigation in village and town areas.
Since 1954 the designed work of the system has been launched and in 1961 it was under construction.
In 1970 December the firstling of the system – Tatev HPP was put in the action, in 1978 – Shamb and in 1989 – Spandaryan HPPs.
There are 4 storage lakes in the scheme of the system – one pool of long – term, seasonal, weekly regulation and daily regulation.
The common scheme of the system of Hydropower plants has the following picture:
In the area of Gorhayq and Tsghuk villages the main part of the system is built – Spandaryan reservoir, the water from here gets to Spandaryan HPP through the pressing tunnel. Beyond the HPP is built Angeghakot stronghold, which forms the reservoir of Angeghakot. From this reservoir not through the pressing tunnel the water is transformed to Tolors reservoir set on Sisyan and Ayri streams. From Tolors reservoir the water is transformed to Shamb HPP through the pressing tunnel. Beyond the plant is built Tatev reservoir which has the form of Daisy with rare building. From Tatev reservoir the water gets to daily regulation pool not through the pressing tunnel, wrom where goes to Tatev HPP through turbine pipe.

Vorotan HPPs cascade consists of 3 hydro power plants, placed on the River Vorotan  in the territory of the Syunik Marz, and they use both  the river and streams waters. HPPs Cascade consists of Spandaryan, Shamb, Tatev and ‘’Her-Her” hydro power plants with total installed capacity of 404.2MW, and  annual design  generation of 1.16mld KW/h.

Shamb HPP

The Shamb HPP is second stage in system
The main constructions of the plan are:
Head junction
Transferring tunnel
Tolors junction
Pressure tunnel and equaling hole
Turbine piping
Station junction
The head junction includes 35 m. concrete water dam which creates Angeghakot reservoir with total capacity of 3.4 million m3 and water remover with velocity of 198 m3/s.
The water is removed to Tolors reservoir with velocity of 18m3/s without pressure tunnel. The dam of the reservoir is constructed with local materials: the shield is sund-clay and has 69 m height and 188 m crest. Total volume is 96 million m3., useful -80 million m3. The nominal demharajin level is 1651.50 m, minimal - 1625,5 m.
The water remover of this junction includes trench pass water remover with 1651,5 threshold level and 88m3/s transmittivity , From the Tolors reservoir water flows along 6,9 km and with 75 m3/s transmittivity by the inclined tunnel and reaches station junction. At the end of tunnel there is an equaling hole with two cells which are conjugated by vertical stanchion. Afterwards water flows to the underground 1260 m turbine pipeline, which splits in to two parts 2, 2 m perimeter each that join two aggregates of the station.
The building of the station is located on the right bank of Vorotan on the rocky mountainside. It has capacity of 171 MW and 320 kW annual energy productions.
Water moves to Tatev reservoir by 77m length and 75 m3/s transmittivity water removing pipe, which forms common construction for both aggregates.
In front of each station there is bulb veal with 2200 mm perimeter.

Spandaryna HPP

Spandaryn is the first stage of Vorotan Cascade 
The main constructions of the plan are:
Spandaryna HPP hydro junction
Pressure inclined tunnel
Turbine piping
Station junction
Spandaryan HPP is the first stage of Vorotan Cascade. The junction consists of 83 m depth dam, constructed with local materials and clay- soil kernel. It has 315 m3 height comb and forms water distribution multiyear Spandaryn reservoir 
Total capacity of the reservoir is 257 mln. m3 , useful storage is 218 mln. m3. Nominal level is 2063 m, minimal 2030 m.
Hydro junction has 4 water receiving constructions, first- pressure tunnel, second- deep-laid water remover, third- Vorotan-Arpa tunnel (to deliver water to Sevan lake). Each of the parts has 30, 80 and 15 m3/s outlay respectively. The forth is the water removing construction with 103 m3 /s transmittivity and surface flow. 
The pressure inclined tunnel has 8 km length, 30 m3/s transmittivity. The tunnel ends with equaling hall with 1.9 thousand m3 volume. The unilinear turbine pipeline ends with 2 parts with 15 m3/s transmittivity that connects to 2 station aggregates.
Station has 76 thousand kW power, 210 mln. kW/h annual energy production. Counted pressure is 295 m. In front of each turbine there is bulb veal with 1400 mm perimeter.

Transformer – TD-80000/220/10.5
Initial power – 80 mW
Voltage in upper site- 242kW
Voltage in lower site- 10.5 kW 
Current in upper site -181 A
Current in upper site- 4400 A 

220kW BBE has H scheme, and it connects from above with 220 kW Vajk and Vorotan -1 air electricity lines and from below with generators, which connects to 220 kW number 1;2 oil micro volume switchers.
In years 1965-66 Y-220 micro volume switchers were changed to BMT-220 switchers.
All 7 generators of the system were produced by “Electrosila ” plant (St. Petersburg) , and speed regulators are produced by “Electropolt” plant.