GOST 50571.18-2000 (IEC 60364-4-442-93) UDC 696.6:006.354 Group E08 STATE STANDARD OF THE RUSSIAN FEDERATION Electrical installations of buildings Part 4: Protection for safety Chapter 44 Surge Protection Section 442 PROTECTION OF ELECTRIC TO 1 kV OVERVOLTAGE CAUSED earth fault in electrical ABOVE 1kV Electrical installations of buildings. Part 4. Protection for safety. Chapter 44. Protection against overvoltages. Section 442. Protection of low-voltage installations against faults between high-voltage systems and earth Effective date 01/01/2002 OKS OKS 3402 91.140.50 29.120.50 Preface 1 to develop the All-Russian Research Institute for Electrification of Agriculture (VIESKh) and the All-Russian Research Institute of Standardization and Certification in Engineering (VNIINMASH), introduced by the Technical Committee for Standardization TC 337 "Electrical installations of residential and public buildings" 2 adopted and put into operation the Decree of the State Standard of Russia on Dec. 18, 2000 № 372-Article 3 of this standard is the authentic text of the International IEC 60364-4-442-93 "Electrical installations of buildings. Part 4. Security requirements. Chapter 44. Surge protection. Section 442. Protection of low-voltage installations against high-voltage circuits between systems and the earth "with Amendment number 1 (1995) with additional requirements taking into account the needs of the country's economy was first introduced 4 Enter This standard is part of the state standards for electrical installations of buildings, developed based on the standards of the International Electrotechnical Commission IEC 364 "Electrical installations of buildings." It represents the authentic text of the international standard IEC 60364-4-442-93, except section 1, the qualifying features of this standard in the national energy Section 3, which eliminates ambiguity in the interpretation of terms and requirements (in italics) to reflect the needs of various industries economy, including agricultural production. The numbering of chapters, paragraphs and subparagraphs of this standard, since section 442.1, in full conformity with the IEC 60364-4-442-93 to reflect the number 1 (1995) (introduced new sections 442.6 and 442.7). Table 44A in this standard is replaced by a new one in accordance with Amendment number 1. This standard adopted the same numbering of figures and symbols are the same as in IEC 60364-4-442-93. Requirements of the standard complement, modify or supersede the requirements of other private standards set standards for electrical installations of buildings. The absence of references to the chapter, section or paragraph of the private standard means that the relevant requirements of the standard apply to this case. 1 Scope This standard applies to electrical installations of buildings used in all sectors of the economy, regardless of their affiliation and ownership, and establishes requirements for electrical safety by protecting against surges that can occur in electrical systems up to 1 kV due to earth fault in electrical systems above 1 kV. In this case, electrical up to and above 1 kV can be both electrically connected and unconnected to each other. The term "electrically" is understood as a direct link to joint between a neutral conductive parts of electrical installations of various stresses and by feeding the step-down transformers. Electrically interconnected electrical most often occur in rural areas and are usually independent power supply voltage up to 1 kV, located in the vicinity of overhead power lines installations above 1 kV networks with effectively grounded neutral or near the transformer substations of such facilities. With regard to agricultural production surge protection should provide electrical, not only people but also farm animals, including the removal elektropatologii cattle, ie, decrease in productivity under the influence of a safe and life is quite low voltages touch. It is intended to design, installation, commissioning and maintenance organizations of all forms of ownership. Requirements to complement the IEC 60364-4-442-93 and responsive to the needs of the economy, highlighted in the text of this standard in italics. The requirements of this standard are mandatory. 2 Normative references in this standard references to the following standards: GOST 30331.2-95 (IEC 364-3-93) / GOST 50571.2-94 (IEC 364-3-93) Electrical installations of buildings. Part 3. Key features Standard 30331.3-95 (IEC 364-4-41-92) / GOST 50571.3-94 (IEC 364-4-41-92) Electrical installations of buildings. Part 4. Security requirements. Protection against electric shock GOST 50571.14-96 (IEC 364-7-705-84) Electrical installations of buildings. Part 7. Requirements for special installations. Section 705. Electrical installations of agricultural and livestock premises 3 Definitions In this standard, the following terms. 3.1 Land (relative, reference): conductive and which is outside the zone of influence of any earthing of the earth's crust, the electric potential is assumed to be zero. 3.2 Local land: Part of the land, which is in contact with the grounding, the electric potential is influenced by current flowing from the earthing may be different from zero. In cases where the difference from zero potential of the land does not matter, instead of the term "local land" use the generic term "ground". 3.3 to 1 kV electrical installation: electrical, rated voltage not exceeding 1 kV. 3.4 above 1 kV electrical installation: electrical, rated voltage is equal to or greater than 1 kV. 3.5 Electric Network with effectively grounded neutral: Three-phase power network above 1 kV, in which the coefficient of earth fault does not exceed 1.4. 3.6 coefficient of earth fault: The ratio of the potential difference in the three-phase mains between phase and earth intact at the point of ground fault of another phase or the other two phases to the potential difference between phase and earth at this point to the circuit. 3.7 conductive parts: Part ability to conduct electrical current. 3.8 neutral conductive part (neutral conductor): Part of the electrical installations that can conduct electrical current, the potential for a normal operating condition is equal or close to zero, such as housing the transformer, switchgear cabinet, casing starter wire bonding system, PEN-conductor, etc. Section 3.9 exposed conductive parts: Affordable touch-conductive part is normally not under stress, but which may be energized when the damaged insulation. 10.3 sided conductive parts: conductive part that is not part of the installation. 11.3 conductor: Part is designed to conduct electrical current a certain value. 03.12 live parts: Explorer or conductive parts, designed to work under stress in normal operating mode of the installation. 3.13 groundfault: Accidental or intentional (eg, triggered shorting) the emergence of a conducting connection between a live current carrying parts and ground, or not insulated from the conducting part of the land. 3.14 grounding: Intentional electrical connection to a given point of the system or plant, or equipment to the local earth through the grounding device. 3.15 earthing device: A group of earthing and grounding conductors. 3.16 Earthing: Part of the grounding device, consisting of one or more electrically interconnected grounding electrodes. 3.17 electrically independent earthing (independent earthing): Grounding, located at a distance from other earthing that currents spreading from them have no significant effect on the electrical potential of the independent earthing. 3.18 grounding conductor: The conductor that connects the grounding point of the system or plant, or equipment grounding. 3.19 grounding electrode (earthing electrode): A conductive part which is in electrical contact with the local land, either directly or through an intermediate conductive medium, such as through a layer of concrete or conductive corrosion-resistant coating. 3.20 potentsialovyravnivayuschy electrode: Same as the ground electrode, but used to equalize electrical potential. 3.21 resistance grounding system: The ratio of voltage to the grounding device (relative to the earth) at ground systems or devices or equipment to the current flowing from the earthing to the ground, an equal amount of resistance grounding conductor and spreading resistance earthing. 3.22 earthing resistance spreading (spreading resistance earthing current into the ground): The ratio of stress at a point on the earthing in place of connection of grounding conductor (relative to the ground) to the current flowing from the earthing to the ground. 3.23 equalizing electrical potential: The electrical connection of conductive parts with each other to achieve their equipotential. 3.24 protective equalizing electrical potentials: Equalizing the electric potentials in order to ensure electrical safety through the elimination of electrical potential difference between all simultaneously accessible exposed conductive parts of the touch of a stationary electrical equipment and third-party conductive parts, including metal parts of the building constructions, achieved a reliable connection of these parts with one another through conductors. 3.25 The containment system of equalizing the electrical potential (protective device equalize electrical potential): The set of conductors and their connections to the conductive parts, providing a protective equalizing potentials. 3.26 protective lining of electric potentials: A measure to ensure electrical safety of lowering the relative difference in electrical potential between various points on the surface of the local land or conductive floor (step voltage) between these points and grounding device, or exposed conductive parts (touch voltage) in normal and emergency modes of operation, achieved a compound of the grounding device and the exposed conductive parts stacked in a local ground or floor potentsialovyravnivayuschimi conducting electrodes. 3.27 aligned electric potentials: Same as that defensive alignment, and electrical potentials, but holds not only for electrical safety, but also for other purposes, such as removing harmful (causing interference) stresses in the highly specialized information technology units. 3.28 alignment system of electric potentials (the device alignment of electric potentials, the short UVEP): System, device, ensuring alignment of the electric potentials. 3.29 touch voltage: The voltage between the two exposed conductive parts while touching them with a human or animal, as well as tension between the exposed conductive parts to which touches a person or animal, and place on the surface of the local land or carrying out the floor on which there is a person or animal . 3.30 expected touch voltage: Same as the touch voltage, but the assumption that a person or animal is missing. 3.31 step voltage: The voltage between two points on the surface of the local land or carrying out the gender, situated at a distance of 1 m from each other (with respect to humans) and at a distance of 1,4 m (for cattle), which is regarded as a step length human or as the distance between the front and rear animals. 3.32 voltage ground fault in electrical systems above 1 kV (voltage circuit): The voltage on the earthing system (relative to the earth) at ground electrical installations above 1 kV at the time of ground fault current-carrying parts of electrical installations, the product of resistance grounding system for flowing down the him into the ground current. 3.33 critical stress (prebreakdown voltage): The voltage applied to the electrical insulation of live parts of electrical installations up to 1 kV at the time of ground fault in electrical systems above 1 kV and capable of at certain cause its breakdown. 3.34 allowable critical voltage (rated voltage): The critical stress is taken into account as the basis for the design of electrical installations. 3.35 times of protection against earth fault (ground fault duration, the duration of earth fault trip time): The time period from the date of closure to the ground before the trip device power, ie, until off the damaged section. 3.36 grounding system (grounding system): The sum of the substation grounding devices, exposed conductive parts of the consumer and the neutral conductor in electrical systems up to 1 kV. 3.37 Type of ground: The indicator on the ratio of neutral to ground the transformer in the substation and the exposed conductive parts of the consumer and device neutral conductor. Designation of types of earthing systems - according to GOST R 50571.2 30331.2/GOST. Distinguish TN-, TT-and IT-system, the first two of which are grounded at the transformer substation, and the third - in isolation. TN-system on the device neutral conductor, in turn, is divided into TN-S-, TN-C and TN-CS-system. 3.38 neutral: Intentional electrical connection to a neutral conducting part (neutral conductor) in electrical systems up to 1 kV grounded neutral transformer at the substation. 3.39 neutral conductor (N-conductor): The conductor in electrical systems up to 1 kV, intended for single-phase power and power consumers connected to the grounded transformer at the substation. 3.40 protective conductor (PE-conductor): The conductor in electrical systems up to 1 kV, intended for security purposes and linking the exposed conductive parts of the consumer with a grounding device. 3.41 combined zero-worker and the protective conductor (PEN-conductor): The conductor in electrical systems up to 1 kV, which combines the functions of a zero-worker and protective conductors. 442.1 General provisions 442.1.1 Appointment of The requirements of this standard are intended to ensure electrical safety of people and livestock, as well as the protection of electrical equipment in electrical installations up to 1 kV in case of an earth fault on the side of above 1 kV transformer substation, from which the electrical installation is supplied. 442.1.2 Voltage Voltage circuit ground fault in electrical systems above 1 kV and the ensuing closure of the expected contact voltage between the exposed conductive parts and the local ground in electrical systems up to 1 kV shall not exceed the values ??determined respectively by the curves F and T in Figure 44A for different the response time of protection against earth faults in electrical systems above 1 kV. 442.1.3 Critical stress the critical stresses arising in electrical systems up to 1 kV due to earth faults in electrical systems above 1 kV shall not exceed the values ??shown in Table 44A for different reaction time of protection against earth faults in electrical systems above 1 kV. Notes 1 Critical stress - a power frequency voltage, which affects the electrical insulation of live parts of electrical installations up to 1 kV at the time of ground fault in electrical systems above 1 kV. Two higher values ??of critical stress allowed for electrical up to 1 kV transformer substations in cases where the insulation meets the conditions of 442.3. 3 for the electrical installations of agricultural and livestock buildings should instead use the data table 44A in Table 1, given in GOST R 50571.14. Table 44A Allowable critical voltage electrical equipment up to 1 kV in the turn-off time of 250 St. U0 + U0 + 5 1200 5 Notes 1 In some specific cases, such as when one of the conductors of electrical lines up to 1 kV is connected to the earth, then the greatest stress in this setting may not be equal to U0 and must be found by performing the calculations. 2 The first row of the table applies to electrical installations up to 1 kV electric facilities associated with the above 1 kV low earth fault currents and large response time protection against earth faults, such as those in which the neutral is earthed via a high inductive reactance. The second row of the table applies to electrical installations associated with the electric facilities above 1 kV with high current ground fault and low response time of protection against earth faults, such as electrical installations with a well-grounded. The two rows of the table should be used when designing the electrical up to and above 1 kV to assess the reliability of electrical insulation equipment when calculating the transient surges that can occur when an earth fault. 3 Such temporary surges can occur in electrical systems up to 1 kV in case of placement of TN-systems outside the unit balancing electric potential electrical installations above 1 kV with effectively grounded neutral and should be considered in the design by selecting the electrical equipment with electrical isolation of various levels - primary, double, enhanced (especially when the neutral conductor TN-system is connected to the grounding and electrical devices potentsialovyravnivayuschemu above 1 kV). However, there is no need to determine the voltage on electrical installations up to 1 kV, which is located in electrical systems above 1 kV within a system of equalizing electrical potentials, and a similar system within the building, even if they are linked by neutral conductive parts, such as PEN-conductor TN-system. 442.2 Earthing transformer substations at the transformer substation operates one of the grounding device, which is connected to: - grounding electrodes - grounding wires - potentsialovyravnivayuschie electrodes - the case of transformers - a metal cable armor voltages above 1 kV - metal armor cable with voltage up to 1 kV except those who have a neutral conductor is grounded on an independent earthing - exposed conductive parts of equipment to and above 1 kV - sided conductive parts. Part 1. Chapter 1. Chapter 2. Chapter 3. General specifications GOST 2.702-75 Unified system for design documentation. Rules for making electronic circuits with GOST 2.752-71 Unified system for design documentation. Graphical symbols in diagrams. Robot device GOST 2.755-87 Unified system for design documentation. Graphical symbols in electrical circuits. Device switching and contact connections GOST 2.756-76 * Unified system for design documentation. Graphical symbols in diagrams. Is often perceived electromechanical devices GOST 2.757-81 * Unified system for design documentation. Graphical symbols in diagrams. Elements of the switching field for switching systems GOST 2.758-81 Unified system for design documentation. Graphical symbols in diagrams. Signal Technology GOST 2.762-85 * Unified system for design documentation. Graphical symbols in electrical circuits. Frequencies and frequency bands for transmission systems GOST 2.763-85 * Unified system for design documentation. Graphical symbols in electrical circuits. Device with a pulse-code modulation GOST 2.764-86 Unified system for design documentation. Graphical symbols in electrical circuits. Integrated optoelectronic display elements GOST 2.768-90 Unified system for design documentation. Graphical symbols in diagrams.
GOST 50571.18-2000 (IEC 60364-4-442-93) UDC 696.6:006.354 Group E08 STATE STANDARD OF THE RUSSIAN FEDERATION Electrical installations of buildings Part 4: Protection for safety Chapter 44 Surge Protection Section 442 PROTECTION OF ELECTRIC TO 1 kV OVERVOLTAGE CAUSED earth fault in electrical ABOVE 1kV Electrical installations of buildings. Part 4. Protection for safety. Chapter 44. Protection against overvoltages. Section 442. Protection of low-voltage installations against faults between high-voltage systems and earth Effective date 01/01/2002 OKS OKS 3402 91.140.50 29.120.50 Preface 1 to develop the All-Russian Research Institute for Electrification of Agriculture (VIESKh) and the All-Russian Research Institute of Standardization and Certification in Engineering (VNIINMASH), introduced by the Technical Committee for Standardization TC 337 "Electrical installations of residential and public buildings" 2 adopted and put into operation the Decree of the State Standard of Russia on Dec. 18, 2000 № 372-Article 3 of this standard is the authentic text of the International IEC 60364-4-442-93 "Electrical installations of buildings. Part 4. Security requirements. Chapter 44. Surge protection. Section 442. Protection of low-voltage installations against high-voltage circuits between systems and the earth "with Amendment number 1 (1995) with additional requirements taking into account the needs of the country's economy was first introduced 4 Enter This standard is part of the state standards for electrical installations of buildings, developed based on the standards of the International Electrotechnical Commission IEC 364 "Electrical installations of buildings." It represents the authentic text of the international standard IEC 60364-4-442-93, except section 1, the qualifying features of this standard in the national energy Section 3, which eliminates ambiguity in the interpretation of terms and requirements (in italics) to reflect the needs of various industries economy, including agricultural production. The numbering of chapters, paragraphs and subparagraphs of this standard, since section 442.1, in full conformity with the IEC 60364-4-442-93 to reflect the number 1 (1995) (introduced new sections 442.6 and 442.7). Table 44A in this standard is replaced by a new one in accordance with Amendment number 1. This standard adopted the same numbering of figures and symbols are the same as in IEC 60364-4-442-93. Requirements of the standard complement, modify or supersede the requirements of other private standards set standards for electrical installations of buildings. The absence of references to the chapter, section or paragraph of the private standard means that the relevant requirements of the standard apply to this case. 1 Scope This standard applies to electrical installations of buildings used in all sectors of the economy, regardless of their affiliation and ownership, and establishes requirements for electrical safety by protecting against surges that can occur in electrical systems up to 1 kV due to earth fault in electrical systems above 1 kV. In this case, electrical up to and above 1 kV can be both electrically connected and unconnected to each other. The term "electrically" is understood as a direct link to joint between a neutral conductive parts of electrical installations of various stresses and by feeding the step-down transformers. Electrically interconnected electrical most often occur in rural areas and are usually independent power supply voltage up to 1 kV, located in the vicinity of overhead power lines installations above 1 kV networks with effectively grounded neutral or near the transformer substations of such facilities. With regard to agricultural production surge protection should provide electrical, not only people but also farm animals, including the removal elektropatologii cattle, ie, decrease in productivity under the influence of a safe and life is quite low voltages touch. It is intended to design, installation, commissioning and maintenance organizations of all forms of ownership. Requirements to complement the IEC 60364-4-442-93 and responsive to the needs of the economy, highlighted in the text of this standard in italics. The requirements of this standard are mandatory. 2 Normative references in this standard references to the following standards: GOST 30331.2-95 (IEC 364-3-93) / GOST 50571.2-94 (IEC 364-3-93) Electrical installations of buildings. Part 3. Key features Standard 30331.3-95 (IEC 364-4-41-92) / GOST 50571.3-94 (IEC 364-4-41-92) Electrical installations of buildings. Part 4. Security requirements. Protection against electric shock GOST 50571.14-96 (IEC 364-7-705-84) Electrical installations of buildings. Part 7. Requirements for special installations. Section 705. Electrical installations of agricultural and livestock premises 3 Definitions In this standard, the following terms. 3.1 Land (relative, reference): conductive and which is outside the zone of influence of any earthing of the earth's crust, the electric potential is assumed to be zero. 3.2 Local land: Part of the land, which is in contact with the grounding, the electric potential is influenced by current flowing from the earthing may be different from zero. In cases where the difference from zero potential of the land does not matter, instead of the term "local land" use the generic term "ground". 3.3 to 1 kV electrical installation: electrical, rated voltage not exceeding 1 kV. 3.4 above 1 kV electrical installation: electrical, rated voltage is equal to or greater than 1 kV. 3.5 Electric Network with effectively grounded neutral: Three-phase power network above 1 kV, in which the coefficient of earth fault does not exceed 1.4. 3.6 coefficient of earth fault: The ratio of the potential difference in the three-phase mains between phase and earth intact at the point of ground fault of another phase or the other two phases to the potential difference between phase and earth at this point to the circuit. 3.7 conductive parts: Part ability to conduct electrical current. 3.8 neutral conductive part (neutral conductor): Part of the electrical installations that can conduct electrical current, the potential for a normal operating condition is equal or close to zero, such as housing the transformer, switchgear cabinet, casing starter wire bonding system, PEN-conductor, etc. Section 3.9 exposed conductive parts: Affordable touch-conductive part is normally not under stress, but which may be energized when the damaged insulation. 10.3 sided conductive parts: conductive part that is not part of the installation. 11.3 conductor: Part is designed to conduct electrical current a certain value. 03.12 live parts: Explorer or conductive parts, designed to work under stress in normal operating mode of the installation. 3.13 groundfault: Accidental or intentional (eg, triggered shorting) the emergence of a conducting connection between a live current carrying parts and ground, or not insulated from the conducting part of the land. 3.14 grounding: Intentional electrical connection to a given point of the system or plant, or equipment to the local earth through the grounding device. 3.15 earthing device: A group of earthing and grounding conductors. 3.16 Earthing: Part of the grounding device, consisting of one or more electrically interconnected grounding electrodes. 3.17 electrically independent earthing (independent earthing): Grounding, located at a distance from other earthing that currents spreading from them have no significant effect on the electrical potential of the independent earthing. 3.18 grounding conductor: The conductor that connects the grounding point of the system or plant, or equipment grounding. 3.19 grounding electrode (earthing electrode): A conductive part which is in electrical contact with the local land, either directly or through an intermediate conductive medium, such as through a layer of concrete or conductive corrosion-resistant coating. 3.20 potentsialovyravnivayuschy electrode: Same as the ground electrode, but used to equalize electrical potential. 3.21 resistance grounding system: The ratio of voltage to the grounding device (relative to the earth) at ground systems or devices or equipment to the current flowing from the earthing to the ground, an equal amount of resistance grounding conductor and spreading resistance earthing. 3.22 earthing resistance spreading (spreading resistance earthing current into the ground): The ratio of stress at a point on the earthing in place of connection of grounding conductor (relative to the ground) to the current flowing from the earthing to the ground. 3.23 equalizing electrical potential: The electrical connection of conductive parts with each other to achieve their equipotential. 3.24 protective equalizing electrical potentials: Equalizing the electric potentials in order to ensure electrical safety through the elimination of electrical potential difference between all simultaneously accessible exposed conductive parts of the touch of a stationary electrical equipment and third-party conductive parts, including metal parts of the building constructions, achieved a reliable connection of these parts with one another through conductors. 3.25 The containment system of equalizing the electrical potential (protective device equalize electrical potential): The set of conductors and their connections to the conductive parts, providing a protective equalizing potentials. 3.26 protective lining of electric potentials: A measure to ensure electrical safety of lowering the relative difference in electrical potential between various points on the surface of the local land or conductive floor (step voltage) between these points and grounding device, or exposed conductive parts (touch voltage) in normal and emergency modes of operation, achieved a compound of the grounding device and the exposed conductive parts stacked in a local ground or floor potentsialovyravnivayuschimi conducting electrodes. 3.27 aligned electric potentials: Same as that defensive alignment, and electrical potentials, but holds not only for electrical safety, but also for other purposes, such as removing harmful (causing interference) stresses in the highly specialized information technology units. 3.28 alignment system of electric potentials (the device alignment of electric potentials, the short UVEP): System, device, ensuring alignment of the electric potentials. 3.29 touch voltage: The voltage between the two exposed conductive parts while touching them with a human or animal, as well as tension between the exposed conductive parts to which touches a person or animal, and place on the surface of the local land or carrying out the floor on which there is a person or animal . 3.30 expected touch voltage: Same as the touch voltage, but the assumption that a person or animal is missing. 3.31 step voltage: The voltage between two points on the surface of the local land or carrying out the gender, situated at a distance of 1 m from each other (with respect to humans) and at a distance of 1,4 m (for cattle), which is regarded as a step length human or as the distance between the front and rear animals. 3.32 voltage ground fault in electrical systems above 1 kV (voltage circuit): The voltage on the earthing system (relative to the earth) at ground electrical installations above 1 kV at the time of ground fault current-carrying parts of electrical installations, the product of resistance grounding system for flowing down the him into the ground current. 3.33 critical stress (prebreakdown voltage): The voltage applied to the electrical insulation of live parts of electrical installations up to 1 kV at the time of ground fault in electrical systems above 1 kV and capable of at certain cause its breakdown. 3.34 allowable critical voltage (rated voltage): The critical stress is taken into account as the basis for the design of electrical installations. 3.35 times of protection against earth fault (ground fault duration, the duration of earth fault trip time): The time period from the date of closure to the ground before the trip device power, ie, until off the damaged section. 3.36 grounding system (grounding system): The sum of the substation grounding devices, exposed conductive parts of the consumer and the neutral conductor in electrical systems up to 1 kV. 3.37 Type of ground: The indicator on the ratio of neutral to ground the transformer in the substation and the exposed conductive parts of the consumer and device neutral conductor. Designation of types of earthing systems - according to GOST R 50571.2 30331.2/GOST. Distinguish TN-, TT-and IT-system, the first two of which are grounded at the transformer substation, and the third - in isolation. TN-system on the device neutral conductor, in turn, is divided into TN-S-, TN-C and TN-CS-system. 3.38 neutral: Intentional electrical connection to a neutral conducting part (neutral conductor) in electrical systems up to 1 kV grounded neutral transformer at the substation. 3.39 neutral conductor (N-conductor): The conductor in electrical systems up to 1 kV, intended for single-phase power and power consumers connected to the grounded transformer at the substation. 3.40 protective conductor (PE-conductor): The conductor in electrical systems up to 1 kV, intended for security purposes and linking the exposed conductive parts of the consumer with a grounding device. 3.41 combined zero-worker and the protective conductor (PEN-conductor): The conductor in electrical systems up to 1 kV, which combines the functions of a zero-worker and protective conductors. 442.1 General provisions 442.1.1 Appointment of The requirements of this standard are intended to ensure electrical safety of people and livestock, as well as the protection of electrical equipment in electrical installations up to 1 kV in case of an earth fault on the side of above 1 kV transformer substation, from which the electrical installation is supplied. 442.1.2 Voltage Voltage circuit ground fault in electrical systems above 1 kV and the ensuing closure of the expected contact voltage between the exposed conductive parts and the local ground in electrical systems up to 1 kV shall not exceed the values ??determined respectively by the curves F and T in Figure 44A for different the response time of protection against earth faults in electrical systems above 1 kV. 442.1.3 Critical stress the critical stresses arising in electrical systems up to 1 kV due to earth faults in electrical systems above 1 kV shall not exceed the values ??shown in Table 44A for different reaction time of protection against earth faults in electrical systems above 1 kV. Notes 1 Critical stress - a power frequency voltage, which affects the electrical insulation of live parts of electrical installations up to 1 kV at the time of ground fault in electrical systems above 1 kV. Two higher values ??of critical stress allowed for electrical up to 1 kV transformer substations in cases where the insulation meets the conditions of 442.3. 3 for the electrical installations of agricultural and livestock buildings should instead use the data table 44A in Table 1, given in GOST R 50571.14. Table 44A Allowable critical voltage electrical equipment up to 1 kV in the turn-off time of 250 St. U0 + U0 + 5 1200 5 Notes 1 In some specific cases, such as when one of the conductors of electrical lines up to 1 kV is connected to the earth, then the greatest stress in this setting may not be equal to U0 and must be found by performing the calculations. 2 The first row of the table applies to electrical installations up to 1 kV electric facilities associated with the above 1 kV low earth fault currents and large response time protection against earth faults, such as those in which the neutral is earthed via a high inductive reactance. The second row of the table applies to electrical installations associated with the electric facilities above 1 kV with high current ground fault and low response time of protection against earth faults, such as electrical installations with a well-grounded. The two rows of the table should be used when designing the electrical up to and above 1 kV to assess the reliability of electrical insulation equipment when calculating the transient surges that can occur when an earth fault. 3 Such temporary surges can occur in electrical systems up to 1 kV in case of placement of TN-systems outside the unit balancing electric potential electrical installations above 1 kV with effectively grounded neutral and should be considered in the design by selecting the electrical equipment with electrical isolation of various levels - primary, double, enhanced (especially when the neutral conductor TN-system is connected to the grounding and electrical devices potentsialovyravnivayuschemu above 1 kV). However, there is no need to determine the voltage on electrical installations up to 1 kV, which is located in electrical systems above 1 kV within a system of equalizing electrical potentials, and a similar system within the building, even if they are linked by neutral conductive parts, such as PEN-conductor TN-system. 442.2 Earthing transformer substations at the transformer substation operates one of the grounding device, which is connected to: - grounding electrodes - grounding wires - potentsialovyravnivayuschie electrodes - the case of transformers - a metal cable armor voltages above 1 kV - metal armor cable with voltage up to 1 kV except those who have a neutral conductor is grounded on an independent earthing - exposed conductive parts of equipment to and above 1 kV - sided conductive parts. 442.3 Requirements for the grounding devices of transmission substations was generally accepted that the requirements listed in 442.4 and 442.5, will be automatically made for substations with small currents, ground fault, if there is at least one of the conditions of 442.3.1 and 442.3.2. If none of these conditions is not satisfied, you must follow the requirements of 442.4 and 442.5. With regard to electric agricultural and pastoral areas, especially when it comes to providing Electrical farm animals, which compared with a person more sensitive to electric current, it is necessary to take into account the conditions laid down in GOST R 50571.14. 442.3.1 The conditions considered for grounding devices From the standpoint of the requirements for the grounding devices of transmission substations, should consider the following options for the waste from a substation cable lines that affect the overall resistance of substation grounding system: - a single cable voltages above 1 kV, length less than 1 km, metallic armor is attached to a transformer substation earthing system - the same voltage to 1 kV - a few cables the same or different voltages (up to and above 1 kV), the metal shell which are attached to the earthing system of the transformer substation, subject to that their overall length is less than 1 km. 442.3.2 resistance grounding system to fulfill the requirements 442.4 and 442.5 is influenced by various conditions, one of which is the natural resistance of earthing exposed conductive parts of the transformer substation that does not exceed 1 ohm. 442.4 Requirements for the grounding devices of transmission substations, taking into account the types of grounding systems used 442.4.1 Symbols In this standard, the following symbols: Im - part of the earth fault currents in electrical systems above 1 kV, which flows through the grounding device is exposed conductive parts transformer substation; Id - part of earth fault current, which flows through the grounding device is exposed conductive parts of electrical installations up to 1 kW of electricity at the consumer; R - resistance of the grounding device exposed conductive parts of the transformer substation, RA - the resistance of the grounding device exposed conductive parts of electrical installations up to 1 kV a consumer of electricity; RB - resistance to an independent grounding device; Z - Impedance (Impedance) resistors or other elements that connect through the neutral of the transformer to the earthing system; U0 - phase voltage between the wires and neutral electrical up to 1 kV; U - voltage between two electrical phase conductors up to 1 kV (line voltage); Uf - voltage in electrical systems up to 1 kV between exposed conductive parts and earth (the expected voltage touching) a consumer of electricity that occurs when earth fault in electrical systems above 1 kV; U1 - the critical stress in equipment with voltage up to 1 kV transformer substation; U2 - the critical voltage for equipment with voltage up to 1 kW of electricity at the consumer; UL - the maximum expected voltage touching the exposed conductive parts of electrical installations up to 1 kV, a consumer of electricity. 442.4.2 TN-systems a) In cases where the voltage circuit R s Im lies in the time limits specified in Figure 44A, the neutral conductor of electrical installations up to 1 kV power consumer can be connected to the earthing system exposed conductive parts of the transformer substation (see TN -a in Figure 44c). Note-If the exposed conductive parts of electrical installations up to 1 kW of electricity consumers are in the area of ??the equalization system of electric potentials, the expected touch voltage will be close to zero (see Section 413 30331.3/GOST GOST R 50571.3). b) If the condition of subparagraph a) is not satisfied, the neutral conductor of electrical installations up to 1 kV power consumer must be grounded by electrically independent earthing (see TN-b in Figure 44c). In this case, apply the rules of section 442.5.1. 442.4.3 CT system a) If the voltage of R x Im an earth fault on the side of above 1 kV and duration of this closure correspond to the requirements of Table 44A, the neutral conductor of electrical installations up to 1 kV can be attached to the grounding device exposed conductive parts of the transformer substation (see TT-44S and in the figure). b) In the case where the condition of subparagraph a) is not satisfied, the neutral conductor of electrical installations up to 1 kV must be grounded on an electrically independent earthing (see CT-b in Figure 44S). In this case, apply the rules of section 442.5.1. If the exposed conductive parts of electrical installations up to 1 kW of electricity consumers are in the area of ??the equalization system of electric potentials of the transformer substation, the expected touch voltage to those exposed conductive parts of people standing on the ground close to zero. 442.4.4 IT-systems a) When the voltage circuit R s Im, off for the time shown in Figure 44A, exposed conductive parts of electrical installations up to 1 kV power consumer can be connected to the grounding device exposed conductive parts of the substation (see Figures 44D, 44J and 44K). If this condition is not fulfilled, the exposed conductive parts of electrical installations up to 1 kV consumers of electricity should be connected to the grounding device is electrically independent of the grounding device exposed conductive parts of the transformer substation (see Figures 44E-44N), or the consumer must be satisfied UVEP. b) If the exposed conductive parts of electrical installations up to 1 kV power consumer grounded through the grounding device is electrically independent of the grounding system of the transformer substation, and when the ratio between the critical stress (R ? Im + U0) and time off, the data in Table 44A, appropriate equipment electrical installations up to 1 kV power consumer, the total resistance (impedance) system neutral low voltage can be connected to the grounding device exposed conductive parts of the transformer substation (see Figure 44E). If not satisfied this condition, the impedance neutral must be connected through an electrically independent earthing (see Figures 44F and 44N). In this case, apply the rules 442.5.2. 442.5 Limitation critical voltage for equipment up to 1 kV transformer substation 442.5.1 TN-and TT-systems if a system of TN and TT neutral conductor grounded through the grounding device is electrically independent of the grounding device exposed conductive parts of the transformer substation (see TN-b on Figure 44c and CT-b in Figure 44S), the critical stress (R ? Im + U0) should be switched off for a time, depending on the insulation level of equipment with voltage up to 1 kV transformer substation. Note-The isolation level of equipment with voltage up to 1 kV transformer substation may be higher than indicated in Table 44A. 442.5.2 IT-system If the IT-system exposed conductive parts of the installation of the consumer and resistors in the neutral, if any, are grounded through the grounding device is electrically independent of the grounding system of the transformer substation (see Figures 44F, 44G and 44N), the critical stress (R ? Im + U0) should be switched off for a time, depending on the insulation level of equipment with voltage up to 1 kV transformer substation. Note - The level of equipment insulation voltage up to 1 kV transformer substation may be higher than indicated in Table 44A. 442.5.2 IT-system If the IT-system exposed conductive parts of the installation of the consumer and resistors in the neutral, if any, are grounded through the grounding device is electrically independent of the grounding devices of the transformer substation (see Figures 44F, 44G and 44H), critical stress (R ? Im + U0) should be switched off for a time, depending on the insulation level of equipment with voltage up to 1 kV transformer substation. 442.6 The critical stress in case of breakage of the neutral conductor in TN-and TT-systems when designing electrical installations should be considered possible cases of breakage of the neutral conductor in three-phase TN-and TT-systems, and the choice of electrical equipment and its components with the basic, double and reinforced electrical isolation should Note, if breakage of the neutral conductor for electrical insulation to act did not phase and line voltage, which is just above the phase. 442.7 Critical stresses in the case of an earth fault in the IT-system at run time calculations must be considered possible cases of an earth fault of one of the three-phase wires IT-systems, and the choice of electrical equipment and its components with the basic, double and reinforced electrical isolation in mind that when such an earth fault in the insulation will act no longer phase and line voltage, which is just above the phase. Figure 44A - the voltage circuit (curve F) and the expected touch voltage (curve T) of the maximum duration of an earth fault on the side of above 1 kV Figure 44c - TN-system Figure 44S - TT-system 1) The installation of up to 1 kV circuit is not 2) The first circuit in the installation of up to 1 kV Figure 44D - IT-system, an example of a) 1) In the installation of up to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44E - IT-system, an example of b) 1) set to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44F - ITsistemy, sample C1) 1) install up to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44G - IT-system, an example of c2 ) 1) In the installation of up to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44N - IT-system, an example d) 1) The installation of up to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44J - IT-systems, an example E1) 1) install up to 1 kV circuit no 2) The first circuit in the installation of up to 1 kV Figure 44K - IT-system, an example of e2) Annex A (informative) Notes on section 442.1 and paragraphs 442.1.2 , 442.1.3 A.442.1 General Requirements of this section are aimed at ensuring people's safety and protection equipment in electrical installations up to 1 kV in case of a ground fault in electrical systems above 1 kV. Circuit between the electric installations up to and above 1 kV can occur at transformer substations and switching devices operating at voltages above 1 kV. In such circuits the current flows through the grounding device is connected to all exposed conductive parts of the substation. The value of earth fault current depends on the total resistance (impedance) of neutral grounding, ie, on how the grounded neutral electrical installations above 1 kV (effective grounding or earthing through the arcing coil). Fault current flowing through the grounding device is exposed conductive parts of the transformer substation, causes the electrical potential on these parts in relation to the earth, and its value depends on two factors: - the value of the fault current - values ??of earth resistance exposed conductive parts of the substation. Circuit voltage can reach several thousand volts, depending on the electrical grounding system can cause: - an overall increase relative to the ground electric potential of grounding electrical systems up to 1 kV, which can cause breakdown of electrical insulation equipment and thereby damage it - an increase relative to the ground electric potential of exposed conductive parts of electrical installations up to 1 kV, which can cause dangerous touch voltage expected. It should be remembered that for the Elimination of ground fault in electrical systems above 1 kV requires a relatively longer time than in electrical systems up to 1 kV circuits on the case, since the relay protection devices are configured to shut down so that there was some "delay" for automatic detection of undesirable transients. In addition, a proper response time of the protective devices in electrical installations above 1 kV as compared with the response time of protection in electrical systems up to 1 kV. This means that the resulting duration of the voltage circuit to the ground and the expected duration of the touch voltage to exposed conductive parts of electrical installations up to 1 kV can be longer than the time set rules for these installations. Overvoltage caused by ground fault in electrical systems above 1 kV, can lead to malfunctioning transformer substation on the side of up to 1 kV or malfunctioning of electrical installations up to 1 kV power consumer. Indicated failures usually occur when malfunction protection in short-term surges and often lead to various kinds of failures, and even to completely disconnect the electrical installation. Next, we consider the cases ground faults in electrical systems above 1 kV. Effective neutral grounding electrical installations above 1 kV in electrical systems with effectively grounded neutral, neutral transformers connected to a grounding device, either directly or through devices with low total resistance (impedance) in these earth faults are eliminated over a relatively short time thanks to a clear work devices for protection from ground faults . By operating in Russia under the rules for Electrical Power Grid with effectively grounded neutral understand the three-phase power network above 1 kV, in which the coefficient of earth fault does not exceed 1.4. The coefficient of earth fault - it's ratio of the difference in electrical potential in three-phase mains between phase and earth intact at the point of earth fault or the other of the other two phases to the potential difference between phase and earth at this point to ground fault. Transformer substation, where a neutral transformers are not connected to the ground, not considered in the framework of electrical effectively grounded. Capacitive currents in the earth fault in the electrical systems in the calculation are not taken. Electrical installations above 1 kV isolated neutral This standard deals only with cases of the first circuit on the side of the above 1 kV substation to connect to the grounding device exposed conductive parts. Arising in this case capacitive current can be switched off or disconnected depending on the value of this current and setting protective devices. If the circuit is not followed, then a fallback will continue indefinitely. Electrical arcing above 1kVs coils When considering the earth-fault on the side of above 1 kV transformer substation arcing coil shall not be considered. If in electrical systems above 1 kV arcing coil circuit at the transformer substation on the side of a voltage above 1 kV is connected to the grounding device substation exposed conductive parts, arising under this earth fault current is usually negligible (the constant component of this current usually does not exceed tenths of Amperes). These currents can be quite a long time. A.442.1.2 voltage circuit Figure 44A was obtained on the basis of the curve C1 IEC 479-1 [1]. Part 1. Chapter 1. Chapter 2. Chapter 3. General specifications GOST 2.702-75 Unified system for design documentation. Rules for making electronic circuits with GOST 2.752-71 Unified system for design documentation. Graphical symbols in diagrams. Robot device GOST 2.755-87 Unified system for design documentation. Graphical symbols in electrical circuits. Device switching and contact connections GOST 2.756-76 * Unified system for design documentation. Graphical symbols in diagrams. Is often perceived electromechanical devices GOST 2.757-81 * Unified system for design documentation. Graphical symbols in diagrams. Elements of the switching field for switching systems GOST 2.758-81 Unified system for design documentation. Graphical symbols in diagrams. Signal Technology GOST 2.762-85 * Unified system for design documentation. Graphical symbols in electrical circuits. Frequencies and frequency bands for transmission systems GOST 2.763-85 * Unified system for design documentation. Graphical symbols in electrical circuits. Device with a pulse-code modulation GOST 2.764-86 Unified system for design documentation. Graphical symbols in electrical circuits. Integrated optoelectronic display elements GOST 2.768-90 Unified system for design documentation. Graphical symbols in diagrams.
No comments:
Post a Comment