Power distribution network fault detection method and system based on differential analysis and positioning method

Abstract

The invention discloses a power distribution network fault detection method and system based on differential analysis and a positioning method. The method comprises the steps: constructing a correction rule of a fault feature value based on the fault current feature analysis of a DC power distribution network; acquiring a first parameter of the DC power distribution network in a normal operation state; constructing a fault identification criterion and a protection starting criterion based on the first parameter and a correction rule of the fault feature value; acquiring a second parameter of the DC power distribution network in the fault state; and based on the fault identification criterion and the protection starting criterion, judging whether the second parameter satisfies the fault identification criterion and the protection starting criterion, and if the second parameter satisfies the fault identification criterion and the protection starting criterion, judging that the fault of the DC power distribution network is the internal fault. The method has the beneficial effects that the fault and the type of the fault can be quickly identified, and the reliability, the quickness and the selectivity of the detection result are good; and the fault current differential value is compensated and corrected by utilizing the correction strategy, and the anti-transition resistance capability and the sensitivity of protection are improved.

Description

technical field

[0001] The invention relates to the technical field of distribution network fault detection, in particular to a distribution network fault detection method, system and positioning method based on differential analysis. Background technique

[0002] With the continuous development of distributed power sources with clean energy such as wind energy and solar energy as the core and electric vehicles, the power supply requirements of the distribution network are becoming more and more stringent. Among them, the DC distribution network has become a key direction for the development of the current distribution network because of its outstanding advantages in transmission capacity, line loss, power quality, and ease of access to distributed power and energy storage. However, due to the small damping and large capacity of the DC distribution network, the fault current changes rapidly within a few milliseconds after a fault, and the protection requirements for the DC d...

Examples

Embodiment 1

[0071] This embodiment discloses a distribution network fault detection method based on differential analysis, such as figure 1 As shown, it is applied to a DC distribution network connected to a current-limiting reactor, and the detection method steps include:

[0072] S1: Based on the analysis of the fault current characteristics of the DC distribution network, the correction rules for the fault characteristic value are constructed;

[0073] Analyze the fault characteristics of the DC distribution network with current-limiting reactors, design the fault eigenvalue correction rules for DC distribution networks with current-limiting reactors, and construct fault identification for DC distribution networks with current-limiting reactors based on the correction rules Criterion, the purpose of modifying the rules is to improve the protection's tolerance to transition resistance and improve the sensitivity of protection. The theoretical reason is that although the current limiting...

Embodiment 2

[0119] This implementation discloses a distribution network fault location method based on differential analysis, such as figure 1 As shown, it is applied to the DC distribution network detected by the detection method in the first embodiment as an intra-area fault, and the positioning method is:

[0120] Judging the relationship between the ratio K of the fault positive line current differential value to the fault negative line current differential value and the setting value of the fault pole selection criterion within the rated time, the specific judgment method is:

[0121]

[0122] K set It is the setting value of fault pole selection criterion. The fault pole selection criterion is designed to judge the type and location of the fault. The basis for the design of the fault selection criterion is that the ratio K of the differential value of the positive line current differential value to the negative line current differential value within the rated time has an obviou...

Embodiment 3

[0142] This embodiment discloses a distribution network fault detection system based on differential analysis. This embodiment implements the detection method in Embodiment 1, including a rule construction module, a first parameter acquisition module, a criterion construction module, and a second parameter acquisition module. and fault judgment module,

[0143] The rule building module is used to construct a correction rule for fault characteristic values ​​based on the fault current characteristic analysis of the DC distribution network;

[0144] The first parameter acquisition module is used to acquire the first parameters of the DC distribution network under normal operating conditions, the first parameters include the positive line current differential value, the negative line current differential value, the positive line voltage to ground and the negative line current differential value. line-to-earth voltage;

[0145] The criterion construction module is configured to c...

technical field

[0001] The invention relates to the technical field of distribution network fault detection, in particular to a distribution network fault detection method, system and positioning method based on differential analysis. Background technique

[0002] With the continuous development of distributed power sources with clean energy such as wind energy and solar energy as the core and electric vehicles, the power supply requirements of the distribution network are becoming more and more stringent. Among them, the DC distribution network has become a key direction for the development of the current distribution network because of its outstanding advantages in transmission capacity, line loss, power quality, and ease of access to distributed power and energy storage. However, due to the small damping and large capacity of the DC distribution network, the fault current changes rapidly within a few milliseconds after a fault, and the protection requirements for the DC d...

Examples

Embodiment 1

[0071] This embodiment discloses a distribution network fault detection method based on differential analysis, such as figure 1 As shown, it is applied to a DC distribution network connected to a current-limiting reactor, and the detection method steps include:

[0072] S1: Based on the analysis of the fault current characteristics of the DC distribution network, the correction rules for the fault characteristic value are constructed;

[0073] Analyze the fault characteristics of the DC distribution network with current-limiting reactors, design the fault eigenvalue correction rules for DC distribution networks with current-limiting reactors, and construct fault identification for DC distribution networks with current-limiting reactors based on the correction rules Criterion, the purpose of modifying the rules is to improve the protection's tolerance to transition resistance and improve the sensitivity of protection. The theoretical reason is that although the current limiting...

Embodiment 2

[0119] This implementation discloses a distribution network fault location method based on differential analysis, such as figure 1 As shown, it is applied to the DC distribution network detected by the detection method in the first embodiment as an intra-area fault, and the positioning method is:

[0120] Judging the relationship between the ratio K of the fault positive line current differential value to the fault negative line current differential value and the setting value of the fault pole selection criterion within the rated time, the specific judgment method is:

[0121]

[0122] K set It is the setting value of fault pole selection criterion. The fault pole selection criterion is designed to judge the type and location of the fault. The basis for the design of the fault selection criterion is that the ratio K of the differential value of the positive line current differential value to the negative line current differential value within the rated time has an obviou...

Embodiment 3

[0142] This embodiment discloses a distribution network fault detection system based on differential analysis. This embodiment implements the detection method in Embodiment 1, including a rule construction module, a first parameter acquisition module, a criterion construction module, and a second parameter acquisition module. and fault judgment module,

[0143] The rule building module is used to construct a correction rule for fault characteristic values ​​based on the fault current characteristic analysis of the DC distribution network;

[0144] The first parameter acquisition module is used to acquire the first parameters of the DC distribution network under normal operating conditions, the first parameters include the positive line current differential value, the negative line current differential value, the positive line voltage to ground and the negative line current differential value. line-to-earth voltage;

[0145] The criterion construction module is configured to c...

Images