CN111224385B

CN111224385B - Disconnection protection method for comparing voltage amplitude difference of two side wires of line and matching of spare power automatic switching

Info

Publication number: CN111224385B
Application number: CN201911247207.8A
Authority: CN
Inventors: 刘昶; 胡浩; 马骏毅; 孙东杰; 朱燕妮; 杨静; 汤勋; 赵伟; 朱文韬
Original assignee: State Grid Jiangsu Electric Power Co ltd Zhenjiang Power Supply Branch
Current assignee: State Grid Jiangsu Electric Power Co ltd Zhenjiang Power Supply Branch
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2021-03-02
Anticipated expiration: 2039-12-09
Also published as: CN111224385A

Abstract

The invention discloses a disconnection protection method for comparing voltage amplitude difference of two side lines of a line with matching of spare power automatic switching. The invention adopts a relay protection scheme that the voltage information at two sides of the line is transmitted through the optical fiber channel of the line, the line voltage amplitude difference at two sides of the line is compared to identify the line break, the circuit breaker at the power supply side of the line is tripped or the circuit breaker at the load side is tripped, then the substation spare power automatic switching action at the load side is used for starting the circuit breaker at the trip incoming line and closing the circuit breaker at the spare power supply, so that the transformer losing the power supply is recovered to the power supply on the spare power supply, thereby effectively preventing the influence of the phase-lacking power supply of the transformer on the power grid and.

Description

Disconnection protection method for comparing voltage amplitude difference of two side wires of line and matching of spare power automatic switching

Technical Field

The invention relates to a disconnection protection method for comparing voltage amplitude difference of two side lines of a line and matching with a spare power automatic switching device, and belongs to the technical field of protection and control of an electric power transmission and distribution network.

Background

At present, the line disconnection phenomenon of 3-66 kV (including 3, 6, 10, 20, 35 and 66kV) lines occurs in power grids in various places, and the line disconnection causes the phase-loss operation of a transformer supplied by the lines, so that the three-phase voltage of the transformer is asymmetric, the influence is generated on load power supply, electrical equipment can be damaged, for example, a motor is damaged due to the phase-loss operation. In the prior art, no relay protection device and method specially aiming at the disconnection of a 3-66 kV line exist. The invention provides a single-phase disconnection relay protection method which is used for transmitting voltage information of two sides of a line through a line optical fiber channel at a load end transformer substation, comparing line voltage amplitude differences of the two sides of the line, identifying 3-66 kV line disconnection, tripping a circuit breaker on a power supply side or a load side of the line, and recovering power supply through a backup automatic switch of the load end 3-66 kV transformer substation. .

Disclosure of Invention

The invention aims to provide a disconnection protection method for comparing the voltage amplitude difference of two side lines of a line with the matching of a spare power automatic switching device, which is used for a load end 3-66 kV transformer substation, transmits voltage information of the two sides of the line through a line optical fiber channel, compares the voltage amplitude difference of the two sides of the line to identify the disconnection of the line, a circuit breaker at a power supply side of a trip circuit or a circuit breaker at a load side, and recovers power supply by the spare power automatic switching device of the load end 3-66 kV transformer substation.

The purpose of the invention is realized by the following technical scheme:

a disconnection protection method for comparing the voltage amplitude difference of two side wires of a line with the matching of spare power automatic switching comprises the following steps:

judging the conditions of starting a circuit breaker at a line-jumping power supply side or a circuit breaker at a load side by line disconnection and recovering power supply by a backup power automatic switch:

1.1 judging No. 1 line disconnection jumping No. 1 line disconnection line power supply side circuit breaker 4DL or load side circuit breaker 1DL and starting standby power supply circuit breaker 2DL or 3DL switching-on by load side standby power automatic switching, and starting No. 1 line disconnection alarm condition

Collecting power supply side bus PT secondary AB line voltage value U_A1B1BC line voltage value U_B1C1CA line voltage value U_C1A1And the voltage value U of the secondary AB line of the I-section bus PT of the load end 3 transformer substation_A2B2BC line voltage value U_B2C2CA line voltage value U_C2A2；

Conditions are as follows: (1) in No. 1 line, the voltage value U of the secondary AB line of the I section bus PT on the power supply side_A1B1Absolute value and load end transformer substation I section bus PT secondary AB line voltage value U_A2B2Difference of absolute value, power source side I section bus PT secondary BC line voltage value U_B1C1Absolute value and load end transformer substation I section bus PT secondary BC line voltage value U_B2C2Difference of absolute value, power source side I section bus PT secondary CA line voltage value U_C1A1Absolute value and load end transformer substation I section bus PT secondary CA line voltage value U_C2A2Of the three differences, two differences being 0.38E_abTo 0.55E_abA difference of 0.1E or less_ab；E_abThe rated line voltage value of the power supply;

(2) power supply end corresponding bus PT secondary AB line voltage value U_A1B1Greater than or equal to 0.9E_ab1.1E or less_ab；

(3) Power supply end corresponding bus PT secondary BC line voltage value U_B1C1Greater than or equal to 0.9E_ab1.1E or less_ab；

(4) Power supply end corresponding bus PT secondary CA line voltage value U_C1A1Greater than or equal to 0.9E_ab1.1E or less_ab；

(5) The power supply end line breaker 4DL of the line 1 is at the switching-on position;

(6) the load side line breaker 1DL of line No. 1 is in the on position;

if all the conditions are met, identifying and judging that the No. 1 power line is broken, carrying out broken line protection in the line protection of the superior power side transformer substation, and tripping a No. 1 power line power side circuit breaker 4 DL; as the No. 1 power supply circuit loses power supply, the load end transformer substation is in standby automatic switching action, the No. 1 power supply incoming line breaker 1DL is started to be opened, and the standby power supply breaker 2DL or 3DL is closed; or tripping a No. 1 power line load side circuit breaker 1DL for line break protection in No. 1 line protection of a load side transformer substation; as the No. 1 power supply circuit loses power supply, the load end transformer substation is in standby automatic switching action, and the standby power supply breaker 2DL or 3DL is started to be closed; the transformer without power supply is recovered to the standby power line for power supply, and the No. 1 line is started to be off for alarming;

1.2 conditions for judging 5DL of No. 2 line disconnection tripping No. 2 disconnection line power supply side circuit breaker or 2DL of load side circuit breaker and starting 1DL or 3DL of standby power supply circuit breaker by load side backup automatic switch and starting No. 2 line disconnection alarm

Collecting power supply side bus PT secondary AB line voltage value U_A1B1BC line voltage value U_B1C1CA line voltage value U_C1A1Second-stage bus PT secondary AB line voltage value U of load-end transformer substation_A2B2BC line voltage value U_B2C2CA line voltage value U_C2A2；

Conditions are as follows: (1) in No. 2 line, the voltage value U of secondary AB line of II section buses PT on power supply side_A1B1Absolute value and load end II section bus PT secondary AB line voltage value U_A2B2Difference of absolute value, secondary BC line voltage value U of II section bus PT of power supply side_B1C1Absolute value and load end II section bus PT secondary BC line voltage value U_B2C2The difference of absolute values, the voltage value U of the secondary CA line of the PT bus line of the II section of the power supply side_C1A1Absolute value and load end II section bus PT secondary CA line voltage value U_C2A2Of the three differences, two differences being 0.38E_abTo 0.55E_abA difference of 0.1E or less_ab；E_abThe rated line voltage value of the power supply;

(5) The power supply end circuit breaker 5DL of the No. 2 circuit is at the switching-on position;

(6) the load side line breaker 2DL of line No. 2 is in the on position;

if the conditions are all met, identifying and judging that the No. 2 power line is broken, carrying out broken line protection in the line protection of the superior power side substation, and tripping a No. 2 power line power side breaker 5 DL; as the No. 2 power supply line loses power supply, the load end substation is in standby automatic switching action, the No. 2 power supply incoming line breaker 2DL is started to be tripped, the standby power supply breaker 1DL or 3DL is closed, or the line break protection in the No. 2 line protection of the load end substation is used for tripping the No. 2 power supply line load side breaker 2 DL; as the No. 2 power supply circuit loses power supply, the load end transformer substation is in standby automatic switching action, and the standby power supply circuit breaker 1DL or 3DL is started to be closed; the transformer without power supply is recovered to the standby power line for power supply, and the No. 2 line is started to be disconnected for alarm.

The object of the invention can be further achieved by the following technical measures:

the disconnection protection method for comparing the voltage amplitude difference of the two side wires of the circuit and matching with the spare power automatic switching is applied to a mode that a neutral point of a transformer is not grounded or is grounded through an arc suppression coil and a low-resistance grounding system.

The disconnection protection method for comparing the voltage amplitude difference between two side wires of the line and matching with the spare power automatic switching device is characterized in that the PT secondary side rated line voltage value E_abIs 100V.

According to the wire breakage protection method for comparing the voltage amplitude difference of the two lateral wires of the circuit with the matching of the spare power automatic switching, t1 is 0.1-0.2 second when the three phases are not in phase when the breaker is closed.

Compared with the prior art, the invention has the beneficial effects that:

1. the method fully utilizes the fault characteristics of the secondary voltage of the power supply end and the load end substation bus PT during the single-phase line break of the line, compares the voltage amplitude difference of the buses at the two ends of the line, and identifies the circuit breaker at the power supply side or the load side of the single-phase line break line jump of the line, thereby being simple and easy.

2. The invention adopts a relay protection scheme that the voltage information at two sides of the line is transmitted through the optical fiber channel of the line, the line voltage amplitude difference at two sides of the line is compared to identify the line break, the circuit breaker at the power supply side of the line is tripped or the circuit breaker at the load side is tripped, then the substation spare power automatic switching action at the load side is used for starting the circuit breaker at the trip incoming line and closing the circuit breaker at the spare power supply, so that the transformer losing the power supply is recovered to the power supply on the spare power supply, thereby effectively preventing the influence of the phase-lacking power supply of the transformer on the power grid and.

3. The method of the invention is implemented by adopting the line protection devices at two sides of the line, and does not need to increase hardware equipment.

Drawings

FIG. 1 is a schematic diagram of a primary system of a superior substation with 35kV side not grounded or grounded through an arc suppression coil;

FIG. 2 is a vector diagram of the voltage of a 35kV bus on the power supply side without grounding or through arc suppression coils;

FIG. 3 is a vector diagram of the voltage of a 35kV bus on the load side without grounding or through an arc suppression coil;

FIG. 4 is a schematic diagram of a primary system with a 35kV line break and a load side line break grounded;

FIG. 5 is a vector diagram of the voltage of a 35kV bus on the load side at a load side disconnection point;

FIG. 6 is a schematic diagram of a primary system with a 35kV line broken and a power supply side grounded;

FIG. 7 is a vector diagram of the voltage of a 35kV bus at the ground power supply side at a power supply side disconnection;

FIG. 8 is a vector diagram of the voltage of a 35kV bus at the grounded load side at the power supply side disconnection;

fig. 9 is a schematic diagram of a primary system of a superior substation with 35kV side grounded through a resistor;

FIG. 10 is a vector diagram of 35kV bus voltage at the 35kV side of the upper-level substation via the resistance grounding power supply side;

fig. 11 is a voltage vector diagram of a 35kV bus at a 35kV side of an upper-level substation through a resistance grounding load side;

FIG. 12 is a schematic diagram of a primary system with a 35kV line break and a load side line break grounded;

FIG. 13 is a vector diagram of the voltage of a 35kV bus at the load side which is grounded at a load side disconnection;

FIG. 14 is a schematic diagram of a 35kV primary system with a power supply side disconnected and a ground connection;

FIG. 15 is a schematic diagram of the disconnection protection of the present invention;

FIG. 16 is a primary main wiring diagram of a single bus segment of a 35kV substation;

FIG. 17 is a primary main wiring diagram of an inner bridge of a 35kV substation;

FIG. 18 is a primary main wiring diagram of an enlarged inner bridge of a 35kV substation;

fig. 19 is a primary main connection of a 35kV line transformer set of a 35kV substation.

Detailed Description

The invention is further described with reference to the following figures and specific examples.

Firstly, analyzing fault characteristics by taking 35kV line breakage as an example:

1.1 ungrounded or arc-suppression coil grounding system

1.1.135 kV line broken wire

Fig. 1 is a schematic diagram of a 35kV primary disconnection system, taking an a-phase stub as an example. The 35kV side of the upper-level transformer substation is not grounded or is grounded through an arc suppression coil, and the 35kV neutral point of the 35kV transformer substation on the load side is not grounded. The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NIf alpha is broken for the 35kV neutral point voltage of the transformer of the power side transformer substation, the capacitance to ground of the bus side of the transformer substation from the broken line to the upper level is alpha C, and the capacitance to ground of the 35kV bus of the transformer substation from the broken line to the load side is (1-alpha) C.

1. Power supply side bus voltage analysis

Analyzing to obtain the voltage of a bus at the 35kV side of the upper-level transformer substation as follows:

(1) in the formula (I), the compound is shown in the specification,

the voltage of a power side 35kV bus A1B1 line, the voltage of a B1C1 line and the voltage of a C1A1 line are respectively. ,

the voltage of the 35kV side power line of the upper-level transformer substation is equal. The vector diagram of the voltage of the 35kV bus on the power supply side is shown in fig. 2, and as can be seen from fig. 2, when the phase A of the 35kV line is disconnected, the voltage of the three-phase line of the 35kV bus of the upper-level substation is unchanged and keeps symmetry. In the figure, alpha varies between 0 and 1, and 0 point is 0 in FIG. 2_α＝0To 0_α＝1When α is 1, point 0 is 0_α＝1At the point, when α is 0, 0 is 0_α＝0(the same applies below).

2. Load side bus voltage analysis

The 35kV load side bus voltage is analyzed as follows:

(2) in the formula (I), the compound is shown in the specification,

the line voltage of the load side 35kV bus A2B2, the line voltage of B2C2 and the line voltage of C2A2 are shown in a vector diagram of the load side 35kV bus in figure 3.

As can be seen from FIG. 3, when the 35kV line is disconnected, the load side

Is composed of

And

in the opposite direction and of magnitude

1.1.235 kV line disconnection and load side disconnection grounding

Fig. 4 is a schematic diagram of a 35kV line break and load side line break grounding primary system, taking an a-phase stub as an example. The 35kV side of the upper-level transformer substation is not grounded, and the 35kV neutral point of the 35kV transformer substation on the load side is not grounded. The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NThe voltage of a 35kV neutral point of a transformer substation on a power supply side is alpha C on the bus side of a transformer substation from a broken line to a superior substation, and the capacitance of the 35kV bus of the transformer substation from the broken line to a load side is (1-alpha) C.

1. Power supply side bus voltage analysis

The analysis was as in 1.1.1.

2. Load side bus voltage analysis

The 35kV load side bus voltage is analyzed as follows:

the vector diagram of the 35kV bus voltage on the load side is shown in figure 5.

As can be seen from FIG. 5, when the 35kV line is broken and the load side broken line is grounded,

is equal to

Along with the difference of the distance of the broken line close to the power supply side bus, alpha varies between 0 and 1, and simultaneously

In that

To a change of 0, point 0 being as in FIG. 5 0_α＝0To 0_α＝1The number of the intermediate change is changed,

is as large as

Change to E_BWhile varying between

Size of (2)

Change to E_CAnd (4) change.

1.1.335 kV line disconnection and power supply side disconnection point grounding

Fig. 6 is a schematic diagram of a primary system with a 35kV line broken and a power supply side grounded, taking an a-phase short line as an example. The 35kV side of the upper-level transformer substation is not grounded, and the 35kV neutral point of the 35kV transformer substation on the load side is not grounded. The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NThe voltage of a 35kV neutral point of a transformer substation on a power supply side is alpha C on the bus side of a transformer substation from a broken line to a superior substation, and the capacitance of the 35kV bus of the transformer substation from the broken line to a load side is (1-alpha) C.

1. Power supply side bus voltage analysis

Analyzing the voltage of a bus at the 35kV side of the upper-level transformer substation:

the vector diagram of the 35kV bus voltage at the power supply side is shown in figure 7.

As can be seen from fig. 7, when the 35kV line is disconnected and the power supply side is grounded, the three line voltages are constant and symmetrical.

2. Load side bus voltage analysis

The 35kV load side bus voltage is analyzed as follows:

the vector diagram of the 35kV bus voltage on the load side is shown in figure 8.

When the 35kV line is broken, the load side

Is composed of

And

in the opposite direction and of magnitude

1.2 grounding System via a resistor

1.2.135 kV line broken wire

Fig. 9 is a schematic diagram of a 35kV primary disconnection system, taking an a-phase stub as an example. The 35KV power supply system of the 35kV side transformer substation of the upper-level transformer substation is grounded through a resistor (R is generally 10, 20 and 100 omega). The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NIf alpha is broken for the 35kV neutral point voltage of the transformer of the power side transformer substation, the capacitance to ground of the bus side of the transformer substation from the broken line to the upper level is alpha C, and the capacitance to ground of the 35kV bus of the transformer substation from the broken line to the load side is (1-alpha) C.

1. Power supply side bus voltage analysis

(6) in the formula (I), the compound is shown in the specification,

the voltage of a power side 35kV bus A1B1 line, the voltage of a B1C1 line and the voltage of a C1A1 line are respectively. The vector diagram of the 35kV bus voltage on the power supply side is shown in FIG. 10.

As can be seen from fig. 10, when a phase a of the 35kV line is disconnected, the voltages of the three-phase lines of the 35kV bus of the upper-level substation are unchanged and are kept symmetrical. With the distance of the broken line close to the power supply side bus bar different, the 0 point is 0 in FIG. 10_α＝0To 0_α＝1When α is 1, point 0 is 0_α＝1At the point, when α is 0, 0 is 0_α＝0(same below) with U_NAt about ω CE_AThe variation from R to 0 (the cable line capacitance C is generally less than or equal to 0.55 mu F, and the overhead line is even smaller, so U_NIs a very small value, and is 0.55 mu F, U according to the grounding resistance of 20 omega, C_NIs 3.45^-3E_AAnd so can be ignored).

2. Load side bus voltage analysis

The 35kV load side bus voltage is analyzed as follows:

(7) in the formula (I), the compound is shown in the specification,

the line voltage of the load side 35kV bus A2B2, the line voltage of B2C2 and the line voltage of C2A2 are shown in a vector diagram of the load side 35kV bus in the figure 11.

As can be seen from FIG. 11, when the 35kV line is disconnected, the load side

Is composed of

And

in the opposite direction and of magnitude

1.2.235 kV line disconnection and load side disconnection grounding

Fig. 12 is a schematic diagram of a 35kV line break and load side line break grounding primary system, taking an a-phase stub as an example. The 35KV power supply system of the 35kV side transformer substation of the upper-level transformer substation is grounded through a resistor. The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NThe voltage of a 35kV neutral point of a transformer substation on a power supply side is alpha C on the bus side of a transformer substation from a broken line to a superior substation, and the capacitance of the 35kV bus of the transformer substation from the broken line to a load side is (1-alpha) C.

1. Power supply side bus voltage analysis

The analysis was as in 1.2.1.

2. Load side bus voltage analysis

The 35kV load side bus voltage is analyzed as follows:

the vector diagram of the 35kV bus voltage on the load side is shown in FIG. 13.

As can be seen from FIG. 13, when the 35kV line is disconnected and the load side disconnection is grounded, U is turned off_B2C2Is equal to E_BCAnd the distance is different along with the distance of the broken line close to the power supply side bus. Due to U_NCan be ignored, so U_A2B2、U_C2A2Is about equal to E_BAnd E_C。

1.2.335 kV line disconnection and power supply side disconnection point grounding

Fig. 14 is a schematic diagram of a primary system with a 35kV line broken and a power supply side grounded, taking an a-phase short line as an example. The 35KV power supply system of the 35kV side transformer substation of the upper-level transformer substation is grounded through a resistor. The power supply potentials at 35kV sides of the upper-level transformer substation are respectively set as E_A、E_B、E_C，U_NThe voltage of a 35kV neutral point of a transformer substation on a power supply side is alpha C on the bus side of a transformer substation from a broken line to a superior substation, and the capacitance of the 35kV bus of the transformer substation from the broken line to a load side is (1-alpha) C.

When the line is broken and the system side is grounded, the fault is a single-phase grounding short circuit fault, so that the zero sequence current protection action of the system transformer substation line trips, and reclosure cannot be coincided.

Analyzing the line breaking fault characteristics of the 3-66 kV line:

for three conditions of ungrounded, arc suppression coil grounded and resistance grounded systems, 35kV line breakage and load side line breakage grounded, 35kV line breakage and power supply side line breakage grounded, the power supply side line voltage is constant and symmetrical (for the resistance grounded systems, when the line breakage and system side grounded, single-phase grounding short circuit fault occurs, the zero-sequence current protection of the line trips actions).

Due to the grounding condition of the broken line of the 35kV line and the broken line of the power supply side, U_NCan be ignored, therefore, forThe two conditions of 35kV line breakage, 35kV line breakage and grounding at the power supply side broken line position, namely the load side bus line voltage and the load side

Is equal to

And

in the opposite direction and of magnitude

For the case that the 35kV line is broken and the load side is grounded,

is equal to

Alpha varies between 0 and 1 according to the distance between the broken line and the bus on the power supply side,

is as large as

Change to E_BWhile varying between

Is as large as

Change to E_CAnd (4) change.

In summary, when three conditions of 35kV line disconnection, 35kV line disconnection and grounding at the load side disconnection point, 35kV line disconnection and grounding at the power side disconnection point occur, the line voltage amplitude difference at the two sides of the line satisfies:

similarly, when a 3-66 kV line is broken, the bus line voltages on two sides of the line have the same fault characteristics.

The technical scheme of the method of the invention is as follows:

the transmission and distribution network applied by the method is 35kV single-bus subsection primary main connection (including 35kV single-bus primary main connection), 35kV inner bridging connection (shown in figure 17), 35kV expansion inner bridging connection (shown in figure 18) and 35kV line transformation group primary main connection (shown in figure 19) of a 35kV substation. Taking a 35kV substation as an example of a primary main connection of a 35kV single-bus subsection, other primary main connection protection methods are similar (in which fig. 19 is matched with a medium-voltage or low-voltage spare power automatic switch to recover power supply). The 35kV single-bus subsection primary main wiring general structure of the 35kV substation is as follows: the No. 1 power supply incoming line branch equipment and the No. 2 power supply incoming line branch equipment are respectively connected with a 35kV I section bus and a 35kV II section bus; a segmented circuit breaker 3DL is arranged between the 35kV first-segment bus and the second-segment bus, and the segmented circuit breaker 3DL is connected with a segmented current transformer CT in series; the circuit breaker 1DL is arranged at the interval of the No. 1 power supply inlet branch circuit, the circuit breaker 2DL is arranged at the interval of the No. 2 power supply inlet branch circuit, and the No. 1 power supply inlet branch circuit and the No. 2 power supply inlet branch circuit are respectively connected with a current transformer CT1 and a current transformer CT2 in series; in addition, the 35kV I section bus is also connected with a No. 1 transformer branch and a 35kV voltage transformer PT 1; the 35kV II section bus is also connected with a No. 2 transformer branch and a 35kV voltage transformer PT 2. There is circuit breaker 4DL No. 1 power inlet wire circuit power supply side, and there is circuit breaker 5DL No. 2 power inlet wire circuit power supply side. No. 1 power supply inlet wire power end 35kV generating line connects 35kV PT3, and No. 2 power supply inlet wire power end 35kV generating line connects 35kV PT 4. The 35kV line is provided with an optical fiber channel and line optical fiber differential protection.

Aiming at the 35kV single-bus subsection primary main connection, a scheme that voltage information on two sides of a line is transmitted through a 35kV line optical fiber channel is implemented in an upper-stage transformer station, line voltage amplitude difference on two sides of the line is compared to identify the line breakage of the 35kV line, a breaker on the power supply side or a breaker on the load side of the 35kV broken line is tripped, and power supply is recovered through a spare power automatic switch of a 35kV transformer substation on the load side is adopted, so that the field operation requirement is met.

As shown in fig. 15, the disconnection protection method for comparing the voltage amplitude difference between the two sides of the line and the spare power automatic switching device of the present invention includes:

judging the conditions of 35kV line power supply side circuit breaker or load side circuit breaker tripping in 35kV line disconnection starting and 35kV spare power automatic switching power supply recovery

1.1 judging the 4DL of the 1 # 35kV line disconnection tripping 1 # 35kV line disconnection line power supply side circuit breaker or the 1DL of the load side circuit breaker and the 2DL or 3DL of the load side 35kV backup power supply circuit breaker started by the load side 35kV backup power automatic switch, and starting the 1 # 35kV line disconnection alarm condition

Acquiring voltage value U of secondary AB line of 35kV bus PT on power side_A1B1BC line voltage value U_B1C1CA line voltage value U_C1A1And the voltage value U of the secondary AB line of the I-section bus PT of the 35kV transformer substation at the load end_A2B2BC line voltage value U_B2C2CA line voltage value U_C2A2。

(1) Dividing the PT secondary line voltage values of 35kV power side and I section buses of a load end of a No. 1 35kV line into three groups according to AB line voltage, BC line voltage and CA line voltage, and respectively satisfying that two difference values in the difference values of the absolute value of the line voltage of the power side and the absolute value of the line voltage of the load end are more than or equal to 0.38E_abAnd 0.55E or less_abA difference of 0.1E or less_ab。

(2) Power end corresponds 35kV generating line PT secondary AB line voltage value U_A1B1Greater than or equal to 0.9E_ab1.1E or less_ab；

(3) Power end corresponds 35kV generating line PT secondary BC line voltage value U_B1C1Greater than or equal to 0.9E_ab1.1E or less_ab；

(4) Power end corresponds 35kV generating line PT secondary CA line voltage value U_C1A1Greater than or equal to 0.9E_ab1.1E or less_ab；

(5) The power supply end 35kV line breaker 4DL of the No. 1 35kV line is at the on position.

(6) The load side 35kV line breaker 1DL of No. 1 35kV line is in the on position.

And if the conditions are all met, identifying and judging that the No. 1 35kV power line is broken, carrying out 35kV broken line protection in the 35kV line protection of the upper-level power supply side transformer substation, and tripping the No. 1 35kV power supply line power supply side circuit breaker 4 DL. Because the No. 1 35kV power line loses power, the load end 35kV transformer substation 35kV spare power automatic switching action starts to trip off the No. 1 35kV power incoming line circuit breaker 1DL, closes the spare power circuit breaker 2DL or 3DL (or 35kV disconnection protection in the load end 35kV transformer substation No. 1 kV circuit protection, the trip No. 1 No. 35kV power line load side circuit breaker 1 DL. starts to close the spare power circuit breaker 2DL or 3DL due to the fact that the No. 1 35kV power line loses power, and the load end 35kV transformer substation 35kV spare power automatic switching action restores the transformer losing power to the spare power line for power supply. And simultaneously, starting No. 1 35kV line disconnection alarm.

1.2 judging the condition of switching on 5DL of 2 # 35kV line breaking tripping 2 # 35kV line breaking line power supply side circuit breaker or 2DL of load side circuit breaker and 1DL or 3DL of backup power supply circuit breaker started by load end 35kV backup automatic switch, and starting 2 # 35kV line breaking alarm

Acquiring voltage value U of secondary AB line of 35kV bus PT on power side_A1B1BC line voltage value U_B1C1CA line voltage value U_C1A1Second-stage bus PT secondary AB line voltage value U of 35kV transformer substation at load end_A2B2BC line voltage value U_B2C2CA line voltage value U_C2A2。

(1) Dividing the PT secondary line voltage values of II sections of buses at the 35kV power side and the load end of a No. 2 35kV line into three groups according to AB line voltage, BC line voltage and CA line voltage, and respectively satisfying the difference between the absolute value of the line voltage at the power side and the absolute value of the line voltage at the load end, wherein the two values are more than or equal to 0.38E_abAnd 0.55E or less_abOne is less than or equal to 0.1E_ab。

(5) And a power supply end 35kV line breaker 5DL of the No. 2 35kV line is at the switching-on position.

(6) The load side 35kV line breaker 2DL of 35kV line No. 2 is in the on position.

And if the conditions are all met, identifying and judging that the No. 2 35kV power line is broken, carrying out 35kV broken line protection in the 35kV line protection of the upper-level power supply side transformer substation, and tripping a No. 2 35kV power supply line power supply side circuit breaker 5 DL. Because the 35kV power line 2 loses power, the 35kV substation 35kV spare power automatic switching action at the load end starts to trip off the 35kV power incoming line circuit breaker 2DL at the number 2, and closes the spare power circuit breaker 1DL or 3DL (or the 35kV disconnection protection in the protection of the 35kV line at the load end 35kV substation 2, the circuit breaker 2 DL. at the load side of the 35kV power line 2 is started to close the spare power circuit breaker 1DL or 3DL because the 35kV power line 2 loses power, so that the transformer losing power is restored to the spare power line for power supply. And simultaneously, starting No. 2 35kV line disconnection alarm.

1.3 in 1.1 and 1.2 above:

(1) the method can be applied to a transformer neutral point ungrounded mode or arc suppression coil grounded mode and a low-resistance grounded system.

(2) The reason that the circuit breakers 1DL or 2DL and 4DL or 5DL on the two sides of the 35kV power inlet wire are arranged at the switching-on position is as follows: when a 35kV substation with a load end is arranged on a power supply incoming line, the bus voltage far away from the power supply incoming line can also sense the line disconnection information, and the standby power supply circuit breaker for closing of the standby automatic switching can be interfered; in addition, when a line PT is adopted, the power supply incoming line may have other load end 35kV substations, and if the power supply incoming line breaker of the load end 35kV substation trips slowly or refuses tripping, the power supply incoming line breaker of the backup automatic switching device may be interfered, and the backup automatic switching device may not act. The logic can be further optimized by adopting the condition of the 35kV power incoming line breaker at the switching-on position.

(3)E_abIs electricityThe source rated line voltage value is considered according to the power grid voltage fluctuation and is considered as +/-10% of the actual power grid rated voltage value, wherein: when the voltage value is larger than or equal to the rated line voltage value, the rated line voltage value of the power grid is considered to be 0.9 times; the rated line voltage value is less than or equal to 1.1 times of the rated voltage value of the power grid.

1.4 after the 35kV line is identified to be broken, the tripping scheme is as follows: (1) tripping off a breaker at the power supply side of the broken line; (2) tripping off a circuit breaker on the load side of the broken line; (3) the circuit breakers on both sides of the line break are tripped together.

And 1.5 for the bus load of the load side transformer substation which is in open-phase operation due to the wire break, automatically transferring by adopting a power supply side or load side breaker of a spare power automatic switching tripping open circuit and closing a spare power supply breaker, and restoring the load to the spare circuit for supplying power. And if the 35kV transformer substation adopts primary main wiring of a 35kV line transformer group, recovering the power supply task by the backup power automatic switching at the low-voltage side of the load side transformer substation.

1.6 the voltage information and the breaker position information on two sides of the line are transmitted through a line optical fiber channel.

2. The operation mode of a 35kV neutral point of a main transformer on a first section or a second section of a bus of a load end 35kV transformer substation is ungrounded; 35kV side equipment 35kV spare power automatic switching device. No. 1 and No. 2 power supply 35kV lines are required to be provided with optical fiber channels and line optical fiber differential protection.

3. The method can be implemented in a 35kV line disconnection protection device independent of a power supply end or a load end 35kV transformer substation or in a 35kV line protection device. The method is implemented in a 35kV line protection device, and has the advantage that no hardware equipment is required to be added.

The setting value of the PT secondary two-side voltage when the buses on the two sides of the 4.35kV line are broken is as follows:

(1) dividing the PT secondary line voltages of a power supply side bus and a load side bus into three groups according to the AB line voltage, the BC line voltage and the CA line voltage for comparison, wherein the PT secondary side voltage amplitude difference setting values are as follows:

1) two of the two sets of the setting values are that the setting value of the difference between the absolute value of the line voltage of the power supply side and the absolute value of the line voltage of the load end meets the following requirements: is greater than or equal to the rated line voltage value

The voltage value of the rated line is less than or equal to 55 percent (1.1 x (1-0.5)), and the voltage value of the PT secondary rated line is 100V, namely more than or equal to 38V and less than or equal to 55V;

2) and the setting value of the difference between the absolute value of the line voltage of the power supply side and the absolute value of the line voltage of the load end of the rest group satisfies the following conditions: less than or equal to 10 percent of rated line voltage value, namely less than or equal to 10V.

(2) The setting value of the PT secondary line voltage of the power supply side bus meets the following requirements: the voltage value of the rated line is more than or equal to 90 percent and less than or equal to 110 percent, namely more than or equal to 90V and less than or equal to 110V.

5. The method of the invention is characterized in that the setting value of time in the single-phase disconnection relay protection method for recovering power supply by the spare power automatic switching of the load-end 35kV transformer substation is as follows:

t 1: and (3) avoiding the three-phase different-period time when the breaker is closed, and taking 0.1-0.2 second.

6. The inventive solution can be used in the following cases: (1) a spare power automatic switching device is arranged on the 35kV side of the 35kV transformer substation; (2) no. 1 and No. 2 power supply 35kV lines are required to be provided with optical fiber channels and line optical fiber differential protection.

And can satisfy the following primary main wiring: (1) a 35kV single-bus subsection primary main wiring of a 35kV transformer substation; (2) a 35kV transformer substation 35kV inner bridge primary main wiring; (3) a 35kV transformer substation 35kV enlarges primary main wiring; (4) a 35kV transformer substation 35kV line group-changing primary main wiring; (5) other primary main connections.

7. For a 35kV line with branch lines, 35kV line breakage protection of pairwise correspondence between a power end-load end substation and each load end substation needs to be implemented.

8. The scheme of the invention for comparing the bus line voltages on two sides of the line can also be used in the case of the disconnection of the 110kV line powered by a single power supply.

An embodiment of the method of the invention is given below, taking fig. 15 and the trip power source side circuit breaker as an example:

operation mode 1:

under this operational mode, 2DL of No. 2 power circuit breaker, the operation of segmentation circuit breaker 3DL, 1DL of No. 1 power circuit breaker is hot standby, 1DL of No. 1 power circuit breaker branch floodgate position promptly.

For example, if phase A is broken, phase B or phase C is broken similarly. When the phase-A single-phase disconnection fault of the No. 2 35kV power line occurs, abnormal operation of the line is sensed through the voltage amplitude difference of 35kV bus lines on two sides, meanwhile, the secondary line voltage of the 35kV bus PT of the power end substation is normal, the single-phase disconnection condition of the No. 2 35kV power line is met, after the time delay t1, the 35kV line in power end line protection is disconnected, and the circuit breaker 5DL on the power side of the No. 2 35kV power line is jumped. Because No. 2 35kV power supply line loses power, 35kV spare power automatic switching action of a load end 35kV transformer substation trips No. 2 kV 35kV power circuit breaker 2DL, and 1 # 35kV spare power circuit breaker 1DL is started to switch on, so that the transformer losing power is recovered to the spare No. 1 kV power supply line for power supply. And reporting the single-phase disconnection fault of the No. 2 35kV power line.

Mode of operation 2

Under this operational mode, 1DL of power breaker, 3DL operation of section circuit breaker, 2 # power breaker 2DL are hot standby, 2 # power breaker 2DL separating brake position promptly.

For example, if phase A is broken, phase B or phase C is broken similarly. When the phase-A single-phase disconnection fault of the No. 1 35kV power line occurs, abnormal operation of the line is sensed through the voltage amplitude difference of 35kV bus lines on two sides, meanwhile, the secondary line voltage of the 35kV bus PT of the power end transformer substation is normal, the single-phase disconnection condition of the No. 1 35kV power line is met, after the time delay t1, the 35kV line in power end line protection is disconnected, and the 4DL of the 1 # 35kV power line power side circuit breaker is jumped. Because No. 1 35kV power line loses the power, the load end 35kV transformer substation 35kV spare power automatic switching action trips No. 1 kV 35kV power circuit breaker 1DL, starts No. 2 kV 35kV spare power circuit breaker 2DL to switch on, makes the transformer that loses the power restore to reserve No. 2 kV power line and supplies power on the way. And reporting the single-phase disconnection fault of the No. 2 35kV power line.

Operation mode 3:

under this operational mode, 1DL of No. 1 power circuit breaker, 2DL of No. 2 power circuit breaker operate, and the hot reserve of section circuit breaker 3DL, section circuit breaker 3DL separating brake position promptly.

No. 1 35kV power line single-phase line break fault

For example, if phase A is broken, phase B or phase C is broken similarly. When the phase-A single-phase disconnection fault of the No. 1 35kV power line occurs, abnormal operation of the line is sensed through the voltage amplitude difference of 35kV bus lines on two sides, meanwhile, the secondary line voltage of the 35kV bus PT of the power end transformer substation is normal, the single-phase disconnection condition of the No. 1 35kV power line is met, after the time delay t1, the 35kV line in power end line protection is disconnected, and the 4DL of the 1 # 35kV power line power side circuit breaker is jumped. Because No. 1 35kV power supply line loses the power, the load end 35kV transformer substation 35kV spare power automatic switching action trips No. 1 kV 35kV power incoming line breaker 1DL, starts the 35kV spare power supply breaker 3DL to close, and the transformer that loses the power is recovered to the spare No. 2 kV power supply line and is supplied power. And simultaneously reporting the single-phase line break fault of the No. 1 35kV power line.

No. 2 35kV power line single-phase line break fault

For example, if phase A is broken, phase B or phase C is broken similarly. When the phase-A single-phase disconnection fault of the No. 2 35kV power line occurs, abnormal operation of the line is sensed through the voltage amplitude difference of 35kV bus lines on two sides, meanwhile, the secondary line voltage of the 35kV bus PT of the power end substation is normal, the single-phase disconnection condition of the No. 2 35kV power line is met, after the time delay t1, the 35kV line in power end line protection is disconnected, and the circuit breaker 5DL on the power side of the No. 2 35kV power line is jumped. Because No. 2 35kV power supply line loses power, 35kV spare power automatic switching of a load end 35kV transformer substation acts, 2DL of a No. 2 kV power supply incoming line breaker is tripped, 3DL of a 35kV spare power supply breaker is started to be switched on, and a transformer losing the power supply is recovered to a spare No. 1 kV power supply line to supply power. And reporting the single-phase disconnection fault of the No. 2 35kV power line.

In addition to the above embodiments, the present invention may have other embodiments, and any technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of the claims of the present invention.

Claims

1. A disconnection protection method for comparing the voltage amplitude difference of two side wires of a circuit with the matching of spare power automatic switching is characterized by comprising the following steps:

1.1 conditions for judging the switch-on of No. 1 line disconnection tripping No. 1 disconnection line power supply side circuit breaker 4DL or load side circuit breaker 1DL and load side backup power supply circuit breaker 2DL or 3DL started by load side backup automatic switch and starting No. 1 line disconnection alarm

Collecting power supply side bus PT secondary AB line voltage value U_A1B1BC line voltage value U_B1C1CA line voltage value U_C1A1Second AB line voltage value U of I section bus PT of load end transformer substation_A2B2BC line voltage value U_B2C2CA line voltage value U_C2A2；

Conditions are as follows: (1) in No. 1 line, the voltage value U of the secondary AB line of the I section bus PT on the power supply side_A1B1Absolute value and load end transformer substation I section bus PT secondary AB line voltage value U_A2B2Difference of absolute value, power source side I section bus PT secondary BC line voltage value U_B1C1Absolute value and load end transformer substation I section bus PT secondary BC line voltage value U_B2C2Difference of absolute value, power source side I section bus PT secondary CA line voltage value U_C1A1Absolute value and load end transformer substation I section bus PT secondary CA line voltage value U_C2A2Of the three differences, two differences being 0.38E_abTo 0.55E_abA difference of 0.1E or less_ab；E_abThe voltage value of a PT secondary side rated line;

(6) the load side breaker 1DL of line No. 1 is in the on position;

if all the conditions are met, identifying and judging that the No. 1 power line is broken, carrying out broken line protection in the line protection of the superior power side transformer substation, and tripping a No. 1 power line power side circuit breaker 4 DL; as the No. 1 power supply circuit loses power supply, the load side circuit breaker 1DL of the No. 1 circuit is started and the standby power supply circuit breaker 2DL or 3DL is closed by the spare power automatic switching action of the load side transformer substation; or the line break protection in the load side transformer substation No. 1 line protection is carried out, and the load side circuit breaker 1DL of the No. 1 line is jumped; as the No. 1 power supply circuit loses power supply, the load end transformer substation is in standby automatic switching action, and the standby power supply breaker 2DL or 3DL is started to be closed; the transformer without power supply is recovered to the standby power line for power supply, and the No. 1 line is started to be off for alarming;

(3) Power end corresponding busPT secondary BC line voltage value U_B1C1Greater than or equal to 0.9E_ab1.1E or less_ab；

(6) the load side breaker 2DL of line No. 2 is in the on position;

if the conditions are all met, identifying and judging that the No. 2 power line is broken, carrying out broken line protection in the line protection of the superior power side substation, and tripping a No. 2 power line power side breaker 5 DL; because the No. 2 power supply circuit loses power supply, the load side circuit breaker 2DL of the No. 2 circuit is started and is tripped, the standby power supply circuit breaker 1DL or 3DL is closed, or the load side circuit breaker 2DL of the No. 2 circuit is tripped by the spare power automatic switching action of the load side transformer substation in the protection of the No. 2 circuit of the load side transformer substation; as the No. 2 power supply circuit loses power supply, the load end transformer substation is in standby automatic switching action, and the standby power supply circuit breaker 1DL or 3DL is started to be closed; the transformer without power supply is recovered to the standby power line for power supply, and the No. 2 line is started to be disconnected for alarm.

2. The method for protecting the disconnection of the line by comparing the voltage amplitude difference between two side wires of the line and the spare power automatic switching device according to claim 1 is applied to a mode that a neutral point of a transformer is not grounded or is grounded through an arc suppression coil or a low-resistance grounding system.

3. The method for protecting the disconnection of the line by comparing the voltage amplitude difference between two side lines of the line and the spare power automatic switching device as claimed in claim 1, wherein the secondary side line voltage value Eab of PT is 100V.