Electric power quality control

The Company performs regular quality control activities by using special-purpose devices installed on connections which are close to points of supply to consumers.

In the reporting period the Company’s employees performed about 5,900 measurements for quality control purposes in 1,600 main substations.

Sometimes, it is mistakenly believed that the electric grid company is solely responsible for all detected violations relating to power quality; however, in most cases all of the energy sector participants, including consumers, are involved in the process of electric power quality management.

Based on the results of analysis carried out in 2011-2012 the following causes of defects in the power quality were detected:

• 28% of detected quality defects — asymmetry of loads in the consumer’s network (apartment buildings, group consumers, enterprises);
• 19% — increase in consumers’ loads above the established technical conditions and agreements made with the consumer and a rapid growth of privileged technological connection of consumers;
• 5-20% (depending on energy region) — non-linear load generated by consumers (harmonic components);
• 15% — violation of a mode of operation of on-load tap-changers (OLTC) (off-circuit tap-changers (OCTC)) by the electric grid company. As a rule, violations of OLTC mode are eliminated immediately or within 30 days and OCTC violations are eliminated depending on connection schemes and the necessity to disconnect the consumer, usually, within 30 days;
• 18% — non-conformance of equipment (lines, transformers) due to natural growth of loads of consumers and development of energy regions or worsening of the OL condition.

Electric power certification

IDGC of the North-West electric power undergoes a certification procedure. At the moment all of the main substations to which household consumers are connected are certified. In 2013 IDGC of the North-West plans to increase the number of power quality control devices by 20%, which will allow to increase the power quality control in future periods and, hence, to detect and remedy more causes of power quality defects.

Remedy of defects

Defects which are capable of remedy by the Company’s own effort are remedied within 30 days and defects requiring capital expenses are included in investment and repair programs which are reviewed and approved (or declined) by energy commissions of regional administrations. Defects caused by consumers of electric power are remedied by consumers themselves by elimination of affecting factors and the Company in this case is usually unable to influence the period of remedy within the legal framework.

Thus, consumers distorting the grid or organizations servicing and operating consumer’s networks (household companies, housing cooperatives) are responsible for 52-67% of all defects, depending on the energy region.

In rural areas persons carrying out illegal connection to the grid or stealing power are greatly responsible for worsening of the power quality. For example, illegally connected electric heating of houses and growing rooms may cause asymmetry of voltages in the entire village and, therefore, failure of electric receivers of some residents and low voltage in houses of others.

In apartment buildings if a household company does not control and equate the load by phases, the same may happen in apartments of the building despite the fact that the electric grid company supplies energy of proper quality to this village or apartment building. Certain consumers, such as electric trains of Russian Railways, ore mining and processing mills and other facilities, also introduce distortions in the grids of large energy regions.