JP4008372B2

JP4008372B2 - High temperature operation type secondary battery system with both load leveling function and uninterruptible power supply function

Info

Publication number: JP4008372B2
Application number: JP2003082012A
Authority: JP
Inventors: 浩幸阿部; 卓夫伊丹
Original assignee: NGK Insulators Ltd; Toshiba Mitsubishi Electric Industrial Systems Corp
Current assignee: NGK Insulators Ltd; Toshiba Mitsubishi Electric Industrial Systems Corp
Priority date: 2003-03-25
Filing date: 2003-03-25
Publication date: 2007-11-14
Anticipated expiration: 2023-03-25
Also published as: JP2004289980A

Description

【０００１】
【発明の属する技術分野】
本発明は、負荷平準化機能及び無停電電源機能を併せ持ち、通常は負荷平準化機能を発揮するとともに、停電発生時には無停電電源機能を発揮し瞬低乃至停電を補償すべく負荷へ電力供給し得る高温作動型二次電池システムに関する。
【０００２】
【従来の技術】
多くの場合、工場は昼間に稼動し夜間は停止するか操業率を低下させる。又、通常、オフィスで人が働く時間も昼間である。従って、昼夜間の電力負荷の格差は大きくなる。更に、冷暖房なしに過ごし易い春秋に比べて、夏冬には猛暑乃至厳寒のため冷房や暖房の需要が増加することから、電力負荷は季節によっても格差を生じ得る。近年、これらの格差は益々拡大してきており、電力供給設備の稼働率を表す負荷率は年々低下してきている。一方で、産業競争力を向上させる目的等により電力コストを低減する要望は高まってきており、電力供給にかかる負荷平準化は大変重要な課題と考えられている。そして、その対策の１つとして、高効率で大容量な二次電池の開発が進められ、負荷状態によって充放電を行い電力供給設備からみた負荷変動を抑え得る電池電力貯蔵システムとして実用化されている。
【０００３】
又、現代社会では、高度に発達したコンピュータシステムと通信ネットワークを用いたオンラインシステムが広く浸透し、それらコンピュータシステムや通信ネットワークにより重要な生産設備等が制御・稼動されている。従って、供給電力に瞬低（電圧低下）や停電が生じれば、各種サービスや製品等に大きな損失を与えかねず、電力供給系の品質の安定は大変重要な課題である。そして、その対策として無停電電源装置の設置が有効であり、二次電池を電力供給源とする無停電電源装置がよく知られている。
【０００４】
上記したように、負荷平準化を実現するためにも供給電力の品質を安定させるためにも二次電池が有用である。そこで、従来より、同一の二次電池を電力貯蔵供給源として負荷平準化機能と無停電電源機能を併せ持つシステムの提案がなされている。例えば、株式会社ＮＴＴファシリティーズのパンフレット（ＮＴＴＦ３０８０Ａ０１０９）［電力貯蔵システム］や日本碍子株式会社のパンフレット（２００２年９月発行）「ＮＡＳ電池電力貯蔵システム」、東京電力株式会社のリーフレット「ＵＰＳ兼用（２００ｋＷ級）ＮＡＳ電池」によれば、常時インバータ方式の無停電電源装置において、負荷平準化機能と無停電電源機能を併せ持つシステム構成が明記されている。又、図３に構成が示される二次電池システムが知られている。
【０００５】
二次電池システム３０は、主に二次電池１３を電力供給源とする常時インバータ給電方式の無停電電源装置３１を主構成要素とする。その無停電電源装置３１は、直流電源に相当する交直変換器４３と、直交変換器５１（インバータ）とを必須の構成要素としてなり、高速切替スイッチ４１と変圧器９、及び、電力系統６に接続された無瞬断バイパス回路４７と保守バイパス回路４８を有する装置である。
【０００６】
二次電池システム３０では、常時は、高圧（例えば６．６ｋＶ）の電力系統１から供給される交流電力が、変圧器９で低圧（例えば２１０Ｖ）に降圧され、交直変換器４３で直流電力に変換され、二次電池１３を充電しながら直交変換器５１に供給され、直交変換器５１により再び交流電力に変換され、負荷２に供給される。あるいは、二次電池１３が放電モードの場合は、電池出力の一部又は全部が負荷２に供給される。
【０００７】
そして、電力系統１が停電すると、二次電池１３から直流電力が放電され、直交変換器５１に供給されるので、直交変換器５１から瞬断なく負荷２に交流電力が供給される。このようにして、二次電池システム３０は、無停電電源機能を実現する。又、二次電池システム３０は、交直変換器４３を双方向変換可能とすることで、負荷平準化系統側に電力を流し込むことが可能となり、負荷平準化機能を大きく生かすことが出来る。
【０００８】
しかしながら、二次電池システム３０では、系統連系技術要件ガイドライン（旧通商産業省／資源エネルギー庁平成１０年改正）に基づき、何らかの原因により連系保護リレー４４が動作したときは、一旦、系統連系システムである二次電池システムとして連系遮断器１０１を開放し、電力系統１から解列する必要がある。連系遮断器１０１が解列されると、二次電池１３から放電を開始し、連系保護リレー４４が復帰した後に、自動で再起動し元の状態に復帰することにより、原理的には負荷２に瞬低を生じることはない。しかし、連系保護リレー４４が動作したときに電力系統から解列しなければならないために、万一、連系保護リレー４４が故障した場合にはシステムを再起動させることが出来ず、無停電電源機能としての信頼性が損なわれる場合がある。これは、負荷２が特に重要な設備である場合には重大な問題になり得る。
【０００９】
【発明が解決しようとする課題】
本発明は、上記した問題を生じ得ない二次電池システムを提供することを課題とする。より具体的に本発明の目的とするところは、負荷平準化機能と無停電電源機能とを併せ持つとともに、系統連系技術要件ガイドラインに従い連系保護リレーが動作したときに電力系統から系統連系システムを解列可能であり、且つ、万一、連系保護リレーが故障した場合も無停電電源機能を喪失することのない、より信頼性の高い二次電池システムを提供することにある。従来の二次電池システムの構成について見直し検討がなされ、二次電池を共有しつつ、負荷平準化機能を発現する部分（負荷平準化機能部）と無停電電源機能を発現する部分（無停電電源機能部）との独立性を高めたシステム構成について研究が重ねられた結果、以下に示す手段により、上記目的が達成されることが見出された。
【００１０】
【課題を解決するための手段】
即ち、本発明によれば、負荷平準化機能と無停電電源機能とを併せ持つ二次電池システムであって、第１の電力系統に接続された高温作動型二次電池と、第１の電力系統と高温作動型二次電池との間に備わり第１の電力系統に対し高温作動型二次電池を充放電させる系統連系用交直変換器と、を有するとともに、第２の電力系統と負荷との間に備わり高温作動型二次電池を電力供給源とした常時インバータ給電方式の無停電電源装置と、高温作動型二次電池と無停電電源装置の直流回路部との間に備わり高温作動型二次電池の電圧を変換する直流チョッパと、を有することを特徴とする高温作動型二次電池システムが提供される。本発明は、第１の電力系統と第２の電力系統とが、分離しているとともに電圧が異なる場合に適用出来ることが好ましい。
【００１１】
又、本発明においては、高温作動型二次電池が系統連系用交直変換器を介し充放電動作を行い第１の電力系統に対する負荷平準化機能を発揮する第１の運転モードと、高温作動型二次電池が無停電電源装置に電力供給し負荷に対する無停電電源機能を発揮する第２の運転モードと、を切り替える運転切替手段を有することが好ましい。このとき、その運転切替手段として、無停電電源装置の直流回路電圧を検出する直流電圧計測器と、直流回路電圧が所定値以下に低下したことを検出する電圧低下判定器と、を有し、電圧低下判定器の判定結果に基づいて、系統連系用交直変換器を停止させるとともに、直流チョッパに二次電圧を一定制御させる手段を用いることが出来る。その直流チョッパは、常時は停止（ゲートブロック）し、電圧低下判定器の判定結果に基づいて瞬時に起動することが好ましい。又、電圧低下判定器の判定結果に基づく系統連系用交直変換器を停止させる信号は光ファイバで伝送されることが好ましい。ノイズの影響なく高速伝送が可能だからであり、瞬低等が発生した時に、系統連系用交直変換器を確実且つ瞬時に停止させることが出来るからである。
【００１２】
更に、本発明においては、無停電電源機能として必要な高温作動型二次電池の停電補償容量を設定可能であるとともに、負荷平準化機能を発揮しているときに、高温作動型二次電池の電池残存容量が停電補償容量に達したら、高温作動型二次電池の負荷平準化運転を停止させる電池残存容量管理手段を有することが好ましい。停電補償を確実に行うことが出来るからである。即ち、電池残存容量管理手段は、負荷平準化機能を発揮しているときは常に高温作動型二次電池が停電補償容量分の蓄えを有しておくようにする手段であり、電池残存容量が停電補償容量に達したらとは停電補償容量にまで減ったらの意味であり、高温作動型二次電池を停止させるとは通常少なくとも放電を止めることを意味する。上記電池残存容量は、高温作動型二次電池の充放電動作に基づく電気容量積算値（Ａｈ）乃至電池電圧から推定した電池深度に基づく残存容量換算値により求めることが出来る。
【００１３】
本発明の高温作動型二次電池システムでは、各構成要素が多重並列化されてなることが好ましい。例えば、系統連系用交直変換器を除く構成要素を多重並列化すると、単一要素が故障しても無停電電源機能を維持出来る。本発明においては、全ての構成要素を比較的容易に多重並列化出来、求められる信頼性のグレードに応じてシステム設計することが可能であり、多方面に適用され得る。又、本発明においては、主構成要素である高温作動型二次電池はナトリウム−硫黄電池であることが好ましい。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態について説明するが、本発明はこれらに限定されて解釈されるべきものではなく、本発明の範囲を逸脱しない限りにおいて、当業者の知識に基づいて、種々の変更、修正、改良を加え得るものである。
【００１５】
本発明は、負荷平準化機能と無停電電源機能とを併せ持つ高温作動型二次電池システムである。高温作動型二次電池システムとは、高温作動型二次電池を電力貯蔵供給源とする二次電池システムをいう。負荷平準化機能とは、日間変動の大きい実負荷のボトムアップとピークカットにより電力供給側からみた負荷の変動を抑制する機能をいい、より具体的には例えば二次電池が低負荷時に電力系統から充電し高負荷時に電力系統へ放電することで実現される機能である。無停電電源機能とは、電力系統に瞬低や停電が生じた場合に負荷に対して無瞬断で電力を補償・供給する機能をいう。
【００１６】
本発明の高温作動型二次電池システムは、第１の電力系統に接続された高温作動型二次電池と、第１の電力系統と高温作動型二次電池との間に備わり第１の電力系統に対し高温作動型二次電池を充放電させる系統連系用交直変換器とを有し、且つ、第２の電力系統と負荷との間に備わり高温作動型二次電池を電力供給源とした常時インバータ給電方式の無停電電源装置と、高温作動型二次電池と無停電電源装置の直流回路部との間に備わり高温作動型二次電池の電圧を変換する直流チョッパと、を有するところに特徴がある。
【００１７】
高温作動型二次電池と系統連系用交直変換器とにより負荷平準化機能部を構成し、高温作動型二次電池を共有しつつ無停電電源装置と直流チョッパとによって無停電電源機能部を構成しているので、連系保護リレー動作時には、負荷平準化機能部（系統連系用交直変換器側）のみを解列させることにより、上記無停電電源機能部（無停電電源装置側）は独立して常時インバータ給電を継続させることが可能となる。尚、直流チョッパを双方向として電池充電も出来るようにしておけば、系統連系用交直変換器側のいかなる機器故障に際しても、完全な無停電電源装置としての機能を確保出来る。
【００１８】
尚、本明細書においては、電力系統とは主に商用電源の系統をいい、無停電電源装置というときには二次電池を除き一般にＣＶＣＦ（定電圧定周波装置）とよばれる構成部分を指す。又、交流から直流へ変換する機器を交直変換器（コンバータ）、直流から交流へ変換する機器を直交変換器（インバータ）とよぶ。無停電電源装置の直流回路部とは、無停電電源装置内の交直変換器と直交変換器との間の電流が直流である回路部分をいい、無停電電源装置の直流回路電圧とは該部分の電圧をいう。
【００１９】
本発明においては、高温作動型二次電池の具体的な電池種別は限定されるものではない。例えば、ナトリウム−硫黄電池、ナトリウム−塩化金属電池等を採用することが出来る。望ましい高温作動型二次電池はナトリウム−硫黄電池である。ナトリウム−硫黄電池は、エネルギー密度が高くフル放電サイクル耐久性が高いので、負荷平準化機能と無停電電源機能とを併せ持つ二次電池システムの二次電池として好適である。
【００２０】
本発明は、上記第１の電力系統と第２の電力系統とが同系統・同電圧の場合にも、異なる場合にも適用可能である。通常、系統連系用システムは約５００ｋＷ以上と比較的大容量となるため、第１の電力系統の電圧（系統連系電圧）として６．６ｋＶとする場合が多い。一方、無停電電源装置は、標準的に内蔵されるバイパス回路の関係もあり、２００Ｖ又は４００Ｖで接続する場合が多く、更に、第１の電力系統と第２の電力系統とが同系統でない場合がある。
【００２１】
本発明の高温作動型二次電池システムは、上記第１の電力系統と第２の電力系統とが分離しているとともに電圧が異なる場合にも適用出来るので、系統連系用交直変換器と常時インバータ給電方式の無停電電源装置とを完全に分離し、無停電電源装置として十分な実績を有する既存製品を概ねそのままの形で活用出来、信頼性の高いシステム構築が可能となる。尚、電力系統とが分離しているとは、電圧の異同を問わず、一の電力系統が他の電力系統と分離して運用出来る構成となっている場合をいう。
【００２２】
本発明の高温作動型二次電池システムの好ましい態様では、高温作動型二次電池が系統連系用交直変換器を介し充放電動作を行い第１の電力系統に対する負荷平準化機能を発揮する第１の運転モードと、高温作動型二次電池が無停電電源装置に電力供給し負荷に対する無停電電源機能を発揮する第２の運転モードと、を切り替える運転切替手段を有するが、この運転切替手段の制御は、無停電電源機能を優先させるように行われることが望ましい。負荷平準化より無停電電源としての機能の方が重要であるからである。
【００２３】
上記運転切替手段は、少なくとも無停電電源装置の直流回路電圧を検出する直流電圧計測器と直流回路電圧が予め規定した所定値以下に低下したことを検出する電圧低下判定器とから構成し、電圧低下判定器の判定結果に基づいて、系統連系用交直変換器に負荷平準化運転停止指令を出し、速やかに直流チョッパを二次電圧一定制御運転させることで実現される。
【００２４】
又、系統連系用交直変換器と直流チョッパの動作干渉を防ぐため、及び、二次電池から無停電電源装置側への不要な微小放電を避けるため、直流チョッパを常時は停止（ゲートブロック）状態としておき、電圧低下判定器の判定結果に基づき、瞬時に起動させることが望ましい。例えば、起動時間を５ｍｓｅｃ以内とすれば、その間は、無停電電源装置の直流回路に標準的に設置される直流コンデンサで十分バックアップ出来るため、負荷側には瞬時も電圧低下を生じることがない。
【００２５】
以下、図面を参照して、具体的な実施形態について説明する。先ず、本発明に係る負荷平準化機能及び無停電電源機能を併せ持つ高温作動型二次電池システムの基本構成を、その実施態様の一例である図１に基づいて説明する。図１に示される高温作動型二次電池システム１０は、ナトリウム−硫黄電池である高温作動型二次電池３を共有しつつ、例えば６．６ｋＶの電力系統１に接続された系統連系システムである負荷平準化機能部１７と、上記電力系統１に対する系統連系システムを構成しない無停電電源機能部１８とからなる。
【００２６】
負荷平準化機能部１７は、高温作動型二次電池３の他に、電力系統１との間に変圧器９及び系統連系用交直変換器４及び連系遮断器１０１を有する。
【００２７】
負荷平準化機能部１７は、定常時は第１の運転モードで運転され、例えば電力消費量の多い昼間には、高温作動型二次電池３からの直流の出力を系統連系用交直変換器４により交流に変換し変圧器９で昇圧して電力系統１に供給する。又、例えば電力消費量の少ない夜間に、電力系統１からの交流電力を変圧器９で降圧し系統連系用交直変換器４により直流に変換して高温作動型二次電池３へ入力し充電する。このような運転により、負荷平準化機能部１７は、電力系統１に接続された図示しない負荷の変動を吸収し平準化を図る。
【００２８】
本発明に係る高温作動型二次電池システム１０においては、負荷平準化機能部１７が第１の運転モードで運転する間は、電池残存容量管理手段によって、高温作動型二次電池３の電池残存容量が予め設定された停電補償容量に達したときを高温作動型二次電池３の放電終点としている。停電補償容量とは無停電電源機能として必要な高温作動型二次電池の容量である。第１の運転モードで運転しているときに、常に停電補償容量を保持しておくことにより、後述する第２の運転モードに切り替わったときに、停電補償を確実なものにすることが出来る。
【００２９】
電池残存容量管理手段は、例えば、図示しない制御装置に、停電補償容量を書き換え可能に記憶しておき、高温作動型二次電池３の電池残存容量と常時比較することで実現される。その電池残存容量は、例えば、図示しない制御装置において、高温作動型二次電池３の充電動作及び放電動作にかかる電気容量（Ａｈ）を積算するか又は電池電圧から推定した深度から換算するか、の何れか若しくは両方を用いて、求めることが出来る。
【００３０】
無停電電源機能部１８は、高温作動型二次電池３の他に、無停電電源装置１１と、それらの間に設けられる直流チョッパ５とを有する。無停電電源装置１１は、例えば２１０Ｖの電力系統７とそれに接続された負荷２との間に備わる。無停電電源装置１１は、交直変換器１４と直交変換器５１を主構成要素とし、高速切替スイッチ４１と変圧器１９、及び、電力系統６に接続された無瞬断バイパス回路４７と保守バイパス回路４８を有する。尚、高温作動型二次電池３は共有されるため、負荷平準化機能部１７と無停電電源機能部１８の何れかの構成要素になるが、図１では、便宜上、高温作動型二次電池３を負荷平準化機能部１７の構成要素として描いている。
【００３１】
無停電電源機能部１８において、定常時（第１の運転モード時）は、電力系統７から負荷２へ、交直変換器１４及び直交変換器５１を通じ（常時インバータ給電方式で）電力供給が行われる。高温作動型二次電池３は、直流チョッパ５を介し、交直変換器１４と直交変換器５１の間の直流回路部で接続される。一般に、二次電池を電力供給源とした常時インバータ給電方式の無停電電源装置では、無停電電源装置側から二次電池へ直流電力を供給し充電を行うが、本発明に係る高温作動型二次電池システム１０では、定常時には、直流チョッパ５はゲートブロック状態にされており、無停電電源装置１１から高温作動型二次電池３へ直流電力が供給され充電が行なわれることも、又、高温作動型二次電池３から無停電電源装置１１を介して負荷２へ電力供給が行われることもない。
【００３２】
本発明に係る高温作動型二次電池システム１０では、無停電電源装置１１の交直変換器１４と直交変換器５１との間の直流回路部の所定箇所である点Ｐに、直流回路電圧を常時測定する（図示しない）直流電圧計測器が設けられる。そして、その直流電圧計測器が測定した電圧値は、例えば図示しない制御装置へ送られ、制御装置内に設けられた電圧低下判定器によって、直流回路電圧が予め規定した所定値以下に低下したか否か常時判定される。電圧低下判定器により、直流回路電圧が所定値以下に低下したと判定されれば、瞬低乃至停電が生じたと判断され、第２の運転モードに切り替わり、瞬時に制御装置から光ファイバを通じて系統連系用交直変換器４へ負荷平準化運転停止指令信号が送られ、併せて、直流チョッパ５へ二次電圧一定制御運転指令信号が送られる。
【００３３】
系統連系用交直変換器４が負荷平準化運転を停止し、直流チョッパ５が二次電圧一定制御運転を開始すると、高温作動型二次電池３の電気エネルギーは、負荷平準化運転を停止していることにより電池の過負荷状態を生じることなく全て無停電電源装置１１側へ供給されるため、負荷２側において瞬低は現れない。負荷２への電力供給源が、電力系統７による常時インバータ給電から高温作動型二次電池３へ切り替わる動作については概ね５ｍｓｅｃ以内と極短時間であるため、切り替わる間の電気容量は、既存製品の無停電電源装置１１に標準装備される直流コンデンサで十分にバックアップされる。
【００３４】
本発明に係る高温作動型二次電池システム１０では、連系保護リレー４４が動作したときは、一旦、系統連系システムである負荷平準化機能部１７が電力系統１から解列されるが、この場合でも、無停電電源機能部１８は、負荷平準化機能部１７とは独立して継続運転され得る。即ち、系統連系技術要件ガイドラインに準じた適正なシステムであるとともに、負荷２に僅かでも瞬低を生じさせることがなく、無停電電源機能としての信頼性が高いシステムである。尚、直流チョッパを双方向として電池充電も出来るようにしておけば、系統連系用交直変換器側のいかなる機器故障に際しても、完全な無停電電源装置としての機能を確保出来る。
【００３５】
次に、本発明に係る負荷平準化機能及び無停電電源機能を併せ持つ高温作動型二次電池システムの応用例を、図２に基づいて説明する。図２に示される高温作動型二次電池システム２０は、並列冗長無停電電源機能付きＮＡＳ電池システムの例であって、図１に示される高温作動型二次電池システム１０の無停電電源機能に係る主な構成要素を並列に二重化したものである。
【００３６】
高温作動型二次電池システム２０は、ナトリウム−硫黄電池である高温作動型二次電池３を共有しつつ、例えば６．６ｋＶの電力系統１に接続された系統連系システムである負荷平準化機能部２７と、上記電力系統１に対する系統連系システムを構成しない無停電電源機能部２８とからなる点は、高温作動型二次電池システム１０に準じるシステムである。
【００３７】
負荷平準化機能部２７は、電力系統１に変圧器９が接続され、その二次側に、系統連系用交直変換器４と高温作動型二次電池３とが並列に２系列設けられている。負荷平準化機能部２７は負荷平準化機能部１７に準じて運転される。通常、２系列の系統連系用交直変換器４及び高温作動型二次電池３は電力系統１に対し同時に充放電動作を行い、電力系統１に接続された図示しない負荷の日間変動を吸収し平準化を図る。
【００３８】
本発明に係る高温作動型二次電池システム２０においては、負荷平準化機能部２７が第１の運転モードで運転する間において、高温作動型二次電池３の電池残存容量は、各系列毎に停電補償容量が確保されるように管理され、何れの系列が、第２の運転モードに切り替わったときでも、停電補償は確実に行われる。
【００３９】
無停電電源機能部２８は、負荷平準化機能部２７と共有する２系列の高温作動型二次電池３の他に、無停電電源装置２１において交直変換器１４、直交変換器５１及び変圧器１９が並列に二重化されている。又、２系列の高温作動型二次電池３と、無停電電源装置２１の各２系列の交直変換器１４と直交変換器５１の間の直流回路部との間に設けられる直流チョッパ５も、２系列設けられている。
【００４０】
無停電電源機能部２８における、定常時（第１の運転モード時）の運転動作は、無停電電源機能部１８に準じて行われ、通常、電力系統７から負荷２へ、２系列の交直変換器１４及び直交変換器５１を通じ常時同時に電力供給が行われる。又、２系列の直流チョッパ５はともにゲートブロック状態にされており、無停電電源装置２１側から２系列の高温作動型二次電池３へ直流電力が供給され充電が行なわれることも、又、２系列の高温作動型二次電池３から無停電電源装置２１を介して負荷２へ電力供給が行われることもない。
【００４１】
本発明に係る高温作動型二次電池システム２０は、第１の運転モードから第２の運転モードに切り替わる手段については、高温作動型二次電池システム１０に準じる。切替時に、負荷２側において瞬低は現れないのも同様である。更に、連系保護リレー４４が動作し、負荷平準化機能部２７が電力系統１から解列されたときに、無停電電源機能部２８が独立して継続運転され得ることも同様であり、系統連系技術要件ガイドラインに準ずる適正なシステムであるとともに、負荷２に僅かでも瞬低を生じさせることがなく、無停電電源機能としての信頼性が高いシステムである。
【００４２】
加えて、本発明に係る高温作動型二次電池システム２０は、無停電電源機能に係る主な構成要素が二重化されているので、一の構成要素が故障した場合にも、負荷平準化機能及び無停電電源機能を発揮し得るシステムとして維持され得る。従って、負荷２において瞬低乃至停電が生じる可能性は極低く、負荷２が僅かな停止も許されない最重要な生産設備等である場合に、好適である。
【００４３】
【発明の効果】
以上説明したように、本発明の高温作動型二次電池システムは、負荷平準化機能と無停電電源機能とを併せ持ち、系統連系技術要件ガイドラインに従い連系保護リレーが動作したときに電力系統から系統連系システムを解列しても、無停電電源機能部は独立して運転を継続出来、負荷に瞬低乃至停電を生じさせることがない。従って、本発明の高温作動型二次電池システムは、コンピュータシステムや通信ネットワークにより制御・稼動される重要な生産設備等への電源供給システムとして好適に用いられ得る。
【図面の簡単な説明】
【図１】本発明の高温作動型二次電池システムの一実施形態を示す構成図である。
【図２】本発明の高温作動型二次電池システムの他の実施形態を示す構成図である。
【図３】従来の二次電池システムの一例を示す構成図である。
【符号の説明】
１，６，７…電力系統、２…負荷、３…高温作動型二次電池、４…系統連系用交直変換器、５…直流チョッパ、９…変圧器、１０，２０…高温作動型二次電池システム、１１，２１，３１…無停電電源装置、１３…二次電池、１４…交直変換器、１７，２７…負荷平準化機能部、１８，２８…無停電電源機能部、１９…変圧器、３０…二次電池システム、４１…高速切替スイッチ、４３…交直変換器、４４…連系保護リレー、４７…無瞬断バイパス回路、４８…保守バイパス回路、５１…直交変換器、１０１…連系遮断器。[0001]
BACKGROUND OF THE INVENTION
The present invention has both a load leveling function and an uninterruptible power supply function, and normally exhibits a load leveling function. In addition, when a power failure occurs, the uninterruptible power supply function is demonstrated to supply power to the load in order to compensate for instantaneous drop or power failure The present invention relates to a high temperature operation type secondary battery system.
[0002]
[Prior art]
In many cases, factories operate during the day and shut down at night or reduce operating rates. Also, the time when people work in the office is usually daytime. Therefore, the difference in power load between day and night increases. Furthermore, since the demand for cooling and heating increases due to extreme heat or severe cold in summer and winter compared to spring and autumn when it is easy to spend without air conditioning, the power load can vary depending on the season. In recent years, these disparities have been increasing, and the load factor representing the operating rate of the power supply facilities has been decreasing year by year. On the other hand, there is an increasing demand for reducing power costs for the purpose of improving industrial competitiveness, and load leveling for power supply is considered a very important issue. As one of the countermeasures, the development of a high-efficiency and large-capacity secondary battery has been promoted, and it has been put into practical use as a battery power storage system that can charge and discharge according to the load state and suppress load fluctuations as seen from the power supply equipment. Yes.
[0003]
In modern society, highly developed computer systems and online systems using communication networks are widely used, and important production facilities are controlled and operated by these computer systems and communication networks. Therefore, if an instantaneous drop (voltage drop) or a power failure occurs in the supplied power, it may cause a great loss to various services and products, and the stability of the quality of the power supply system is a very important issue. As a countermeasure against this, the installation of an uninterruptible power supply is effective, and an uninterruptible power supply using a secondary battery as a power supply source is well known.
[0004]
As described above, the secondary battery is useful for realizing load leveling and stabilizing the quality of supplied power. Therefore, conventionally, a system having both a load leveling function and an uninterruptible power supply function using the same secondary battery as a power storage supply source has been proposed. For example, NTT Facilities Co., Ltd. (NTTF3080A0109) [Electric Power Storage System], Nippon Yasuko Co., Ltd. (issued in September 2002) “NAS Battery Power Storage System”, Tokyo Electric Power Company's Leaflet “UPS Combined (200kW Class) According to “) NAS battery”, a system configuration having both a load leveling function and an uninterruptible power supply function in a continuous inverter type uninterruptible power supply is specified. A secondary battery system whose configuration is shown in FIG. 3 is known.
[0005]
The secondary battery system 30 includes, as a main component, an uninterruptible power supply 31 of a constant inverter power supply system that mainly uses the secondary battery 13 as a power supply source. The uninterruptible power supply 31 includes an AC / DC converter 43 corresponding to a DC power supply and an orthogonal converter 51 (inverter) as essential components, and the high-speed changeover switch 41, the transformer 9, and the power system 6 This is an apparatus having a non-instantaneous disconnection bypass circuit 47 and a maintenance bypass circuit 48 connected to each other.
[0006]
In the secondary battery system 30, the AC power supplied from the high-voltage (eg, 6.6 kV) power system 1 is normally stepped down to a low voltage (eg, 210 V) by the transformer 9 and converted to DC power by the AC / DC converter 43. It is converted, supplied to the orthogonal converter 51 while charging the secondary battery 13, converted again to AC power by the orthogonal converter 51, and supplied to the load 2. Alternatively, when the secondary battery 13 is in the discharge mode, part or all of the battery output is supplied to the load 2.
[0007]
Then, when the power system 1 loses power, the DC power is discharged from the secondary battery 13 and supplied to the orthogonal transformer 51, so that the AC power is supplied from the orthogonal converter 51 to the load 2 without instantaneous interruption. In this way, the secondary battery system 30 realizes an uninterruptible power supply function. In addition, the secondary battery system 30 allows the AC / DC converter 43 to perform bidirectional conversion, so that electric power can be supplied to the load leveling system, and the load leveling function can be greatly utilized.
[0008]
However, in the secondary battery system 30, when the interconnection protection relay 44 is operated for some reason based on the grid interconnection technical requirement guidelines (former revision of the Ministry of International Trade and Industry / Resource and Energy Agency 1998), It is necessary to open the interconnection breaker 101 as a secondary battery system, which is a power system, and disconnect from the power system 1. When the interconnection breaker 101 is disconnected, the secondary battery 13 starts discharging, and after the interconnection protection relay 44 is restored, it is automatically restarted to return to the original state. There is no instantaneous drop in the load 2. However, since the grid protection relay 44 must be disconnected from the power system when the grid protection relay 44 operates, the system cannot be restarted in the event that the grid protection relay 44 breaks down. Reliability as a power supply function may be impaired. This can be a serious problem when the load 2 is a particularly important facility.
[0009]
[Problems to be solved by the invention]
This invention makes it a subject to provide the secondary battery system which cannot produce an above-described problem. More specifically, the object of the present invention is to have both a load leveling function and an uninterruptible power supply function, and from the power grid to the grid interconnection system when the grid protection relay operates according to the grid interconnection technical requirement guidelines. And providing a more reliable secondary battery system that does not lose the uninterruptible power supply function even if the interconnection protection relay breaks down. The structure of the conventional secondary battery system has been reviewed and studied, and while sharing the secondary battery, the part that develops the load leveling function (load leveling function part) and the part that develops the uninterruptible power supply function (uninterruptible power supply) As a result of repeated studies on the system configuration with increased independence from the functional unit), it has been found that the above object can be achieved by the following means.
[0010]
[Means for Solving the Problems]
In other words, according to the present invention, there is provided a secondary battery system having both a load leveling function and an uninterruptible power supply function, the high temperature operation type secondary battery connected to the first power system, and the first power system. A grid connection AC / DC converter between the first power system and the high-temperature operation type secondary battery, and charging and discharging the high-temperature operation type secondary battery with respect to the first power system. A normal inverter power supply type uninterruptible power supply using a high temperature operation type secondary battery as a power supply source, and a high temperature operation type provided between a high temperature operation type secondary battery and the DC circuit part of the uninterruptible power supply unit There is provided a high temperature operation type secondary battery system comprising a DC chopper for converting the voltage of the secondary battery. The present invention is preferably applicable when the first power system and the second power system are separated and have different voltages.
[0011]
Further, in the present invention, the first operation mode in which the high temperature operation type secondary battery performs the charge / discharge operation through the grid connection AC / DC converter and exhibits the load leveling function for the first power system, and the high temperature operation It is preferable to have an operation switching means for switching between a second operation mode in which the type secondary battery supplies power to the uninterruptible power supply and exhibits an uninterruptible power supply function for a load. At this time, as the operation switching means, it has a DC voltage measuring device that detects the DC circuit voltage of the uninterruptible power supply, and a voltage drop determination device that detects that the DC circuit voltage has dropped below a predetermined value, Based on the determination result of the voltage drop determiner, it is possible to use means for stopping the system interconnection AC / DC converter and causing the DC chopper to control the secondary voltage constant. The DC chopper is preferably stopped (gate block) at all times and is activated instantly based on the determination result of the voltage drop determination device. Moreover, it is preferable that the signal for stopping the grid connection AC / DC converter based on the determination result of the voltage drop determination device is transmitted through an optical fiber. This is because high-speed transmission is possible without the influence of noise, and when a voltage sag or the like occurs, the grid connection AC / DC converter can be reliably and instantaneously stopped.
[0012]
Furthermore, in the present invention, the power failure compensation capacity of the high temperature operation type secondary battery required as an uninterruptible power supply function can be set, and when the load leveling function is exhibited, the high temperature operation type secondary battery When the battery remaining capacity reaches the power failure compensation capacity, it is preferable to have battery remaining capacity management means for stopping the load leveling operation of the high temperature operation type secondary battery. This is because power failure compensation can be performed reliably. In other words, the battery remaining capacity management means is a means for ensuring that the high temperature operation type secondary battery has a storage for the power failure compensation capacity whenever the load leveling function is exhibited. When the power failure compensation capacity is reached, it means that the capacity has been reduced to the power failure compensation capacity. Stopping the high temperature operation type secondary battery usually means at least stopping the discharge. The battery remaining capacity can be obtained from an accumulated electric capacity value (Ah) based on the charge / discharge operation of the high temperature operation type secondary battery or a remaining capacity converted value based on the battery depth estimated from the battery voltage.
[0013]
In the high-temperature operation type secondary battery system of the present invention, it is preferable that each component is multi-parallelized. For example, when components other than the grid interconnection AC / DC converter are parallelized, the uninterruptible power supply function can be maintained even if a single element fails. In the present invention, it is possible to relatively easily multiplex-parallelize all the constituent elements, and to design a system in accordance with a required reliability grade, which can be applied in various fields. In the present invention, the high-temperature operation type secondary battery as the main component is preferably a sodium-sulfur battery.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described. However, the present invention should not be construed as being limited thereto, and various modifications can be made based on the knowledge of those skilled in the art without departing from the scope of the present invention. , Can be modified and improved.
[0015]
The present invention is a high temperature operation type secondary battery system having both a load leveling function and an uninterruptible power supply function. The high temperature operation type secondary battery system refers to a secondary battery system using a high temperature operation type secondary battery as a power storage supply source. The load leveling function is a function that suppresses fluctuations in the load seen from the power supply side by bottom-up and peak-cutting of the actual load, which has a large daily fluctuation, and more specifically, for example, when the secondary battery has a low load, the power system This function is realized by charging from the power source and discharging to the power system at high load. The uninterruptible power supply function refers to a function that compensates and supplies electric power to a load without interruption in the event of a momentary voltage drop or power outage.
[0016]
A high temperature operation type secondary battery system according to the present invention includes a high temperature operation type secondary battery connected to a first electric power system, and a first electric power provided between the first electric power system and the high temperature operation type secondary battery. A grid connection AC / DC converter for charging / discharging the high temperature operation type secondary battery to the system, and the high temperature operation type secondary battery is provided between the second power system and the load as a power supply source. A continuous inverter power supply type uninterruptible power supply, and a DC chopper provided between the high temperature operation type secondary battery and the DC circuit part of the uninterruptible power supply unit for converting the voltage of the high temperature operation type secondary battery. There is a feature.
[0017]
The load leveling function unit is composed of the high-temperature operation type secondary battery and the AC / DC converter for grid connection, and the uninterruptible power supply unit and the DC chopper are used to share the high-temperature operation type secondary battery. Because it is configured, the above uninterruptible power supply function unit (uninterruptible power supply side) can be obtained by disconnecting only the load leveling function unit (system interconnection AC / DC converter side) when the interconnection protection relay is operating. It becomes possible to continue the inverter power supply continuously independently. In addition, if the battery can be charged with the DC chopper being bidirectional, it is possible to ensure a complete function as an uninterruptible power supply in the event of any equipment failure on the system interconnection AC / DC converter side.
[0018]
In this specification, the power system mainly refers to a commercial power system, and when it is referred to as an uninterruptible power supply, it refers to a component generally called a CVCF (constant voltage constant frequency apparatus) except for a secondary battery. A device that converts AC to DC is called an AC / DC converter (converter), and a device that converts DC to AC is called an orthogonal converter (inverter). The DC circuit part of the uninterruptible power supply means a circuit part in which the current between the AC / DC converter and the orthogonal converter in the uninterruptible power supply is DC, and the DC circuit voltage of the uninterruptible power supply is the part Voltage.
[0019]
In the present invention, the specific battery type of the high temperature operation type secondary battery is not limited. For example, a sodium-sulfur battery, a sodium-metal chloride battery, or the like can be employed. A desirable high temperature operation type secondary battery is a sodium-sulfur battery. Since the sodium-sulfur battery has a high energy density and high full discharge cycle durability, it is suitable as a secondary battery of a secondary battery system having both a load leveling function and an uninterruptible power supply function.
[0020]
The present invention can be applied to cases where the first power system and the second power system are the same system and the same voltage or different. Usually, the grid connection system has a relatively large capacity of about 500 kW or more, and therefore the voltage of the first power grid (system grid voltage) is often set to 6.6 kV. On the other hand, the uninterruptible power supply also has a built-in bypass circuit relationship and is often connected at 200V or 400V. Furthermore, the first power system and the second power system are not the same system. There is.
[0021]
The high temperature operation type secondary battery system of the present invention can be applied to the case where the first power system and the second power system are separated and have different voltages. The inverter-powered uninterruptible power supply can be completely separated, and existing products with a sufficient track record as an uninterruptible power supply can be used almost as they are, and a highly reliable system can be constructed. The term “separated from the power system” refers to a case where one power system can be operated separately from other power systems regardless of the difference in voltage.
[0022]
In a preferred aspect of the high temperature operation type secondary battery system of the present invention, the high temperature operation type secondary battery performs charge / discharge operation via the grid connection AC / DC converter and exhibits a load leveling function for the first power system. The operation switching means for switching between the first operation mode and the second operation mode in which the high-temperature operation type secondary battery supplies power to the uninterruptible power supply and exhibits the uninterruptible power supply function for the load. It is desirable that the control is performed so as to give priority to the uninterruptible power supply function. This is because the function as an uninterruptible power supply is more important than load leveling.
[0023]
The operation switching means comprises at least a DC voltage measuring device for detecting the DC circuit voltage of the uninterruptible power supply and a voltage drop determining device for detecting that the DC circuit voltage has fallen below a predetermined value. This is realized by issuing a load leveling operation stop command to the grid connection AC / DC converter based on the determination result of the lowering determination unit, and promptly causing the DC chopper to perform a secondary voltage constant control operation.
[0024]
Also, the DC chopper is always stopped (gate block) in order to prevent operation interference between the AC / DC converter for grid connection and the DC chopper, and to avoid unnecessary minute discharge from the secondary battery to the uninterruptible power supply. It is desirable to set it in a state and instantly start it based on the determination result of the voltage drop determiner. For example, if the start-up time is set to 5 msec or less, the DC side of the uninterruptible power supply can be backed up with a DC capacitor that is standardly installed, so that no voltage drop occurs instantaneously on the load side.
[0025]
Hereinafter, specific embodiments will be described with reference to the drawings. First, a basic configuration of a high temperature operation type secondary battery system having both a load leveling function and an uninterruptible power supply function according to the present invention will be described with reference to FIG. 1 which is an example of the embodiment. A high temperature operation type secondary battery system 10 shown in FIG. 1 is a grid interconnection system connected to a power system 1 of 6.6 kV, for example, while sharing a high temperature operation type secondary battery 3 which is a sodium-sulfur battery. It comprises a certain load leveling function unit 17 and an uninterruptible power supply function unit 18 that does not constitute a grid interconnection system for the power system 1.
[0026]
The load leveling function unit 17 includes, in addition to the high temperature operation type secondary battery 3, a transformer 9, a grid interconnection AC / DC converter 4, and a grid breaker 101 between the power grid 1.
[0027]
The load leveling function unit 17 is operated in the first operation mode during normal operation. For example, during the daytime when the power consumption is large, the DC output from the high-temperature operation type secondary battery 3 is converted into an AC / DC converter for grid connection. 4 is converted into alternating current, boosted by a transformer 9 and supplied to the power system 1. Also, for example, at night when power consumption is low, AC power from the power system 1 is stepped down by the transformer 9, converted into direct current by the AC / DC converter 4 for system interconnection, and input to the high temperature operation type secondary battery 3 for charging. To do. By such an operation, the load leveling function unit 17 absorbs fluctuations of a load (not shown) connected to the power system 1 and achieves leveling.
[0028]
In the high temperature operation type secondary battery system 10 according to the present invention, while the load leveling function unit 17 operates in the first operation mode, the remaining battery capacity of the high temperature operation type secondary battery 3 is maintained by the battery remaining capacity management means. The time when the capacity reaches a preset power failure compensation capacity is defined as the discharge end point of the high temperature operation type secondary battery 3. The power outage compensation capacity is the capacity of the high temperature operation type secondary battery required as an uninterruptible power supply function. By maintaining the power failure compensation capacity at all times when operating in the first operation mode, power failure compensation can be ensured when switching to the second operation mode described later.
[0029]
The battery remaining capacity management means is realized, for example, by storing the power failure compensation capacity in a control device (not shown) in a rewritable manner and constantly comparing it with the battery remaining capacity of the high temperature operation type secondary battery 3. For example, in a control device (not shown), the remaining battery capacity is obtained by integrating the electric capacity (Ah) applied to the charging operation and discharging operation of the high temperature operation type secondary battery 3 or converting from the depth estimated from the battery voltage, Either or both of these can be used.
[0030]
The uninterruptible power supply function unit 18 includes an uninterruptible power supply 11 and a DC chopper 5 provided between them, in addition to the high temperature operation type secondary battery 3. The uninterruptible power supply 11 is provided, for example, between the 210V power system 7 and the load 2 connected thereto. The uninterruptible power supply 11 has an AC / DC converter 14 and an orthogonal converter 51 as main components, an uninterruptible bypass circuit 47 and a maintenance bypass circuit connected to the high-speed changeover switch 41, the transformer 19, and the power system 6. 48. In addition, since the high temperature operation type secondary battery 3 is shared, it becomes one of the components of the load leveling function unit 17 and the uninterruptible power supply function unit 18, but in FIG. 3 is depicted as a component of the load leveling function unit 17.
[0031]
In the uninterruptible power supply function unit 18, during normal operation (in the first operation mode), power is supplied from the power system 7 to the load 2 through the AC / DC converter 14 and the orthogonal converter 51 (always using an inverter feeding method). . The high temperature operation type secondary battery 3 is connected to the DC circuit unit between the AC / DC converter 14 and the orthogonal converter 51 through the DC chopper 5. In general, in an uninterruptible power supply device of a continuous inverter power supply system using a secondary battery as a power supply source, DC power is supplied to the secondary battery from the uninterruptible power supply side for charging. In the secondary battery system 10, the DC chopper 5 is in a gate block state in a steady state, and the DC power is supplied from the uninterruptible power supply 11 to the high temperature operation type secondary battery 3 to be charged. Power is not supplied from the actuated secondary battery 3 to the load 2 via the uninterruptible power supply 11.
[0032]
In the high temperature operation type secondary battery system 10 according to the present invention, the DC circuit voltage is always applied to the point P which is a predetermined location of the DC circuit section between the AC / DC converter 14 and the orthogonal converter 51 of the uninterruptible power supply 11. A DC voltage measuring device (not shown) for measurement is provided. Then, the voltage value measured by the DC voltage measuring device is sent to, for example, a control device (not shown), and the voltage drop determination device provided in the control device has reduced the DC circuit voltage to a predetermined value or less. It is always determined whether or not. If it is determined by the voltage drop determiner that the DC circuit voltage has dropped below a predetermined value, it is determined that an instantaneous drop or power failure has occurred, and the operation mode is switched to the second operation mode. A load leveling operation stop command signal is sent to the system AC / DC converter 4 and, at the same time, a secondary voltage constant control operation command signal is sent to the DC chopper 5.
[0033]
When the grid connection AC / DC converter 4 stops the load leveling operation and the DC chopper 5 starts the secondary voltage constant control operation, the electric energy of the high temperature operation type secondary battery 3 stops the load leveling operation. As a result, all the power is supplied to the uninterruptible power supply 11 side without causing an overload state of the battery, so that no instantaneous drop appears on the load 2 side. The operation of switching the power supply source to the load 2 from the constant inverter power supply by the power system 7 to the high temperature operation type secondary battery 3 is within an extremely short time of approximately 5 msec. The uninterruptible power supply 11 is fully backed up by a DC capacitor provided as standard.
[0034]
In the high temperature operation type secondary battery system 10 according to the present invention, when the interconnection protection relay 44 is operated, the load leveling function unit 17 that is a grid interconnection system is once disconnected from the power system 1. Even in this case, the uninterruptible power supply function unit 18 can be continuously operated independently of the load leveling function unit 17. That is, the system is an appropriate system conforming to the grid interconnection technical requirement guideline, and does not cause a slight drop in the load 2, and has high reliability as an uninterruptible power supply function. In addition, if the battery can be charged with the DC chopper being bidirectional, it is possible to ensure a complete function as an uninterruptible power supply in the event of any equipment failure on the system interconnection AC / DC converter side.
[0035]
Next, an application example of the high temperature operation type secondary battery system having both the load leveling function and the uninterruptible power supply function according to the present invention will be described with reference to FIG. A high temperature operation type secondary battery system 20 shown in FIG. 2 is an example of a NAS battery system with a parallel redundant uninterruptible power supply function, and is an uninterruptible power supply function of the high temperature operation type secondary battery system 10 shown in FIG. Such main components are duplicated in parallel.
[0036]
The high temperature operation type secondary battery system 20 shares a high temperature operation type secondary battery 3 that is a sodium-sulfur battery, and is a load leveling function that is a grid interconnection system connected to the power system 1 of 6.6 kV, for example. The point which consists of the part 27 and the uninterruptible power supply function part 28 which does not comprise the grid connection system with respect to the said electric power grid | system 1 is a system according to the high temperature operation type secondary battery system 10. FIG.
[0037]
In the load leveling function unit 27, the transformer 9 is connected to the power system 1, and on the secondary side, the grid connection AC / DC converter 4 and the high-temperature operation type secondary battery 3 are provided in two series in parallel. Yes. The load leveling function unit 27 is operated according to the load leveling function unit 17. Normally, the two-system grid-connected AC / DC converter 4 and the high-temperature operation type secondary battery 3 perform charging / discharging operations on the power system 1 at the same time, and absorb daily fluctuations of a load (not shown) connected to the power system 1. To achieve leveling.
[0038]
In the high temperature operation type secondary battery system 20 according to the present invention, while the load leveling function unit 27 operates in the first operation mode, the battery remaining capacity of the high temperature operation type secondary battery 3 is different for each series. The power failure compensation capacity is managed to be ensured, and the power failure compensation is surely performed even when any of the series is switched to the second operation mode.
[0039]
The uninterruptible power supply function unit 28 includes the AC / DC converter 14, the orthogonal converter 51, and the transformer 19 in the uninterruptible power supply 21 in addition to the two series of high temperature operation type secondary batteries 3 shared with the load leveling function unit 27. Are duplicated in parallel. A DC chopper 5 provided between the two series of high temperature operation type secondary batteries 3 and the DC circuit part between the two series AC / DC converters 14 and the orthogonal converters 51 of the uninterruptible power supply 21 is also provided. Two series are provided.
[0040]
The operation of the uninterruptible power supply function unit 28 during normal operation (in the first operation mode) is performed in accordance with the uninterruptible power supply function unit 18 and is normally converted from power system 7 to load 2 in two series of AC / DC conversion. The power supply is always performed simultaneously through the converter 14 and the orthogonal transformer 51. The two series DC choppers 5 are both in a gate block state, and DC power is supplied from the uninterruptible power supply 21 side to the two series high temperature operation type secondary batteries 3 for charging. Power is not supplied from the two series of high temperature operation type secondary batteries 3 to the load 2 via the uninterruptible power supply 21.
[0041]
The high temperature operation type secondary battery system 20 according to the present invention conforms to the high temperature operation type secondary battery system 10 with respect to the means for switching from the first operation mode to the second operation mode. Similarly, no instantaneous drop appears on the load 2 side at the time of switching. Further, when the interconnection protection relay 44 operates and the load leveling function unit 27 is disconnected from the power system 1, the uninterruptible power supply function unit 28 can be continuously operated independently. It is an appropriate system that conforms to the guidelines for interconnection technical requirements, and does not cause even a slight drop in the load 2, and is a highly reliable system as an uninterruptible power supply function.
[0042]
In addition, in the high temperature operation type secondary battery system 20 according to the present invention, main components related to the uninterruptible power supply function are duplicated, so that even when one component fails, the load leveling function and It can be maintained as a system capable of performing an uninterruptible power supply function. Therefore, the possibility that an instantaneous voltage drop or a power failure occurs in the load 2 is extremely low, which is suitable when the load 2 is the most important production facility that does not allow a slight stop.
[0043]
【The invention's effect】
As described above, the high-temperature operation type secondary battery system of the present invention has both a load leveling function and an uninterruptible power supply function, and when the interconnection protection relay operates according to the grid interconnection technical requirement guidelines, Even if the grid interconnection system is disconnected, the uninterruptible power supply function unit can continue to operate independently, and the load does not cause an instantaneous drop or a power failure. Therefore, the high-temperature operation type secondary battery system of the present invention can be suitably used as a power supply system for important production facilities controlled and operated by a computer system or a communication network.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a high temperature operation type secondary battery system of the present invention.
FIG. 2 is a configuration diagram showing another embodiment of the high temperature operation type secondary battery system of the present invention.
FIG. 3 is a configuration diagram illustrating an example of a conventional secondary battery system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 6, 7 ... Electric power system, 2 ... Load, 3 ... High temperature operation type secondary battery, 4 ... Grid connection AC / DC converter, 5 ... DC chopper, 9 ... Transformer, 10, 20 ... High temperature operation type 2 Secondary battery system, 11, 21, 31 ... uninterruptible power supply, 13 ... secondary battery, 14 ... AC / DC converter, 17, 27 ... load leveling function unit, 18, 28 ... uninterruptible power supply function unit, 19 ... transformer 30 ... secondary battery system, 41 ... high-speed switch, 43 ... AC / DC converter, 44 ... interconnection protection relay, 47 ... uninterruptible bypass circuit, 48 ... maintenance bypass circuit, 51 ... orthogonal converter, 101 ... Interconnection breaker.

Claims

A secondary battery system having both a load leveling function and an uninterruptible power supply function,
A high temperature operation type secondary battery connected to a first power system, and the high temperature operation type secondary battery provided between the first power system and the high temperature operation type secondary battery. A grid interconnection AC / DC converter for charging / discharging the battery,
An uninterruptible power supply of an always-inverted power supply system provided between the second power system and a load and using the high temperature operation type secondary battery as a power supply source, and the high temperature operation type secondary battery and the uninterruptible power supply unit. A high-temperature operation type secondary battery system, comprising: a direct-current chopper provided between the DC circuit unit and converting the voltage of the high-temperature operation type secondary battery.

The high temperature operation type secondary battery system according to claim 1, wherein the first power system and the second power system are separated and have different voltages.

A first operation mode in which the high temperature operation type secondary battery performs charge / discharge operation via the grid connection AC / DC converter and exhibits a load leveling function for the first power system; and the high temperature operation type secondary battery 2. The high-temperature operation type secondary battery system according to claim 1, further comprising an operation switching unit that switches between a second operation mode in which a battery supplies power to the uninterruptible power supply and exhibits an uninterruptible power supply function for the load.

The operation switching means includes a DC voltage measuring device that detects a DC circuit voltage of the uninterruptible power supply, and a voltage drop determination device that detects that the DC circuit voltage has dropped below a predetermined value, 4. The high-temperature operation type second apparatus according to claim 3, which is a means that can stop the grid connection AC / DC converter based on the determination result of the voltage drop determination unit and can cause the DC chopper to constantly control the secondary voltage. Next battery system.

5. The high-temperature operation type secondary battery system according to claim 4, wherein the DC chopper is normally stopped (gate block) and can be instantly started based on a determination result of the voltage drop determination unit.

The high temperature operation type secondary battery system according to claim 4, wherein a signal for stopping the grid interconnection AC / DC converter based on a determination result of the voltage drop determination unit is transmitted by an optical fiber.

The power failure compensation capacity of the high temperature operation type secondary battery required as an uninterruptible power supply function can be set and the remaining capacity of the battery of the high temperature operation type secondary battery is The high temperature operation type secondary battery system according to claim 1, further comprising a battery remaining capacity management unit that stops load leveling operation of the high temperature operation type secondary battery when the compensation capacity is reached.

The high-temperature operation according to claim 7, wherein the remaining battery capacity is obtained from an electric capacity integrated value (Ah) based on a charge / discharge operation of the high-temperature operation type secondary battery or a remaining capacity converted value based on a depth estimated from a battery voltage. Type secondary battery system.

The high temperature operation type secondary battery system according to claim 1, wherein each component is multiple-parallelized.

The high temperature operation type secondary battery system according to any one of claims 1 to 9, wherein the high temperature operation type secondary battery is a sodium-sulfur battery.