Power supply and network circuits


Requirements to utility power systems and network circuits

Chapter 1.2. Power supply and network circuits (It is coordinated with the State Committee for Construction of the USSR on August 3, 1976; it is approved as Glavtekhupravleny and Gosenergonadzor of the Ministry of Energy of the USSR on July 5, 1977)

Comment of the GUARANTOR
Since January 1, 2003 chapter 1.2 of section 1 of "Regulations for electrical installation" of the 6th edition became invalid. See chapter 1.2 of the section 1 "Power Supply and Network Circuits" in the editorial office of the 7th edition approved by the order of the Ministry of Energy of the USAn Federation of July 8, 2002 N 204.

Scope, definitions

1.2.1. The present chapter of Rules extends to all utility power systems. Utility power systems of underground, traction and other special installations, except requirements of the present chapter, have to conform also to requirements of special rules.

1.2.2. The power generating system (power supply system) is called the set of the power plants, the network and thermal circuits connected among themselves and connected by community of the mode in continuous process of production, transformation and distribution of electrical energy and warmth at the general management of this mode.

1.2.3. The electric part of the power supply system is called the set of electric units of power plants and network circuits of the power supply system.

1.2.4. Electric utility system is called the electric part of the power supply system and receivers which are powered from it integrated by community of process of production, transfer, distribution and consumption of electrical energy.

1.2.5. Power supply is called providing consumers with electrical energy. The utility power system is called the set of the electric units intended for providing consumers with electrical energy.

1.2.6. The centralized power supply is called power supply of consumers from the power supply system.

1.2.7. The network circuit is called the set of electric units for transfer and distribution of electrical energy consisting of substations, distributing devices, current-conducting wires, air (VL) and cable transmission lines working at the certain territory.

1.2.8. The receiver of electrical energy (electroreceiver) is called the device, the unit, the mechanism intended for transformation of electrical energy to other type of energy.

1.2.9. The consumer of electrical energy is called the electroreceiver or group of the electroreceivers integrated by technology process and which are placed in the certain territory.

1.2.10. The independent power source of the electroreceiver or group of electroreceivers is called the power source on which tension in the limits regulated by these rules for postemergency operation at its disappearance on the friend remains or other power sources of these electroreceivers.

2 sections or the systems of tires of 1-2 power plants and substations are among independent power sources at simultaneous observance of the following 2 conditions:

General requirements

1.2.11. At design of utility power systems and reconstruction of electric units the following questions have to be considered:

At the same time have to be considered in the complex external and internal power supply taking into account opportunities and economic feasibility of technology reservation.

At the solution of questions of reservation it is necessary to consider overload capacity of elements of electric units and also availability of the reserve in processing equipment.

1.2.12. At the solution of questions of development of utility power systems it is necessary to consider repair, emergency and postemergency operation.

1.2.13. At the choice of the independent mutually reserving power sources which are power supply system objects it is necessary to consider probability of simultaneous dependent short-term decrease or total disappearance of tension for the period of action of relay protection and automatic equipment at damages to the electric part of the power supply system and also simultaneous long disappearance of tension on these power sources at severe system accidents.

1.2.14. Requirements 1.2.11-1.2.13 have to be considered at all intermediate stages of development of power supply systems and utility power systems of consumers.

1.2.15. Design of network circuits has to be carried out taking into account the type of their service (continuous watch, watch at home, mobile teams, etc.).

1.2.16. Work of network circuits of 3-35 kV has to be provided with the neutral isolated or grounded via arc-suppressing reactors.

Compensation of the capacity current of ground fault has to be applied at values of this current in standard duties:

At earth fault currents more than 50 And application not less than 2 grounding arc-suppressing reactors is recommended.

Categories of electroreceivers and ensuring reliability of power supply

1.2.17. Concerning ensuring reliability of power supply electroreceivers are separated into the following 3 categories:

  1. Category electroreceivers I - electroreceivers which break of power supply can cause: danger to life of people, significant damage to the national economy; damage of the expensive capital equipment, mass defects of products, disorder of difficult technology process, violation of functioning of especially important elements of municipal services.
  2. From structure of electroreceivers I of category the special group of electroreceivers which smooth operation is necessary for the accident-free stop of production for the purpose of prevention of threat of life of people, explosions, the fires and damage of the expensive capital equipment is allocated.
  3. Category electroreceivers II - electroreceivers which break of power supply leads to the mass nedootpusk of products, mass idle times of workers, mechanisms and industrial transport, violation of normal activity of the significant amount city and villagers.
  4. Category electroreceivers III - all other electroreceivers which are not fitting the definitions of I and II categories.

1.2.18. Electroreceivers I of category have to be provided with the electric power from 2 independent mutually reserving power sources, and the break of their power supply at violation of power supply from one of power sources can be allowed only for the period of automatic recovery of the power supply.

For power supply of special group of electroreceivers I of category the additional power supply from the 3rd independent mutually reserving power source has to be provided.

As the 3rd independent power source for special group of electroreceivers and as the 2nd independent power source for other electroreceivers I of category local power plants, power plants of power supply systems (in particular, tires of generating tension), special units of uninterruptible power, rechargeable batteries, etc. can be used.

If it is impossible to provide with reservation of power supply the necessary continuity of technology process or if reservation of power supply is economically inexpedient, technology reservation, for example, by installation of mutually reserving technology units, special devices of the accident-free stop of technology process operating at power supply violation has to be carried out.

Power supply of electroreceivers I of category with the particularly complex continuous technology process demanding the long time on recovery of the operating duty in the presence of feasibility studies is recommended to carry out from two independent mutually reserving power sources to which the additional requirements determined by features of technology process are imposed.

1.2.19. It is recommended to provide electroreceivers II of category with the electric power from 2 independent mutually reserving power sources.

For category electroreceivers II at violation of power supply from one of power sources power supply breaks for time necessary for inclusion of back supply actions of personnel on duty or mobile operational team are admissible.

The power supply of electroreceivers II of category on one VL, including with the cable insert is allowed if the possibility of carrying out emergency repair of this line during no more than 1 days is provided. Cable inserts of this line have to be carried out by 2 cables, each of which gets out on the greatest long current of VL. The power supply of electroreceivers II of category on one cable line consisting not less than of two cables attached to one general device is allowed.

In the presence of the centralized reserve of transformers and the possibility of replacement of the damaged transformer during no more than 1 days the power supply of electroreceivers II of category from one transformer is allowed.

1.2.20. For category electroreceivers III power supply can be carried out from one power source provided that the power supply breaks necessary for repair or replacement of the damaged utility power system element, do not exceed 1 days.

Levels and voltage regulation, reactive power compensation

1.2.21. For network circuits it is necessary to provide technical actions for ensuring quality of tension of electrical energy according to requirements of GOST 13109-87 "Electrical energy. Requirements to quality of electrical energy in network circuits of general purpose".

1.2.22. Devices of voltage regulation have to provide maintenance of tension on those tires of 6-20 kV of power plants and substations to which distribution networks are attached, within not lower than 105% rated in the period of the greatest loadings and it is not higher than 100% rated in the period of the smallest loadings of these networks.

1.2.23. The devices of reactive power compensation installed at the consumer have to provide consumption from the power supply system of reactive power in the limits specified in conditions accession of electric units of this consumer to the power supply system.

1.2.24. The choice and placement of devices of reactive power compensation in network circuits should be made according to the existing instruction on reactive power compensation.

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