Operating conditions of the hydroelectric stations of the Daugava multistage hydropower development

Conclusions

• 1. To solve the particularly urgent problem for the Northwest grid system of covering the peak-load part of the load schedule it is necessary to exhaust all possibilities of increasing the mobility of the electric stations. In the period up to 1970–1975 the use of the Daugava stations will be of decisive importance for solving this problem.

• 2. Owing to the pronounced nonuniformity of the streamflow distribution, to increase the participation of the Daugava station in the power balance these stations during the dry season should operate in the peak part of the load schedule of the integrated power system. This will necessitate the use of special methods of water-power calculations for the indicated hydroelectric stations and the provision of the technical means for realizing these regimes, In all probability this provisioning will be associated with automation of the distribution of the load increment in the grid system (regardless of automatic regulation of frequency and overcurrents).

• 3. Calculation of prospective operating conditions of peak-load stations by weekly, monthly, and seasonal load duration curves cannot provide (just as other methods of prospective calculations) a high accuracy. It is known that a slight decrease of the installed capacity lowers relatively little the economy of hydroplants, whereas a doubling of the capacity leads to its substantial deterioration.

• 4. Obviously there is no advantage in changing the planned installed capacities of the Plyavin'sk and Riga stations, and the selection of the capacity when expanding the Kegum station will change little the total capacity of the multistage development (even with the use on a limited scale of water storage at it). Therefore, basic attention should be devoted to the creation of additional regulating reservoirs.

• 5. As a whole the use of the Daugava hydroelectric stations as peak-load stations will be sufficiently effective even in the near future and now is the time to carry out the indicated measures.