CN102611084B - Self-adaptive voltage protection method - Google Patents

Abstract

The invention discloses a self-adaptive voltage protection method in the technical field of electric systems. The method includes: setting up an original system database; constructing a self-adaptive voltage main protection for a distribution network according to the relation between phase current and phase voltage difference before and after failure, and working out a setting value and a measured value of the voltage main protection, wherein when the setting value of the voltage main protection is smaller than the measured value, the main protection does not act, and otherwise, the main protection trips out; and constructing a self-adaptive voltage back-up protection according to the relation between phase current and phase voltage difference before and after failure, and working out a setting value and a measured value of the voltage back-up protection, wherein when the setting value of the voltage back-up protection is smaller than the measured value, the back-up protection does not act, and otherwise, the back-up protection trips out. Real-time adjustment according to variation of operating ways of electric systems and fault types is realized, and accordingly the protection can be operated reliably under the condition of symmetrical faults and asymmetric faults.

Description

A kind of adaptive voltage guard method

Technical field

The invention belongs to technical field of power systems, relate in particular to a kind of adaptive voltage guard method.

Background technology

Traditional relay protection is to calculate definite value under electric power system maximum operational mode, and under minimum operational mode, the mode of verification sensitivity is carried out off-line setting calculation, and protection definite value is protected all the time constant in running.But, when electric power system is during in non-maximum operational mode, non-best setting value of protection definite value, traditional relay protection also cannot reach best protection effect.When electric power system is during in minimum operational mode, traditional relay protection even can lose efficacy.Given this, some experts and scholars have proposed the concept of adaptive guard, can change in real time according to the variation of power system operation mode and malfunction the protection of protective value, characteristic or definite value.

In recent years, along with the access of distributed power source (DG), the operational mode of electrical network becomes more flexible, and it is further outstanding that the contradiction between selectivity, sensitivity and the reliability of adaptive guard also shows.

Summary of the invention

Can not change with power system operation mode for the traditional relay protection of mentioning in above-mentioned background technology, cause protecting poor effect or the deficiency that lost efficacy, the present invention proposes a kind of adaptive voltage guard method.

Technical scheme of the present invention is that a kind of adaptive voltage guard method, is characterized in that the method comprises the following steps:

Step 1: build original system data storehouse;

Step 2: obtain the setting value of voltage main protection and the measured value of voltage main protection, in the time that main protection setting value is less than measured value, main protection is failure to actuate; In the time that main protection setting value is greater than measured value, main protection outlet tripping operation;

Step 3: obtain the setting value of voltage backup protection and the measured value of backup protection, in the time that backup protection setting value is less than measured value, backup protection is failure to actuate; In the time that backup protection setting value is greater than measured value, backup protection outlet tripping operation.

The computing formula of the setting value of described main protection is:

$U_{\mathrm{set}1}=k_d{k}_{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000142481690000031.png,HDA0000142481690000032.png"\; state="\{\{state\}\}">r</figure-callout>}1}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\right|\left|Z_{\mathrm{mn}}\right|$

Wherein:

U _set1for the setting value of main protection;

K _dfor fault type coefficient;

K _r1for the safety factor of adaptive voltage main protection

for the phase current of measuring at bus M place; ;

Z _mnfor the impedance of circuit MN.

The computing formula of the measured value of described main protection is:

$U_{\mathrm{<figure-callout\; id="1"\; label="m"\; filenames="HDA0000142481690000031.png,HDA0000142481690000032.png"\; state="\{\{state\}\}">m</figure-callout>}1}=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|$

Wherein:

U _m1for the measured value of main protection;

be respectively any two fault phase voltages at bus M place.

The computing formula of the setting value of described backup protection is:

$U_{\mathrm{set}2}=k_d\left(k_{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">r</figure-callout>}2}\right|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\left|\right|Z_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}\left|\right|Z_{\mathrm{jm}}\left|\right)$

Wherein:

U _set2for the setting value of backup protection;

K _dfor fault type coefficient;

K _r2for self adaptation backup protection safety factor;

for the phase current of measuring at bus J place;

Z _jmfor the impedance of circuit JM.

The computing formula of the measured value of described backup protection is:

$U_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">m</figure-callout>}2}=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|+|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}|$

Wherein:

U _m2for the measured value of backup protection;

for any two fault phase voltages of IED3 measurement;

for the corresponding phase fault voltage of IED1 measurement.

The present invention has the following advantages:

1. the present invention need not make a concrete analysis of type, on-position, quantity, capacity, operational mode and the control mode of distributed power source, has avoided accessing the protective relaying maloperation causing and doing due to distributed power source the generation of situation.

2. protection setting value is adjusted in real time along with the operational mode of system and the variation of fault type, makes this protection all can action message under symmetric fault and unbalanced fault, has realized the adaptation function of voltage protection.

3. the protection range of main protection is not subject to the impact of fault type, even under the rough sledding of two-phase phase fault, its protection range still can approach 90% of this circuit.Compared with conventional voltage protection, the protection range of adaptive voltage main protection has obtained effective extension.

4. the protection range of backup protection is not subject to the impact of fault type; backup protection not only can extend to 80% left and right of subordinate's protection circuit; and in view of the protection range of main protection is 90% of total track length; therefore; the protection range that backup protection extends to subordinate's circuit is less than the protection range of main protection, can meet the requirement that protection coordinates.

Brief description of the drawings

Fig. 1 is simple supply network schematic diagram;

Fig. 2 is Digital Simulation test macro schematic diagram;

Fig. 3 is distributed power source (DG) control mode figure schematic diagram;

The operating characteristics schematic diagram of main protection when three-phase fault in Tu4Wei district;

The operating characteristics schematic diagram of main protection when phase to phase fault in Tu5Wei district;

The operating characteristics schematic diagram of backup protection when three-phase fault in Tu6Wei district;

The operating characteristics schematic diagram of backup protection when phase to phase fault in Tu7Wei district.

Embodiment

Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that, following explanation is only exemplary, instead of in order to limit the scope of the invention and to apply.

The technical problem to be solved in the present invention is: in the case of position, quantity and capacity without the access of consideration distributed power source; utilize the centralized wide area protection system of finite region to form a kind of electric power system adaptive voltage new protective method, reach the adaptive guard object containing the intelligent grid of distributed power source.

The present invention solves the technical scheme that its technical problem is taked: utilize the centralized wide area protection system storage of finite region line related parameter; communication between the relevant IED of Real-time Obtaining voltage, current information and realization; on this basis; the relation of and phase current poor according to phase voltage before and after fault, has constructed the main protection of power distribution network adaptive voltage and adaptive voltage backup protection.

Below specifically introduce content of the present invention; the present invention mainly utilizes the centralized wide area protection system storage of finite region line related parameter; communication between the relevant IED of Real-time Obtaining voltage, current information and realization; on this basis; the relation of and phase current poor according to phase voltage before and after fault, constructs the main protection of novel power distribution network adaptive voltage and adaptive voltage backup protection.

Step 1 initialization

Build original system data storehouse, collection capacity comprises:

1) system node (bus): gather content and comprise node serial number, node voltage size, phase place etc.

2) circuit: gather resistance value, the type of circuit and the load current of each circuit etc. that content comprises circuit two ends node serial number, circuit.

3) generator: gather the situation of change etc. of exerting oneself that content comprises node serial number that generator connects, generator.

4) simulation type: circuit, fault type, the fault breaking down occurs and remove moment, simulation time parameter etc. in the moment.

5) distributed power source: content comprises type, capacity, on-position, quantity, control mode and the real time operation mode etc. of distributed power source.

6) load: content comprises load type, size, load variations situation etc.

Step 2 is obtained setting value and the measured value of novel voltage main protection

In simple supply network as shown in Figure 1, the generator that bus J, M, N connect represents respectively equivalent electric power system, and F point is fault point, and the impedance of circuit MN, JM is respectively Z _mn, Z _jm, the impedance of circuit MF is α Z _mn, because F point is not fixed, therefore the value of factor alpha is 0 to 1.

In the time there is three-phase fault in F point, the three-phase fault voltage that IED3 measures meet following relation:

$|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}1}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(3\right)}|=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(3\right)}|=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}1}^{\left(3\right)}|---\left(1\right)$

Taking φ 2, φ 3, mutually as example, formula (1) is deployable is:

$\begin{array}{c}|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(3\right)}|=|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}2}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}3}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}|\\ =\sqrt{3}\mathrm{\&alpha;}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}^{\left(3\right)}\right|\left|Z_{\mathrm{mn}}\right|\end{array}---\left(2\right)$

In formula, be respectively φ 2, φ 3 phase currents that in three-phase fault situation, IED3 measures, for the fault phase electric current of IED3 measurement in three-phase fault situation.

In the time there is φ 2 φ 3 phase-to phase fault in F point, φ 2, φ 3 phase fault voltages that IED3 measures

total satisfied:

$|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(2\right)}|=\left|({\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}3}^{\left(2\right)})\mathrm{\&alpha;}{Z}_{\mathrm{mn}}\right|=\sqrt{3}\mathrm{\&alpha;}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}^{\left(3\right)}\right|\left|Z_{\mathrm{mn}}\right|---\left(3\right)$

In formula,

be respectively φ 2, φ 3 phase currents that in φ 2 φ 3 phase-to phase fault situations, IED3 measures.

Generally, the positive and negative order current distribution factor of circuit is equal, and formula (3) also can be write as:

$|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(2\right)}|=\left|({\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}3}^{\left(2\right)})\mathrm{\&alpha;}{Z}_{\mathrm{mn}}\right|=2\mathrm{\&alpha;}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}^{\left(2\right)}\right|\left|Z_{\mathrm{mn}}\right|---\left(4\right)$

In formula,

for the fault phase electric current of IED3 measurement in φ 2 φ 3 phase-to phase fault situations.

In the time that system is normally moved,

for the φ 2 at bus M place, the line voltage of φ 3, can further be expressed as:

$|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|=\sqrt{3}\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}}\right|---\left(5\right)$

In formula,

represent the phase voltage at bus M place.

The measured value U of the adaptive voltage main protection of definition circuit MN _m1:

${\mathrm{<figure-callout\; id="1"\; label="U\; m"\; filenames="HDA0000142481690000031.png,HDA0000142481690000032.png"\; state="\{\{state\}\}">U</figure-callout>}}_m=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|---\left(6\right)$

In formula,

for any two fault phase voltages at bus M place.

The setting value U of the adaptive voltage main protection of definition circuit MN _set1:

$U_{\mathrm{set}1}=k_{\mathrm{<figure-callout\; id="1"\; label="d\; k\; r"\; filenames="HDA0000142481690000031.png,HDA0000142481690000032.png"\; state="\{\{state\}\}">d</figure-callout>}}{k}_r{1}_{}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\right|\left|Z_{\mathrm{mn}}\right|---\left(7\right)$

In formula, k _r1for the safety factor of adaptive voltage main protection, get 0.9.

the phase current of measuring at the bus M IED3 of place.K _dfor fault type coefficient, when three-phase fault, get

when phase-to phase fault, get 2, while normally operation, get 1.

In the time that system is normally moved, known according to formula (7), main protection setting value

wherein, for phase voltage difference between bus M and bus N, can be expressed as

the circuit both end voltage difference in magnitude of considering normal operation is little, and for keeping stability of power system, circuit two ends phase angle difference is generally not more than 90 degree.Therefore, have set up.Now, main protection measured value is represented by formula (5), analyzes known: before fault, the setting value of adaptive voltage main protection is less than its measured value, and protection is correctly failure to actuate.

In the time that F point breaks down, in formula (7)

change fault current into by load current, its value enlarges markedly.So main protection setting value also significantly rises, and only difference to some extent on coefficient of the main protection measured value expression formula shown in its expression formula and formula (2) and formula (4).Known by analyzing: no matter three-phase fault or phase-to phase fault to occur, as α < k _r1time, all there is U _set1> U _m1, main protection action; As α > k _r1time, all there is U _set1< U _m1, main protection is failure to actuate; As α=k _r1time, there is U _set1=U _m1set up.,, in the time that main protection setting value is less than measured value, main protection is failure to actuate; In the time that main protection setting value is greater than measured value, main protection outlet tripping operation.The protection range that can determine thus adaptive voltage main protection is α=k _r1=90%.

Adaptive voltage main protection only utilizes voltage, the current information of protection installation place, has avoided the communication delay of wide area protection system, meets the quick-action requirement of main protection.

For correctness is described, the present invention has carried out a large amount of Digital Simulations in the system shown in Fig. 2.The reference capacity of this power distribution network is 500MVA, and reference voltage is 10.5kV.Wherein, line parameter circuit value refers to table 1.The rated power of load is 6MVA, and rated power factor is 0.85.Distributed power source (DG) is connected on bus C place, and its rated power is 11MVA, adopts current mode PQ control mode, as shown in Figure 3.

The network parameter of certain 10.5kV power distribution network in table 1 Tianjin Power Grid

Setting method taking protection R3 as the main protection of example explanation adaptive voltage herein.Main protection setting value and the measured value of protection R3 are respectively V _ps3and V _pm3.

In simulation process, system is in maximum operational mode, and DG exerts oneself as 2.75MVA, and fault all occurs in the T=0.30s moment, and disappears in the T=0.80s moment.When circuit CD mid point (in main protection district) occurs in three-phase shortcircuit situation, the main protection self adaptation operating characteristics curve of protection R3 as shown in Figure 4.When circuit CD mid point (in main protection district) occurs in two-phase phase fault situation, the main protection self adaptation operating characteristics curve of protection R3 as shown in Figure 5.

Can find out by Fig. 4 and Fig. 5, in fault occurs in main protection district time, the measured value V of the adaptive voltage main protection of protection R3 _pm3all reduce rapidly, meanwhile, the setting value V of adaptive voltage main protection _ps3increase rapidly.When measured value is during lower than setting value, main protection is moved immediately.

Table 2 is protected setting value and the measured value of the adaptive voltage main protection of R3

Table 2 is the protection R3 adaptive voltage main protection simulation result of different faults position.As shown in Table 2, even under the rough sledding of two-phase phase fault, the protection range of adaptive voltage main protection still can reach 90% of this circuit.

Step 3 is obtained setting value and the measured value of novel voltage backup protection

For the backup protection that is arranged on bus J place, first rely on wide area protection system to introduce the measured current of IED1, IED2, and adopt the nearly backup protection of wide area differential protection as circuit JM.Upper if fault occurs in circuit JM, and the main protection of IED1 place do not move, and wide area differential protection is without deferred action, and be only the wide-area communication time its operate time.In addition,, in order to prevent the protection of IED3 place or circuit breaker tripping, adopt the adaptive voltage backup protection that realizes with the following method circuit MN.

The measured value U of the adaptive voltage backup protection of definition circuit MN _m2:

${\mathrm{<figure-callout\; id="2"\; label="U\; m"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_m=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|+|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}|---\left(8\right)$

In formula,

for any two fault phase voltages of IED3 measurement, and pass to IED1;

for the corresponding phase fault voltage of IED1 measurement.

The setting value U of the adaptive voltage backup protection of definition circuit MN _set2:

$U_{\mathrm{set}2}=k_d\left({\mathrm{<figure-callout\; id="2"\; label="k\; r"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_r\right|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\left|\right|Z_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}\left|\right|Z_{\mathrm{jm}}\left|\right)---\left(9\right)$

In formula, k _r2for self adaptation backup protection safety factor, get 0.8.K _dfor fault type coefficient, when three-phase fault, get

when phase-to phase fault, get 2, while normally operation, get 1.

for the phase current of measuring at the bus J IED1 of place.

In the time that system is normally moved, known according to formula (9), the setting value of the adaptive voltage backup protection of circuit MN is:

$U_{\mathrm{set}2}={\mathrm{<figure-callout\; id="2"\; label="k\; r"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_r\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\right|\left|Z_{\mathrm{mn}}\right|+\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}\right|\left|Z_{\mathrm{jm}}\right|---\left(10\right)$

In the time that system is normally moved, in the adaptive voltage backup protection setting value expression formula (10) of circuit MN

be load current, and have $\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}\right|\left|Z_{\mathrm{jm}}\right|=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}}|<\sqrt{3}\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}}\right|,$ ${\mathrm{<figure-callout\; id="2"\; label="k\; r"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_r\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\right|\left|Z_{\mathrm{mn}}\right|={\mathrm{<figure-callout\; id="2"\; label="k\; r"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_r|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{N\&phi;}}|<\sqrt{3}\left|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}}\right|$ Set up.Meanwhile, the adaptive voltage backup protection measured value of circuit MN is

therefore, before fault, the setting value of adaptive voltage backup protection is less than its measured value, and protection is correctly failure to actuate.

In the time there is three-phase fault in F point, φ 1, φ 2, φ 3 three-phase fault voltages that IED1 measures

meet following relation:

$|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}1}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}^{\left(3\right)}|=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}^{\left(3\right)}|=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}1}^{\left(3\right)}|---\left(11\right)$

Taking φ 2, φ 3, mutually as example, in the time that three-phase fault occurs F point, the measured value expression formula of the adaptive voltage backup protection of the circuit MN shown in formula (8) is deployable is:

${\mathrm{<figure-callout\; id="2"\; label="U\; m"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_m=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(3\right)}|+|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}^{\left(3\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}^{\left(3\right)}|$

$=|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}2}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}3}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}2}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}3}^{\left(3\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}|---\left(12\right)$

$=\sqrt{3}\left(\mathrm{\&alpha;}\right|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}^{\left(3\right)}\left|\right|Z_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}^{\left(3\right)}\left|\right|Z_{\mathrm{jm}}\left|\right)$

In formula,

φ 2, φ 3 phase currents that while being respectively three-phase fault, IED1 measures,

the fault phase electric current that during for three-phase fault, IED1 measures.

In the time that φ 2 φ 3 phase-to phase fault occurs F point, the adaptive voltage backup protection measured value expression formula of the circuit MN shown in formula (8) is deployable is:

${\mathrm{<figure-callout\; id="2"\; label="U\; m"\; filenames="HDA0000142481690000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_m=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(2\right)}|+|({\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}^{\left(2\right)})-({\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}^{\left(2\right)}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}^{\left(2\right)})|$

$=|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}2}^{\left(2\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}3}^{\left(2\right)}\mathrm{\&alpha;}{Z}_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}2}^{\left(2\right)}{Z}_{\mathrm{jm}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}3}^{\left(2\right)}{Z}_{\mathrm{jm}}|---\left(13\right)$

$=2\left(\mathrm{\&alpha;}\right|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}^{\left(2\right)}\left|\right|Z_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}^{\left(2\right)}\left|\right|Z_{\mathrm{jm}}\left|\right)$

In formula,

φ 2, φ 3 phase currents that while being respectively φ 2 φ 3 phase-to phase fault, IED1 measures,

the fault phase electric current that during for φ 2 φ 3 phase-to phase fault, IED1 measures.

In the time that F point breaks down, in formula (9)

become fault current by load current, enlarging markedly of its value caused adaptive voltage backup protection setting value fast rise.Known by contrast (9) and formula (12), formula (13); the setting value expression formula of adaptive voltage backup protection and its measured value expression formula are basic identical; only difference to some extent on coefficient; and no matter there is three-phase fault or phase-to phase fault, all just like the establishment of drawing a conclusion: as α < k _r2time, U _set2> U _m2, backup protection action; As α > k _r2time, U _set2< U _m2, backup protection is failure to actuate; As α=k _r2time, U _set2=U _m2.,, in the time that backup protection setting value is less than measured value, backup protection is failure to actuate; In the time that backup protection setting value is greater than measured value, backup protection outlet tripping operation.Can determine that thus the protection range that adaptive voltage backup protection can extend to subordinate's circuit is α=k _r2=80%.In addition, the protection range of this adaptive voltage backup protection is less than the protection range of adaptive voltage main protection, meets the requirement of protection selectivity.

For correctness is described, the present invention has carried out a large amount of Digital Simulations in the system shown in Fig. 2.The adjusting and matching relationship as example explanation adaptive voltage protection taking protection R3 and R2.Main protection setting value and the measured value of protection R3 are respectively V _ps3and V _pm3, the backup protection setting value of protection R2 and measured value V respectively _bs2and V _bm2.

In the time that circuit CD is upper and break down near bus C place (in backup protection district), if the adaptive voltage main protection of protection R3 is failure to actuate, protect R2 to provide adaptive voltage backup protection for circuit CD.Fig. 6 and Fig. 7 are respectively in three-phase shortcircuit and two-phase phase fault situation, the self adaptation operating characteristics curve of the backup protection of protection R2.

Can be found out by Fig. 6 and Fig. 7 no matter which kind of type fault (symmetric fault or unbalanced fault) occurs, the backup protection measured value V of protection R2 _bm2all be less than its setting value V _bs2, protection R2 can realize the self adaptation backup protection function of circuit MN.

Table 3 is protected setting value and the measured value of the adaptive voltage backup protection of R2

Table 3 is the protection R2 adaptive voltage backup protection simulation result of different faults position.As shown in Table 3, even under the rough sledding of two-phase phase fault, the protection range of adaptive voltage backup protection can extend to 80% of subordinate's circuit, and can match with adaptive voltage main protection, meets protection selectivity.

For the access of verification system operational mode and DG and exert oneself and change the impact on adaptive voltage protection, in the situation that changing system operation mode and DG and exerting oneself, carry out a large amount of simulating, verifyings herein.Wherein, when breaking down on circuit CD, and the distance of fault point and bus C is total track length when 90% (main protection end), and protection R3 adaptive voltage main protection simulation result is as shown in table 4; When breaking down on circuit CD, and the distance of fault point and bus C is total track length when 80% (backup protection end), and protection R2 adaptive voltage backup protection simulation result is as shown in table 5.

Table 4 different system operational mode and DG exert oneself and protect the adaptive voltage main protection of R3 in situation

Table 5 different system operational mode and DG exert oneself and protect the adaptive voltage backup protection of R2 in situation

A large amount of simulating, verifyings show; the variation that the definite value of adaptive voltage protection is exerted oneself along with power distribution network operational mode and distributed power source and automatically adjusting; but no matter which kind of fault (symmetric fault or unbalanced fault) occurs, and adaptive voltage main protection and backup protection are not all subject to the access of power system operation mode and distributed power source and exert oneself the impact changing.

The inventive method is utilized the centralized wide area protection system storage of finite region line related parameter; communication between the relevant IED of Real-time Obtaining voltage, current information and realization; on this basis; the relation of and phase current poor according to phase voltage before and after fault, has constructed adaptive voltage main protection and adaptive voltage backup protection.Simulation result shows that this adaptive guard can be according to the variation of system operation mode and fault type and automatically adjust in real time definite value; not accessed by distributed power source (DG) and the impact changing of exerting oneself, effectively extended the protection range of conventional voltage protection.

The present invention adopts the centralized wide area protection system storage of finite region line related parameter; communication between the relevant IED of Real-time Obtaining voltage, current information and realization; on this basis; the relation of and phase current poor according to phase voltage before and after fault, has constructed the main protection of power distribution network adaptive voltage and adaptive voltage backup protection.Adopt the protection of fault steady-state component theory building New type of current.

The above; only for preferably embodiment of the present invention, but protection scope of the present invention is not limited to this, is anyly familiar with in technical scope that those skilled in the art disclose in the present invention; the variation that can expect easily or replacement, within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims (1)

1. an adaptive voltage guard method, is characterized in that the method comprises the following steps:

Step 1: build original system data storehouse;

Step 2: obtain the setting value of voltage main protection and the measured value of voltage main protection, in the time that main protection setting value is less than measured value, main protection is failure to actuate; In the time that main protection setting value is greater than measured value, main protection outlet tripping operation;

The computing formula of the setting value of described main protection is:

$U_{\mathrm{set}1}=k_d{k}_{r1}\left|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\right|\left|Z_{\mathrm{mn}}\right|$

Wherein:

U _set1for the setting value of main protection;

K _dfor fault type coefficient;

K _r1for the safety factor of adaptive voltage main protection;

for the phase current of measuring at bus M place;

Z _mnfor the impedance of circuit MN;

The computing formula of the measured value of described main protection is:

$U_{m1}=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|$

Wherein:

U _m1for the measured value of main protection;

be respectively any two fault phase voltages at bus M place;

Step 3: obtain the setting value of voltage backup protection and the measured value of backup protection, in the time that backup protection setting value is less than measured value, backup protection is failure to actuate; In the time that backup protection setting value is greater than measured value, backup protection outlet tripping operation;

The computing formula of the setting value of described backup protection is:

$U_{\mathrm{set}2}=k_d\left(k_{r2}\right|{\stackrel{\&CenterDot;}{I}}_{\mathrm{M\&phi;}}\left|\right|Z_{\mathrm{mn}}|+|{\stackrel{\&CenterDot;}{I}}_{\mathrm{J\&phi;}}\left|\right|Z_{\mathrm{jm}}\left|\right)$

Wherein:

U _set2for the setting value of backup protection;

K _dfor fault type coefficient;

K _r2for self adaptation backup protection safety factor;

for the phase current of measuring at bus J place;

Z _jmfor the impedance of circuit JM;

The computing formula of the measured value of described backup protection is:

$U_{m2}=|{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{M\&phi;}3}|+|{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}2}-{\stackrel{\&CenterDot;}{U}}_{\mathrm{J\&phi;}3}|$

Wherein:

U _m2for the measured value of backup protection;

be respectively any two fault phase voltages that IED3 measures; IED3 is positioned on subordinate's circuit of backup protection place circuit;

be respectively the corresponding phase fault voltage that IED1 measures; IED1 is positioned at backup protection institute on the line.

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