GB 311.1-2012Insulation co-ordination -- Part 1: Definitions, principles and rules (English PDF)

1.1 Scope

This section applies to the highest voltage device above 1kV three-phase AC power system used in the following power transmission indoors and outdoors equipment.

a) Transformer. power transformers, shunt reactors, current limiting reactors, Petersen coil and the electromagnetic voltage transformer, current transformer;

b) high-voltage electrical categories. circuit breaker, disconnecting switch, a load switch, earth switch, fuse, prefabricated substation, closed switch to Preparation, enclosed switchgear, a combination of electrical appliances;

c) power capacitors, the coupling capacitor (capacitor voltage transformer comprising a), shunt capacitor, AC filter capacitor;

d) high-voltage power cable;

e) post insulators, wall bushing and the like.

1.2 NA range

a) mounted on the insulation with severe contamination or harmful gases, vapors, chemical equipment in case of deposits;

b) Relative humidity is high and condensation prone indoor applications device.

3.1 Normal environmental conditions

Withstand voltage selected from Table 2 and Table 3 below normal environmental conditions.

a) ambient air temperature does not exceed 40 °C and measured to 24h average does not exceed 35 °C. Minimum ambient air temperature is divided into three Level. -10 °C, -25 °C and -40 deg.] C;

b) altitude does not exceed 1000m;

c) ambient air is not significantly dust, smoke, corrosive gases, vapors or salt contamination. Filthy grade level does not exceed C (See GB/T 26218.1);

d) condensation and deposition typically occurs. Consider the sediment appears to dew, condensation, fog, rain, snow or frost forms.

3.2 Standard reference atmospheric conditions

Standardized withstand voltage applicable to the standard reference atmospheric conditions.

a) Temperature. t0 = 20 °C;

b) Pressure. p0 = 101.3kPa (1013mbar);

c) Absolute humidity. h0 = 11g/m3.

3.3 Special environmental conditions

3.3.1 Test Voltage ambient air temperature is higher than 40 °C apparatus, the outer insulation in the dry state should take this nominal section Withstand voltage value is multiplied by the temperature correction factor KT.

KT = 1 0.0033T (-40) where.

T --- ambient air temperature, °C.

3.3.2 For altitudes above 1000m, 4000m, but the device does not exceed the dielectric strength of the insulation shall be outer altitude correction, the correction See Appendix B.

3.4 Grounding equipment for power system neutral point

The highest voltage 126kV active or non-effectively grounded system (direct) grounding system; maximum voltage of 126kV and above should have Effect (direct) grounding system.

Terms and definitions 4 the following terms and definitions apply to this document.

Insulation coordination After considering over-voltage protection measures adopted, the decision on the possible role of voltage equipment, and insulation and may affect the characteristics of the device according to Factors insulation properties, dielectric strength equipment to determine the reasonableness of the security operation and technical and economic aspects.

[Modification GB/T 2900.19-1994, definitions 3.23] Note. "dielectric strength" refers to a device rated insulation level or standard insulation level by 4.35 and 4.36, respectively defined.

External insulation Solid insulation exposed in the atmosphere in the air gap and the surface equipment, it is subjected to the applied voltage and by the external atmospheric conditions, and the other field, Effects such as contamination, humidity, and other pests.

[GB/T 2900.19-1994, definitions 3.24]

NOTE. insulating outer weather protective or may be a non-climate protection, are designed to run inside or outside the protective body.

Insulating internalinsulation Solid, liquid or gas unaffected by atmospheric conditions other external equipment insulation.

[GB/T 2900.19-1994, definitions 3.25] 4.4 Self-restoring insulation After disruptive discharges during the test, after a short time, it can be fully restored the insulating properties of the insulation.

[Modification GB/T 2900.19-1994, definitions 3.28] Note. These are generally insulated external insulation, but is not required.

Non-self-restoring insulation After disruptive discharges during the test, or not fully recover the loss of insulation properties of the insulation.

[GB/T 2900.19-1994, definitions 3.29]

NOTE. 4.4 and 4.5 is defined only by the action of the test applies the discharge voltage during the insulation test caused. However, discharge may be caused at runtime Since self-restoring insulation partial or complete loss of its original insulating properties.

Terminal insulating structure insulationconfigurationterminal Voltage may be applied to any of the terminals between any two terminals on the insulation. Terminals are.

a) phase terminal. the terminal is applied to neutral voltage of the system between its neutral point and the run-time;

b) neutral point terminal. equivalent to the system neutral point or neutral point terminal (neutral terminal of the transformer and the like);

c) ground terminal. In operation, the ground terminal is always fixed (the transformer housing, the base of the disconnector, the tower frame, ground Plate or the like).

Insulating structure insulationconfiguration Complete geometry and operation of all of the contacts by an insulator composed of insulating. It includes all of the elements (electrical insulating properties of the dielectric effect Edge member and the conductive member). Insulating structure is divided into the following categories.

4.7.1

Three-phase insulating structure three-phaseinsulationconfiguration Having three phase terminals, a neutral terminal structure and a ground terminal.

4.7.2

Relatively (PE) insulation phase-to-earth (pe) insulationconfiguration Excluding the two phase terminals of a three phase insulating structure, and except in special circumstances, neutral terminal is grounded.

4.7.3

Phase (pp) insulation phase-to-phase (pp) insulationconfiguration Excluding a three-phase insulating structure of a phase terminal. In special cases, neutral and ground terminals negligible.

4.7.4.

Longitudinal (TT) insulation longitudinal (tt) insulationconfiguration with two phase terminal and a ground terminal of the insulating structure. (Two) phase terminals belonging to the same phase of the three-phase system, which is temporarily Divided into two separate charging portion (e.g., opening the switch means). Belonging to the other two phases excluding the four terminals or ground. Special Case, that one of the two phase terminals is grounded.

The nominal system voltage nominalvoltageofasystem Un or represents a recognition system for a suitable voltage value is approximated.

[GB/T 2900.19-1994, defined 2.4] 4.9 Maximum system voltage highestvoltageofasystem Us Under normal operating conditions, the system at any point in any of the effective value of the maximum operating voltage of a timing phase occurring.

[Modification GB/T 2900.19-1994, defined 2.5] 4.10 Highest voltage for equipment Um the apparatus insulating properties as well as other related standards associated equipment designed highest voltage RMS phase. In normal Under operating conditions specified by the relevant Technical Committee, the voltage can be continuously applied to the device.

[Modification GB/T 2900.19-1994, defined 2.7] 4.11 Neutral insulation system isolatedneutralsystem in addition to protected, high-impedance ground measurement, the ungrounded system.

[GB/T 2900.19-1994, definitions 3.13] 4.12 Fixed neutral grounding system solidlyearthedneutralsystem Directly grounded neutral system.

[Modification GB/T 2900.19-1994, definitions 3.14] 4.13 (Neutral) impedance grounding system impedanceearthed (neutral) system to limit the ground fault current, the impedance grounded neutral system.

[Modification GB/T 2900.19-1994, definitions 3.16] 4.14 (Neutral) resonant grounding system resonantearthed (neutral) system One or more neutral grounding through the reactor system, the reactor is approximately single-phase ground fault current compensating capacitive component. neutral Compensation point can be approximated by single-phase ground fault current component of the capacitive reactance of the grounding system.

[Modification GB/T 2900.19-1994, definitions 3.15] Note. the resonance grounding system flowing through the fault point current is limited to the extent that residual air can be generally self-extinguishing arc of a ground fault.

4.15

Ground fault factor earthfaultfactor in a given system configuration of a three-phase system given point, during any failure of the system has little influence one or more phases, Jian when all phases working relatively highest frequency voltage effective value of the point is relatively fault-free RMS voltage frequency ratio.

[GB/T 2900.19-1994, definitions 3.17] 4.16 Overvoltage in a three-phase system voltage Us is the highest, the peak value exceeds the maximum system voltage peak opposite (Us × 2/3) or maximum interphase or any relative phase to phase voltage waveforms of the peak pressure (2uS) respectively opposite phase or overvoltage.

When the overvoltage value expressed in unit value, contrast, and white over the reference value of the voltage Us × 2/3, respectively and 2uS (in pu Representation).

[Modification GB/T 2900.19-1994, Definitions 3.1]

NOTE. Unless expressly stated otherwise, for example, surge arresters usually PU overvoltage value (equal Us × 2/3). FIG.

4.17

Voltage and over-voltage classification classificationofvoltageandovervoltage Waveform and its duration, and overvoltage can be divided into the following.

Note. in Table 1 given below about 6 and overvoltage conditions more detail.

4.17.1

Length (frequency) voltage continuous (powerfrequency) voltage Rms has a stable, sustained action working on either one of the pair of terminal insulation frequency voltage.

4.17.2

Temporary overvoltage; TOV Longer duration power frequency overvoltage.

[Modification GB/T 2900.19-1994, defined 3.6]

NOTE. overvoltage may be undamped or weakly damped. In some cases, the frequency may be several times lower than the frequency or several times.

4.17.3

Transient overvoltage A few milliseconds or less in duration over-voltage, typically high damping oscillation or oscillations.

[GB/T 2900.19-1994, defined 3.7] Note. The temporary overvoltage transient overvoltage appears likely to follow, in this case, consider these two overvoltage are two separate processes.

Transient over-voltage is divided into the following categories.

4.17.3.1

Overvoltage slow wavefront (operation) slow-frontovervoltage; SFO One kind of transient overvoltage, typically unidirectional, time to peak is 20µs \u003cTp<=5000µs,而波尾持续时间T2<= 20ms.

4.17.3.2

Fast wave front overvoltage (lightning) fast-frontovervoltage; FFO One kind of transient overvoltage, typically unidirectional, reaches a peak time of 0.1µs \u003cT1<=20µs,波尾持续时间T2\u003c300µs。 4.17.3.3 Express wavefront overvoltage very-fast-frontovervoltage; VFFO One kind of transient overvoltage, typically unidirectional, time to peak Tf<=0.1µs, with or without superimposed oscillation, the oscillation frequency 30kHz \u003cf\u003c100MHz之间。

NOTE. Express wavefront also known overvoltage VFFO Laid fast transient overvoltages VFTO (very-fast-transientovervoltage).

4.17.4

United overvoltage combinedovervoltage in the simultaneous action of phase (or longitudinal) between the two voltages to each terminal and the insulated phase terminals of the two component composition. It was attributed to Component having a higher peak (temporarily, before the slow waves, and the fast wave front before the wave express) a class.

4.18

Standard test voltage waveform standardvoltageshapesfortest 4.18.1 ~ 4.18.5 voltage waveform has been normalized.

Note. For the following three standard voltage 4.18.1 ~ 4.18.3 More detailed information is given in the GB/T 16927.1 and in Table 1.

4.18.1

Standard short-frequency voltage standardshort-durationpower-frequencyvoltage it has a frequency between 45Hz ~ 55Hz, duration of the sinusoidal voltage 60s.

NOTE. IEC 60071-1 frequency range of 48Hz ~ 62Hz, 60Hz consideration of the NA of the grid, it will be set to the frequency range 45Hz ~ 55Hz, to conform to GB/T 16927.1.

4.18.2

Standard operating impulse voltage standardswitchingimpulsevoltage Having a peak time is 250µs and the half value of the surge voltage 2500µs.

4.18.3

Standard lightning impulse voltage Having a wave front time of 1.2µs and a half value of the surge voltage 50µs.

4.18.4

Standard joint operating impulse voltage standardcombinedswitchingimpulsevoltage for phase insulation, combined with the opposite polarity switching impulse voltage of the two components.

Positive polarity switching impulse voltage is a standard component and the negative component of the peak and half-value time is not less than the positive polarity electric shock Voltage value corresponding to the operation of the surge voltage. Two impact should reach a peak at the same instant. Thus the peak voltage of these components combined peak Sum.

4.18.5

Joint standard voltage standardcombinedvoltage of vertical insulation, the surge voltage is a combined voltage as a standard terminal, the voltage of the other terminal of the power frequency. Anti-shock is applied to the component Peak frequency voltage polarity.

4.19

Representative overvoltage Urp Suppose on the insulation and by generating a runtime due to various reasons given the same kind of over-voltage insulating effect of Voltage.

They consist of a voltage waveform corresponding category criteria and can represent a value or set of values, or some characteristic of the operating conditions Values to define the frequency distribution.

Note. This definition also applies to the continuing work indicates the operating voltage frequency voltage insulation effect.

4.20

Overvoltage limiting device it means the peak voltage or duration or both limits are used to limit too. They can be divided into prevention guard device (e.g., pre-accessible electrical Resistor) or the protector (arrester).

4.21

Lightning (or operations) impact protection level lightning (orswitching) impulseprotectivelevel; LIPL or SIPL Upl (or Ups) Under a predetermined condition, the receiving terminal lightning protection device (or operations) the maximum allowable voltage peak impact.

4.22

Performance indicators performancecriterion Selecting a reference insulated, so that the probability that the insulating effect of injury or equipment in various types of continuous operation of the device that causes the voltage Reduced to an acceptable level the economic and run. Typically, the term pharmaceutically insulation failure rate number (fault year, twice a Symptom Between the years, the risk of failure, etc.) to represent the indices.

4.23

Withstand voltage when the test voltage is applied to pressure test under specified conditions. During the pressure test allowed the predetermined disruptive discharge frequency. Withstand voltage.

a) conventional withstand voltage setting. At this time, the number of discharges allows a disruptive zero, i.e. tolerability probability Pw = 100%.

b) statistical withstand voltage. Almost tolerance permitted tolerance disruptive discharge probability with a predetermined number of times related to this predetermined section Ratio Pw = 90%.

Note. In this section, a non-self-restoring insulation by setting a predetermined withstand voltage customary; while a predetermined statistical self-restor...