Ensuring balance reliability in managing the development of electric power systems: condition, problems, information content

. The stages of improving the methodological and model support problem of balance reliability in recent years from the standpoint of developing new methodological instructions (MI) on the design of power systems are considered. The analysis of the developed and approved by the Russian Ministry of Energy and the impact of their application on the decisions made.


Introduction
The planning development of electric power systems (EPS) at all times has been given due attention.By the 90s of the last century, a hierarchical system was implemented, within the framework of which a strategy for the development of generating sources and power lines for the prospect of 5 to 20 years was developed.Methods implemented in software developments made it possible to solve problems related to development of the EPS development.Solving the problems of predicting the need for electric energy and power; optimization of the prospective development of generating capacities and the main electric network and today use the experience accumulated then.Unfortunately, this cannot be said about solving the problem of balance reliability (BR), from the standpoint of its influence on the creation of new or dismantling outdated generating sources in the management EPS of Russia development.Balance reliability in the task of managing the EPS development always and today is understood to ensure the demand for electricity and the power of consumers within the specified restrictions on energy supply, taking into account the planned and unplanned breaks in the operation of its elements.It is important to note that only those whose solution is related to the need account for the system failures due to emergency damage equipment and random load deviations caused mainly by the temperature factor.The difference between BR and other (regime, structural) is that random conditions caused by unplanned breaks can last several tens of days (unscheduled equipment repair).At the same time, the depth of possible power deficiency can reach significant values (tens of GW), when several large generators go into emergency repairs.
Exactly 10 years ago, at the 2013 seminar, at the request of N.I.Voropaya, we presented a reviewing report "Methodological foundations of studying the balance reliability of electric power systems", pub-lished in section 1.2 of the monographs [1].It noted that the BR task is complicated and multifaceted in our country, for known reasons from 1990 to 2010, it practically did not develop.The existing approaches to solving the problem of evaluating BR indicators and its synthesis, as well as the essence of the criteria for making managerial decisions on the substantiation of power reserves, were given.As a result, problematic issues were identified the tasks of ensuring BR in the new conditions of the transition from a centralized management system to the new paradigm of a multilateral process in the context of digitalization, multi -criteria and multiplicity of interests.They mainly came down to the following: -the formation of models calculated scheme EPS of Russia to study various tasks of balance reliability; -justification for new market conditions of criteria for making managerial decisions from the standpoint of ensuring balance reliability; -the formation of probabilistic indicators of frequency and duration certain types of repairs (capital, medium, current and emergency) for serial equipment; -the formation of probabilistic characteristics of a change in the load caused mainly by the temperature factor.In the material below, the authors allowed themselves to do an analysis of what happened in solving the problem of providing BR over the past decade (approximately since 2011).

Stages of improving methodological support.
As already noted until 2010, the task of providing BR was not so relevant.This is due to a sharp decrease in electrical consumption (in different regions from 10 to 40 %) during the reform period of the industry (90s).The impetus for the development of BR tasks was the Decree Russian Federation Government No. 1172 [2] regarding the procedure for long-term competitive power selection (CPS).
The procedure was focused on determining the paid generating power in the wholesale market, i.e. to identify ineffective generators.This process, a significant degree, depended on the parameter of demand for power in the power balance planned for the future period.The generating sources participating in the form and did not pass the selection were not payable when agreed with the Russian Federation Ministry of Energy, they could be dismantled.After the publication of this resolution with the EPS, the first attempt was pre-adopted aimed at forming new approaches to the justification level of reservation in the EPS, which is one of the components demand in the power balance.In 2011, the Institute Energosetproekt ordered a research [3] on the improvement, but outdated methodological recommendations (MR) 2003 [4].The percentage of the regulatory reserve of generating capacity (NRGC), which was obtained, with the assistance of our institute, did not arrange the customer, especially in terms of the repair reserve and were significantly increased to them.The stages of the change are given in table. 1 (column 1 -the results of our institute, column 2 -correction of the energy network project, column 3 -proposals for correction from the EPS, column 4 -proposed by the Ministry of Energy for approval).Methodological instructions (MI) 2012 were not approved for many reasons.Basically, they concerned use old information base (there was simply no other) and in the unreasonable overestimation of the repair component from 4.04 % (MR 2003) to 6.8 % in the amount of NRGC.The analysis above results shows a significant increase in relation to the values NRGC in the 2003 MR, proposed with the EPS (22.18 %, column 4) and in unreasonable MI in 2012 (20.5 %, column 5).Basically, the overestimation is associated with the component of the power repair reserve, in offers from the EPS by 2.5 times, MI 2012 by 1.5 times.In the last two lines of the table. 1 shows the parameters of regulatory power reserve for CPS European and Siberian parts EPS of Russia in the procedure.
It can be seen that the differences in the values of power reserves are significant.During the CPS procedure, the value NRGC in the Siberian EPS increased due to possible restrictions on the energy supply of the hydroelectric power station, by another 8.55 % [5].At the same time, NRGC was not accepted 12, as in the MR 2003, but 17 %.Given this, the increase NRGC for the CPS in the Siberian took a value of about 9 GW or 26.55 %.
From 2012 to 2014, our institute on assignment the SO UPS conducted research the problem of BR and, to a greater extent, of its component -the task of evaluating its indicators.By and large, they attempted to solve the problems posed in the mentioned monograph [1] and the introduction of this article.The tasks of information security in terms of probability information certain about unscheduled conclusions in the repair of generating equipment, chronological by hour of describing the power consumption modes and its random changes caused by temperature fluctuations.There were options for the formation models of calculated schemes EPS of Russia.Methods of evaluating random states were implemented, taking into account not only one, but also both law of Kirchhof [6].
In 2016, on instructions the SO UPS, the Institute completed research in a comparative analysis the level of operational power reserve [7] and new approaches to its substantiation [8].In the first work, a lot of attention was paid to the analysis of methodological approaches and model-program developments used in domestic and foreign practice to evaluate BR indicators and justify the values of operational power reserve.The above table.1 received in this work.It was given recommendations for the application of certain normative values to the BR indicators, depending on the accepted conditions for accounting for the electrical consumption mode [5].Unfortunately, they did not find proper reflection in the approved regulatory values of BR indicators for territorial zones in the probability of deficiency work ρnorm.= 0.996 [10] or the probability of a power deficiency н д J = 1 - ρ norm.= 0.004.The purpose "Justification of regulatory values", carried out in the same 2016, was to develop the recommendations corresponding to the name.We note two points.The first -the accounting of the power consumption mode was adopted by one December daily schedule, in the assumption of its actions on all working days of the year (as in the 2003 MR [4]).The second -the studies were conducted for the work EPS model presented by the customer SO UPS.The adoption of such a model of the calculated scheme, and not a model with fragmentation EPS and the achievement 50 territorial zones, as in the work of the Institute "Energosetproekt" can be explained by the results given in table.1.In the column fraction column 2, the values of the full and operational power reserves are given for the number of territorial zones equal to the EPS number, in the denominator-equal to 50.As you can see the differences in the levels of power reserves are insignificant and do not exceed even 0.5 percent.
According to the generating equipment, an information was actualized about its accident rate and the influence significant excesses the generating power of planned repairs used in the conditions of the equipment presence as a state of equipment.Repair with such a policy increased from 4.04 % to 8.87 %.Under the power consumption regimes, random load changes caused by temperature variations, taking into account their correlation dependence within the territories covered by EPS, were subjected to actualization.The results of the developed recommendations are given in the 2nd and 3rd columns table.2. In it, planned repairs on the recommendation with the EPS are adopted by 8.87 %.It can be seen that taking into account the correlation of the temperature factor leads to a significant increase in the value of the operational power reserve (9.99 and 6.86 %).The reduction in the percentage of the operational power reserve given in column 3 (6.86%) in relation to the column 2, table. 1 (8.97 %).This is due to a decrease in the average accident rate of generating equipment with 3.68 % [11] to today 2.77 %, a change in random load deviations from a given value and a factor in the availability of excess capacity relations.Recall that the results of the table. 1 obtained with optimization of access capacities.The results of the table.2 show that taking into account the correlation dependence of the temperature leads to a significant increase in the value of operational power reserve (by 3.13 %).It should be noted that the customer overestimation of the repair component on 4.83 % (from 4.04 % (table.1) to 8.87 %) is leaning this increase.Given this, the value NRGC, obtained at the new information base, amounted to only 14.03 %.
In February 2018, a competition was opened on the basis of the «Nonprofit Partnership Council for Organizing Efficient System of Trading at Wholesale and Retail Electricity and Capacity Market» to develop a generating power reserve of the Russian EPS.In March of the same year, the winners of the competition were recognized by two Academic Institutes of the Russian Academy of Sciences: ISEM SB RAS and the Institute for Socio-Economic & Energy Problems of the North, Federal Research Center Коmi Science Centre Ural Branch of the Russian Academy of Sciences (ISE&EPN FRC KSC UB RAS).In accordance with the terms of the contract, the work should have been completed within 6-8 months, but for unknown reasons were delayed.In December 2018, the ISE&EPN FRC KSC UB RAS, due to the reorganization and entry into the FRC of the Komi SC of RAS, left the contract (official version).Work with ISEM SB RAS continued and only by the end of 2020 the results were adopted by the customer of work.The results obtained by the ISEM of the SB RAS in terms of levels of NRGC for the EPS of Russia (approximately 13 %) [12] were agreed with the studies of the ISE&EPN FRC KSC UB RAS (table.1, 2nd line, 2nd column).It should be assumed that the procedure for determining the value of the NRGC proposed by ISEM was supposed to become the basis of the new methodological instructions for the design development of energy systems [13].
Almost all worked out from 2012 to 2016 in the framework of the work with SO UPS on the methodological support of the BR task, including taking into account the territorial correlation of random changes caused by temperature fluctuations in one form or another, included in the national standard of the Russian Federation [6].This can be attributed to the positive moments of the studies.It should be noted that the results of these studies were partially presented in the monograph [14] and work [15,16].Unfortunately, the studies of the ISE&EPN FRC KSC UB RAS and ISEM SB RAS did not find understanding SO UPS and the Russian Ministry of Energy on the substantiated values normative power reserve.It can be assumed that this is why they did not become the basis for the development of new MI.In the new MI, in accordance with the Federal Law "On Electro-Energy" No. 35-ФЗ dated 03/26/2003, a two-level planning model was adopted aimed at developing two software documents-a general scheme for the placement of electric power facilities and the development program (SDP) electric power systems of Russia .The substantiation of decisions to ensure BR in the development of these software documents, one way or another, is associated with the features formation power balance and the methodological provisions of the estimate and provision of BR.Two chapters (V and VI) are devoted to these issues.
Power balances initially imply the presence of equality between the receipt (generation) and the consumable (consumption) of its parts.At the very beginning of the chapter, it is noted that when forming power balance sheets, a calculated reserve should be taken into account, the concept of which is not found in further points of this and subsequent chapters.Instead, the concept (paragraph 87) of the required power of power plants is introduced to ensure power balance (P required ).Its determination is carried out from the conditions for ensuring the regulatory indicator BR (ρ norm ) (paragraph 113).At the same time, it is quite obvious that the difference between P required and the need value for power (P consumption ) (paragraph 82) is precisely the same calculated or NRGC.It should be emphasized that the concept of the required power is introduced only in the framework development (updates) the general scheme.For the development of SDP, this concept, as well as the concepts of excess and power balance, are completely ignored.
A distinctive feature of the new MI is introduction chapter "Ensuring Balance Reliability".In previous editions of MI and MR BR, it was ensured by the fulfillment of the requirements for the values NRGC of the territorial zones EPS.Their values were determined by multivariate calculations EPS and were given by the percentage maximum load [11].New MI is aimed at developing managerial decisions as a result of calculating BR indicators in the form of a probability deficit work (ρ).It is important to note that the need to increase the territorial zones power reserves and accessories of bonds is required when developing both software documents (paragraph 115).At the same time, the solution of the issues ineffective generating capacities (paragraph 116) and their dismantling (paragraph 117) can only be resolved only when developing or updating the general scheme that are relevant for modern electric power.
In the new MI algorithms for decision -making on the justification required capacity (P required ) and, therefore, the territorial zones NRGC EPS did not undergo changes in relation to the MR 2003.This cannot be said about the methodology for solving the problem of evaluating BR indicators.Changes are mainly associated with increasing information security.It should be noted that almost all probability defined information used to evaluate BR indicators is formed and used only by SO specialists and is not available to the scientific community.The alleged public discussions of the adopted management decisions, in our opinion, will be ineffective due to lack of the entire spectrum of source information among interested parties.

Assessment impact of changes introduced into new MI in the accounting of initial information on decisions made
The changes should include new approaches to accounting: electrical consumption modes (paragraphs 97, B, 106), Kirchhof laws (paragraph 109), models the EPS calculation scheme (paragraph 98), random power deviations caused by the temperature factor (paragraph 106).The influence of these changes are tested and partially published [6,14].At the same time, which included in the new MI related to the issues of accounting for planned equipment repairs (paragraph 102) and the representation the power of renewable power plants, including the hydroelectric power station (paragraph 83, D, G) were not tested and, moreover, they were not published.Below is briefly a analysis the influence of information on decisions the development and dismantling of equipment.
Presentation the power consumption mode.In many publications [9,14,16], the influence of various submission of the power consumption regime on decisions made was shown.Recall that in the MR 2003 and in the 2016 work report (link 5), the power consumption mode was presented by one daily load schedule of the month that lasts a calendar year.In the new MI, as in the national standard, the power consumption mode is represented by an annual hourly load schedule (8760 hours).
The normative indicator BR for the reliability territorial zones EPS in accordance with the order the Ministry of Energy No. 321 (link 6) remains unchanged and, as in the old MR 2003, equal to ρ norm.= 0.996.For this indicator in the table.2 (columns 4 and 5) include calculations the value of operational power reserve.As you can see, the values of power reserve are significantly different from the principles of accounting for the regime of electrical consumption used in the 2003 MR (columns 2 and 3).
Model the estimated scheme EPS and taking into account the Kirchhof laws.The new MI proposes use of a model with a large number of reliability zones than in the development of 2003 MR and with the condition implementation of both laws of Kirchhof when calculating randomly formed states of generating power.At the same time, throughput abilities are determined by restrictions on the transmission of power by sections obtained by calculation.Studies given in a number of publications [14] show sufficient discrepancies in assessing the regime when using different distribution of power deficiency (DPD) models.At the same time, when optimizing P required these discrepancies become not so significant due to the possibility of redistributing generating power between reliability zones.Experimental calculations show that an increase in the reliability zones estimated EPS model can lead to an increase in operational power reserve by a value not exceeding more than 0,5 percent of the maximum load (the number and denominator of the column 2 table.1), accounting of both Kirchhof laws maximum by 0,2 percent.
Accounting for scheduled equipment repairs.The approaches to the new MI to take into account the scheduled repairs of generating equipment are slightly different from the methodology used in 2003 MR.There are some explanations to certain types of generators.In any case, it can be stated that repairs should not exceed the average data.In accordance with [9], all types of planned repairs of generating equipment are 8.87 %.At the same time, approximately half falls on capital and average repairs, which is much higher than those in 2003 MR.This data was obtained during the work entire composition of generating equipment.They need to be adjusted to a really working composition, i.e. excessive excess.This accounting will reduce the amount of the repair reserve by about 2 %.
Presentation the power of renewable energy sources (RES), including hydroelectric power plants (HPP).In the new MI, as in the 2003 MR, the disposable capacities the HPP and RES are accepted equal to the established values, minus the restrictions caused by technical and regime parameters (paragraphs 83, D, G).There are no specific studies on such a representation of these stations types in the literature.During the CPS, NRGC in Siberia EPS increased by 8.55 % due to the restrictions of the hydroelectric plants.The studies presented in [5] showed the need to reduce this value to 4.5 %.Studies on the RES South EPS [17] showed that the influence of these types of stations on the NRGC value must be taken into account with their share in the production of electricity exceeding the 5 percent barrier.
Based on the calculations presented in this section and the results (table .2) following follows.The impact of changes in the presentation initial information in the new MI with existing regulatory requirements for BR indicators will lead to approximately the same parameters of the required power (P required ) or NRGC, which were also in the 2003 MR.Numerous calculations showed that the NRGC values for the UPS will fluctuate from 13.5 to 16.5 % (for our example -6.74+0.5+0.2+8.87-2= 14.31 %).

Conclusion
The introduction in the new MI section to ensure balance reliability will lead to negative consequences in the field of BR study.The reason lies in concentration of both the tools and the information component in one structure -SO UPS.Public discussions made from the SO UPS decisions on the industry development in this case are unlikely to be obtained.The reason is the impossibility of at least some verification of issues discussed in the discussion.This is clearly seen from the projects accepted at the turn of 2022/23.New MI 2022 entered into force on January 1, 2023 two days before, i.e. on December 30, 2022, the general scheme was updated until 2035 [18].It would seem that it was more logical to do this after the approval of the new MI.In our opinion, the adoption of such a decision was associated, in addition to other circumstances, by the requirements of new MI, in aspect the need to justify balance reliability.
In accordance with the above analysis, it is completely in vain that the BR indicators, with excessive power, presented in the materials actualized general scheme until 2035 and developed on its basis in 2023 of SDP materials at 2023-2028 [19] will significantly exceed the normative values.This contradicts the requirements of the new MI, in accordance with which, when developing a general scheme, it is necessary to bring the territorial zones BR indicators of the EPS to regulatory values (paragraph 116).This is achieved by multiple calculations of BR indicators with the withdrawal from the composition of the most emergency equipment.The derived generating equipment when fulfilling certain conditions paragraph 117, completely unrelated to the balance reliability conditions, should be subject to dismantling.

Table 1 .
Comparison the components of full power reserve for Russian UPS as a percentage of the maximum load.

Table 2 .
Influence of various representations power consumption regime on the components of Normative power reserve