Some standard content:
GB/T 14598.15--1998
This standard is formulated according to the arrangement of the Machinery Industry Science and Technology Development Plan (Standard Formulation and Revision Part) & Electric Thermal Relays. The format and rules of the standardization are based on GB/T 1.1-1993 Guidelines for Standardization Unit 1 Rules for Drafting and Presentation of Standards Part 1: Basic Provisions for Standardization. Since the establishment of the project in March 1997, the publication of IEC 255-8:1990 has been analyzed and studied, especially the cold curve, hot curve and formula in IEC255-8.1990 have been fully demonstrated, which conforms to the current situation in my country and can be equivalent to my country's national standard.
This standard is equivalent to IEC255-8:1990 (electrical heating relays. The national standards of my country cited in this standard are: GB/T 2900.17-1994 Electrical T Terminology Chapter 446 Electrical Relays)
Electrical Relays (eIEC50 (446): 1983, International Electrotechnical Dictionary (1FV) Chapter GB/T 14047-1993
3 Measuring Relays and Protection Devices (idtIEC255-6; 1988) Appendix A, Appendix B and Appendix C of this standard are all appendices of the standard. This standard was proposed by the Ministry of Machinery Industry.
This standard is under the jurisdiction of the National Technical Committee for Standardization of Measuring Relays and Protection Equipment. The drafting unit of this standard: Xuchang Relay Research Institute. The drafters of this standard: Liu Wen, Chu, Zhu Changan, Bai Juhua. GB/T 14598 15—1998
IEC Foreword
1 Formal IEC discussions or agreements on technical issues, drawn up by technical committees with the participation of all national committees particularly concerned with the issue, express, as far as possible, the international consensus on the issues involved. 2) These decisions and agreements are made available for international use in the form of recommended standards and are recognized by the national committees in this sense. 3) In order to promote international consensus, the IEC hopes that the national committees will adopt the contents of the IEC recommended standards as their own national standards to the extent permitted by their national conditions. Any inconsistency between the IEC recommended standards and the corresponding national regulations should be clearly indicated in the national regulations as far as possible.
This standard was prepared by Subcommittee 41B (Measuring relays and protection devices) of Technical Committee 41 (Electrical relays). This standard is the second edition of TEC publication 255-8. It replaces the first edition (1978) and replaces the old IEC publication 255-17, first edition (1982) and second edition (1987). The content of this standard is based on the following documents: Six-month legal document
4113 (Central Office) 47
Voting report
41B (Central Office) 51
Details of the voting for this standard can be seen in the voting report indicated in the table above. This standard is a third-level technical specification.
This standard references the following IEC publications.
Publication:
50: International Electrotechnical Code (IEC 6001-1EV)
255: Electrical relays
255-6 (1988): Part 6: Measuring relays and protection devices 1 Scope and purpose
National Standard of the People's Republic of China
Electrical relays
Part 8: Thermal electrical relays
Elcctrical relays
Part 8: Thermal electrical relaysGB/T14598.15-1998
idt IEC 255-8:1990
This standard applies to time-limited electrical relays, which protect the equipment from electrical and thermal damage by measuring the current flowing through the equipment.
1. 1 This standard includes the following two types of relays: a) electrothermal relays with full memory of the load current state before the relay is switched; b) electrothermal relays with partial memory, such as electrothermal relays with memory only for overload current state. 1.2 This standard also includes special requirements for electrothermal relays used for motor protection. The purpose of this standard is to specify special requirements for electrothermal relays. This standard should be used in conjunction with the first level documents of the TEC:255 series. 2 Definitions
For general terms not defined in this standard, please refer to GB/T2900.171994 (eqV International Electrotechnical Code (IEV) _IEC50J) and higher level documents. The following definitions apply to this standard. 2.1 Hot curve
For electrothermal relays with full memory, a characteristic curve that shows the relationship between the specified operating time and current, taking into account the thermal effect of the specified steady-state negative current before the overload occurs. 2.2 Cold curve
For an electrothermal relay, a characteristic curve that represents the relationship between the specified operating time and the current when the relay is in the reference and steady-state condition of no-load current before the overload occurs. 2.3 Correction (compensation quantity) The amount of correction of the specified characteristic of the relay in a specified manner. This quantity can be the oil temperature, etc. 2.4 Basic current basic current
The specified current limit required for the relay not to operate. Note: The basic current is used as the reference for defining the characteristics of the electrothermal relay. The setting value of the electrothermal relay is expressed as a multiple of this current. 2.5 Constant constant table
The current value related to the minimum operating current accuracy is obtained by multiplying the basic current by this constant. 2.6 Previous load ratio previous load ratio The ratio of the load current to the basic current under specified conditions before the overload. 3 Standard values
3.1 Characteristic curve
Approved by the State Administration of Quality and Technical Supervision on December 21, 1998, and implemented on October 1, 1999
GB/T 14598.15-1998
The time-to-current characteristic can be expressed by equation or by graphical method. Simple thermal model equations are given in 3.1.1 and 3.1.2. Other characteristic curves are allowed and should be specified by the manufacturer. For examples, see Appendix A (Standard Appendix). Note
1 In actual application, such as experiments, it is convenient to give the characteristic curve between current and time. 2 The time constant used in the equation shall be specified by the standard or the manufacturer. 3.1.1 Cold state curve
General curve based on thermal effect and time constant of electric thermal relay. The following formula is given: F2
t = t+Inp - (k. /)
Wu Zhong: · Action time
Time constant!
-Basic current:
-a constant,
Relay current.
3.1.2 Hot curve
Cold curve
The hot curve is related to the preheating of the relay with full memory function. For example, the equation obtained by collecting the general cold curve is given by the following formula, which is derived in Appendix B: t-tmf-(he)
Where: I—load current before overload. 3.2 Nominal range of auxiliary excitation quantity
Nominal ranges other than the preferred range of 80% to 110% in the nominal range shall be specified by the manufacturer. 3.3 Standard reference values of influencing quantities and influencing factors The standard reference values of influencing quantities and influencing factors and the test allowable errors, original current values and correction errors are given in Table 1, Table 2 and Table 3 respectively. GB/T 14598-15-1998 Table 1. Reference conditions and test allowable errors of influencing quantities and influencing factors Influencing quantities and influencing factors General conditions Setting value of basic current Characteristic quantity and Input microexcitation Auxiliary avoidance quantity (reference quantity for determining variation) Reference conditions (see note) Specified by the manufacturer Rated current or specified by the manufacturer Specified by the manufacturer Test allowable error 2\ in any direction,For static relays, the manufacturer specifies
Specified by the manufacturer
According to national standards or specified by the manufacturer
For motor protection, two times and six times the basic current motor protection is: ±1%
DC transient component in AC zero
Setting value
Setting parameters of the curve
DC component in AC
Specified by the manufacturer
Specified by the manufacturer
Rated value
2% of the peak value
Specified by the manufacturer
Specified by the manufacturer
2% of the peak value
Note: Under special conditions of use or when the relay characteristics require the use of non-standard values, the manufacturer should specify the reference value and allowable error. For example, special applications may require 40 ℃ instead of 20 ℃ as the reference value of the ambient temperature. Table 2 Original current value when measuring the effect of influencing quantity Influence quantity
Before overload occurs
Specified load ratio Original load ratio of electro-hydraulic
Motor protection
Standard conditions
For cold curve: zero
For hot curve: specified by the manufacturer
For hot curve: 1.0 or 0.9, selected by the manufacturer
Not applicable Www.bzxZ.net
Test tolerance
Specified by the manufacturer
Standard reference conditions and test tolerance of correction quantity when measuring the effect of influencing quantity Calibration plate
Unbalanced current of multiphase system
Speed of rotating motor to be protected
Temperature of different parts of the protection equipment
(see Note 1)
Temperature of cooling medium of the protected equipment
Reference conditions
Specified by the manufacturer | |tt||For motor protection, the rated speed of the motor is 20℃, or as specified by the manufacturer (see Note 2) Test tolerance
GB/T14047-1993
(idlIEC255-6:1988) Table 2 Note 2
Specified by the manufacturer
1 These correction values represent the thermal steady state of the protected equipment before the overload occurs. Their use depends on the principle of the protection used. 2 When a cooling medium other than air is used, it is mainly specified by the manufacturer. 3.4 Standard limit values of the nominal range of influencing factors and influencing factors The standard limit values of the nominal range of influencing factors and influencing factors, the original current value and the correction value are given in Table 4, Table 5 and Table 6 respectively. - General conditions
Characteristic gain and
Micro-injection
Auxiliary excitation benefit
GB/T 14598 .15-1998
4 Standard limit values of nominal ranges for influencing quantities and influencing factors Influencing quantities and influencing factors
Changes in ambient humidity
Relative humidity
External acidity
Current transients
DC transients in AC (see note)
Setting value
Setting parameters of the circuit
Specified by the manufacturer
Nominal range
5°C in either direction, for static relays, specified by the manufacturerSpecified by the manufacturer
Specified by the manufacturer
Limit of setting range
Specified by manufacturer
60% to 110% of rated value
Specified by manufacturer
Note: If the influence is significant, the manufacturer shall specify the influence of transient current in AC to DC Table 5 Standard limit of nominal range of original current value
Specified load current before overload occurs
Nominal range
0% to 100% of basic current
For motor protection, the influence of original load current is expressed as a ratio, which is the ratio of source load current to basic current. For the characteristic curve of the booster, the ratio shall be selected from the following values, with the underlined values taking precedence: 1.0, 0.9, 0.8, 0.7. 0.6. Table 6 Standard limits for the nominal range of the calibration display
Unbalanced current in a sinusoidal multiphase system (see Notes 1 and 2) Speed of the motor to be protected
Overshoot of the small part of the equipment to be protected
Overshoot of the cooling medium of the equipment to be protected
Nominal range
Because the response of the relay to the calibration range varies greatly, it is impossible to specify it. Instead, the manufacturer specifies
This includes the influence of the overshoot between the phases of the specified multiphase system (if any). 1
| 2 If necessary, the degree of unbalanced current can be specified according to the phase sequence. 3.5
Constant table
There is no standard value for this constant, which shall be specified by the manufacturer. For motor protection, it shall be selected within the range of 1.0 to 1.2 and specified by the manufacturer. 3.6 Setting range of basic current
There is no standard setting range for basic current, which shall be specified by the manufacturer. For motor protection, it shall include the range of 0.8 to 1.1 times the rated current.
3.7 Exit time
There is no standard value for the exit time, which shall be specified by the manufacturer. For relays with partial memory function, in the case of failure to meet the action conditions, in addition to the exit time, the recovery time may also be taken into account. In this case, the manufacturer's specifications shall be issued. 4 Accuracy
4.1 Accuracy of relevant time
4.1.1 Effective range of operating current
GB/T 14598.15:1998
The effective range of operating current shall be specified by the manufacturer, and the upper and lower limits of the effective range shall be expressed in multiples of the basic current value. For motor protection, the standard range shall be 1.25k·IzIB. 4.1.2 Specified operating time
The reference limit error of the specified operating time shall be specified by the manufacturer, and within its effective range, it may be multiplied by the coefficient corresponding to each current value. The reference limit error may be specified by one of the following methods: a) by graphical method
b) by a given error selected from the grade index range, see Appendix C (standardized appendix) C1. For F motor protection, the current values of the following pairs are multiples of the basic current, and the reference error values of the time are expressed in multiples of the relevant time grade index, see Table 7.
Table 7 Relationship between excitation quantity and time error
Multiples of basic current
Multiples of grade index of relevant time
1.25 tons (see note)
Note: Since the influence on the action time is relatively large within this range, the constant is only important for the minimum value of the basic current 4.1.3 Influence of original current and correction quantity on the proposed time limit 6
For the cold curve, the initial current is the rate; for the hot curve, the initial current value should be specified by the manufacturer. For the hot curve of motor protection, the original current should be selected according to Table 5, and the correction value (if any) should be specified by the manufacturer. 4-2 Accuracy of relevant action current
4.2.1 Given error
For electric thermal relays, the given error between the measuring panel action value and the times the basic current value should be selected by the manufacturer from the grade index of the first-level file. For motor protection, the grade index of 20% is not selected. Examples are shown in Appendix (C2 Given in. 4.2.2 The effect of the change in the correction amount on the current
shall be specified by the manufacturer.
5 Tests on action characteristics and accuracy
5.1 General
When conducting tests to determine the error of the relevant time or input excitation current, the conditions specified in Chapter 13 of GB/T14047-1993 shall be followed.
5.2 Measurement of the error of the input excitation current 5.2.1 Measurement of the minimum action current
In order to measure the minimum action current, the input current value shall be lower than the value specified by the manufacturer by 2·Iε (1--grade index/100). Relative to the required accuracy, the current shall be increased step by step with small steps until the relay operates. For the action characteristics, there shall be enough time between each increase. time to allow for a certain accumulation (where appropriate), the setting of the relay operating time (if any) should be at its reference value. 5.2.2 Influence on minimum operating current
The variation of the minimum operating current due to influencing quantities and influencing factors shall be measured in accordance with 5.2.1. When the time or current setting value is an influencing factor, the variation shall be determined at at least two setting points specified by the manufacturer. 5.2.3 Current variation due to current circuit connection In special cases, there may be variations caused by different external electrical circuit connections to the same relay, such as changing three phases to two phases. If feasible, the manufacturer shall specify the effect on the minimum operating current of the relay. 5.3 Determination of the error in the specified time limit
5.3.1 Determination of the cold curve
GB/T 14598.151998
Figure 1 is an example of a test circuit for determining the cold state curve. Test conditions: The input current should change suddenly from zero to an appropriate decimal point of Is. The relay should be allowed sufficient time to return to its initial state before the current is reapplied.
5.3.2 Determining the hot state curve
Figure 2 is an example of a test circuit for determining the hot state curve of a relay with full memory function. Test conditions: The relay should be energized with a current corresponding to the "original load ratio" for a certain time specified by the manufacturer so that the relay reaches thermal equilibrium at this point, and then the basic current I should be de-energized with an appropriate current. Before the next test is carried out, the relay should be allowed to return and stabilize at the original load current for a sufficient time specified by the manufacturer. 5.3.3 Influence of operating time at 21z and 6Zg (for motor protection only) At 21 and 6I, the variation of the operating time caused by the influencing quantity and influencing factor should be determined according to 5.2.1 and 5.2.2. 5.3.4 Time variation due to current circuit connection In special cases, there may be variations caused by different external current circuit connections to the same relay, such as three phases becoming two phases. If practicable, the manufacturer shall specify the effect on the specified operating time of the relay. 6 Thermal performance requirements test
6.1 Limit heat resistance test of relay operating time (for motor protection only) Each input excitation current circuit of the relay shall withstand a secondary current of 121z applied within its own operating time. Current value (or the maximum value specified by the manufacturer).
The setting values of current and time should be the maximum values. After the test, restore under the reference conditions and the relay should meet all technical specifications.
The setting values of current and time should be the maximum values. After the test, restore under the reference conditions and the relay should meet all technical specifications.
Three-phase positive power supply
Contactor head
Figure 1 Test circuit for determining minimum operating current and cold state curve Stop positive
Three-phase voltage power supply
Original load
Contactor power supply
C1 - 1
GB/T14598.15—1998
c2 - 1
C2 - 3
1 S1 controls contactor C2. Set the original load ratio case. C
2 S2 controls contactor C1, and by disconnecting contactor C1-5, C2 returns. And set the multiple conditions of I. Figure 2 Test circuit for determining the hot state curve
C1 - 4
GB/T 14598.15-1998
Appendix A
(Standard Appendix)
Characteristic Curve Cold Curve
Characteristic curves other than the general curves are allowed, which are generally based on thermal effects and time constants (see 3.1.1). Other characteristic curves should be specified by the manufacturer.
For example, if short-term heat dissipation is ignored, the characteristic curve can be based on the equation: t
For currents greater than 18: This equation is correct. This characteristic is suitable for relays with partial memory functions. kIp
Note: In actual use, considering the heat dissipation, the time and current characteristics are (the common constant is specified by the manufacturer) Appendix B
(Standard Appendix)
Characteristic Curve Hot Curve
B1 Considering the thermal simulation temperature, the correction value of the general cold curve (see 3.1.1) can be obtained. I
[k· Ta!
t=r- In
where: — steady-state temperature of load current 1 before overload; , — corresponds to the temperature of · I.
Since:
the above formula can be written as:
GB/T14598.15—1998
B2 The manufacturer can publish the following thermal balance curve with the original load ratio as a parameter. Load current before overload
Basic current
GB/T14598.15—1998
Appendix C
(Appendix of the standard)
Example of determining accuracy
The level index of the relevant time and the relevant current can be different. C1 Grade index related to time
C1.1 When I=n-in
Specified error=grade index=5%(Example)
C1.2 When I=-\·I
Specified error=(grade index)·m=(5%), m(Example)C1. 3 When I=n\·I
Specified error=(grade index)·m=(5%)·m(Example)-multiples of basic current;
Where: n—
corresponds to the grade index multiple of n.
+5）m
+(%)-
（5%)m
（5%)·m
C2 Grade index related to current
Specified error is related to·I value. At t→, the specified error is grade index=25%(Example)——Corresponds to the temperature of · I.
Because:
The above formula can be written as:
GB/T14598.15—1998
B2 The manufacturer can publish the following thermal balance curve with the original load specific force as the parameter Load current before overload
Basic current
GB/T14598.15—1998
Appendix C
(Appendix of the standard)
Example of determining accuracy
The level index of the relevant time and the relevant current can be different. C1 Grade index related to time
C1.1 When I=n-in
Specified error=grade index=5%(Example)
C1.2 When I=-\·I
Specified error=(grade index)·m=(5%), m(Example)C1. 3 When I=n\·I
Specified error=(grade index)·m=(5%)·m(Example)-multiples of basic current;
Where: n—
corresponds to the grade index multiple of n.
+5）m
+(%)-
（5%)m
（5%)·m
C2 Grade index related to current
Specified error is related to·I value. At t→, the specified error is grade index=25%(Example)——Corresponds to the temperature of · I.
Because:
The above formula can be written as:
GB/T14598.15—1998
B2 The manufacturer can publish the following thermal balance curve with the original load specific force as the parameter Load current before overload
Basic current
GB/T14598.15—1998
Appendix C
(Appendix of the standard)
Example of determining accuracy
The level index of the relevant time and the relevant current can be different. C1 Grade index related to time
C1.1 When I=n-in
Specified error=grade index=5%(Example)
C1.2 When I=-\·I
Specified error=(grade index)·m=(5%), m(Example)C1. 3 When I=n\·I
Specified error=(grade index)·m=(5%)·m(Example)-multiples of basic current;
Where: n—
corresponds to the grade index multiple of n.
+5）m
+(%)-
（5%)m
（5%)·m
C2 Grade index related to current
Specified error is related to·I value. At t→, the specified error is grade index=25%(Example)
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